Car body consists of a base, roof and frame, including struts, spars, cross members, beams and reinforcements to which welded and hinged front parts are attached - plumage. Moreover, all welded body parts (mud flaps, arches, floors, panels, etc.) can be attributed directly to the supporting or reinforcing elements of the body frame.
As a result of an accident, the body may be damaged, traces may appear on its surface deformations, scratches, scuffs and other damage.
Deformation - changing the shape and size of the body(parts, structures) as a result of external influences without changing its mass. The simplest types are tension, compression, bending, torsion. Deformation is subdivided into superficial (smooth) and deep. As a result superficial deformations are formed dents, bulges. As a result deep deformations are formed folds,
extractions, fractures of the ribs, destruction of the integrity of the material or the connection with the formation of cracks, ruptures, separation of fragments,
The types of deformations and repairs of car bodies are defined in some detail in the VAZ regulations.
Scratch - it is a trace on the surface that does not disturb the shape of the surface.
Bully- damage leading to the violation of the surface material.
The bodies of modern passenger cars are a complex spatial system designed for high dynamic and static loads. As a load-bearing body, the body perceives loads through the elements of the load-bearing frame, as well as internal and external panels.
Under normal operating conditions, car bodies will reliably serve for 10-12 years or more.
It must be borne in mind that in the case of road accidents and when driving at high speeds on broken roads, permanent deformation occurs in the body.
The most damaging body damage occurs when frontal collisions, in case of collisions with the front part of the body at an angle of 40 - 45 ° or from the side. If such collisions occur between two vehicles moving towards them, then their speeds upon collision add up. In such collisions, to the greatest extent collapses front part car body. Acting at the same time high dynamic loads in longitudinal, transverse and vertical directions transferred to all adjacent frame parts body and especially its structural elements and can cause their deformation even from the opposite side.
Let's consider several examples of accidental body deformation.
The blow has been dealt in the front part of the body in the area of the left front fender, side member and left headlight(Fig. I). With this direction of impact, it is most likely that damage will affect following bodywork details:
radiator frame panels, bulkhead, fenders, hood, mudguards, front side members, windshield frame and roof. In the figures, this can be seen from the lines indicated by the dotted line.
The blow was inflicted on the car into the front part of the body at an angle about 40 - 45 ° (Fig. 2.). With this direction of impact, it is most likely that get damaged following bodywork details:
front fenders, hood, radiator frame panel, bulkhead, mudguard, front spars.
It is possible to restore the base points of the front part of the body using straightening methods. In this case, it is also necessary to restore the dimensions along the openings of the front doors and the coordinates of the front and central pillars, since the power loads were transmitted through the front doors to the front and central pillars of the body, and they acted with compressive forces on the threshold and the upper part of the sidewall of the body.
Fig. 2. Damage to the body when hitting the front at an angle of 40-45 °.
The impact was made from the side to the front part of the car body in the area of the interface between the front panel and the front part of the side member and the left wing (Fig. 3). With this direction of impact, it is most likely that damage will affect following bodywork details:
front fenders, radiator frame, bulkhead, mudguards, side members, hood. Tensile forces violated the opening of the left front door, compressive forces caused deformation in the opening of the right door and in the sidewall of the left front door. At the same time, the front and center struts also received significant power overloads and have deviations from their original location.
Fig. 3. Damage to the body in a side impact in the area of interface between the front panel and the side member.
Impact - from the side to the front pillar of the car body on the left side(Fig. 4). With this direction of impact, it is most likely that get damaged following bodywork details: .
left A-pillar, windshield frame, roof, floor and front side members, radiator frame, bulkhead, hood, fenders, mud flaps and front side members. In this case, the front of the car body "left" to the left; the sill and the upper part of the right sidewall took up tensile loads, central and rear pillars... - compressive loads; the right mudguard was "torn off" from the A-pillar. ...
Specifications 017207-255-00232934-2006 "Body LADA cars, technical requirements when accepting for repair, repair and release from repair by the enterprises of the service and sales network of JSC AvtoVAZ ", Togliatti 2006, provide the following types of repair damaged (deformed) bodies (TU clause 2.6.1.):
elimination of distortions body;
repair individual parts (straightening, welding);
replacement individual body parts or damaged parts;
coloration and anti-corrosion treatment ".
Body skew - this is violation beyond acceptable limits geometric parameters openings (windows, doors, hood, trunk lid), and the locations of the base attachment points
"Elimination of distortions body (TU clause 2.6.3) is the restoration of the geometric parameters of the openings of windows, doors, hood, trunk lid, side members, interior frame and base points on the base of the body for fastening power unit, transmissions and suspensions ".
The geometric parameters of the bodies are given in the TU (Appendix B). The presence of distortions is established by measuring the corresponding openings or the location of the base attachment points power unit, suspensions (bridges) and transmission units on the base of the monocoque body frame.
3.3. Elimination of distortions openings and bodywork must be before straightening and repair front panels.
3.4. Allowed produce elimination of distortions bodies both with front panels (fenders, sidewalls, front and rear panels, roofs), and with disconnected front panels.
3.6. Depending on the degree of deformation of the body, the following classification of distortions is established:
skewed opening;
uncomplicated body distortion;
body skew of medium complexity;
complex body distortion;
body distortion of particular complexity.
3.7. Depending on the degree of damage or corrosive destruction of the body part, the following are foreseen types of repair with removed units and parts that impede the carrying out of straightening, welding and painting works:
renovation.0- elimination of damage on the front surfaces of the body without damaging the paint;
repair 1- elimination of damage in readily available places (up to 20% of the surface of the part);
repair 2 - elimination of damage with welding or repair 1 on the surface of a part deformed up to 50%;
repair 3 - elimination of damage with opening and welding, partial restoration * details up to 30%;
repair 4 - elimination of damage with partial restoration * details on the surface over 30%;
Partial replacement - replacement of a damaged body part with a repair insert ** (from the range of spare parts or made from the latter); ...
Replacement- replacement of the damaged body part with a part from spare parts ***.
Large block repair- replacement of the damaged part of the body with blocks of parts from rejected bodies with marking, cutting, fitting, drawing, straightening, welding of the latter. "
* Partial restoration of a part- this is the elimination of damage by drawing or straightening, with shrinkage of the metal; cutting out areas that cannot be repaired; production of repair inserts from rejected body parts or sheet metal with giving it the shape of a restored part. "
** Partial replacement it is most often performed when narrow and long parts are damaged (cross members, spars, sidewalls), when it is economically more expedient to replace not the entire part, but only its damaged part.
*** Replacing a part the body is made in case of its unrepairability or economic inexpediency of its repair.
Body repair is often associated with the need to perform reinforcement works on disassembly, assembly, removal, installation nodes, details. The list of reinforcement works is given in the technology of maintenance and repair of the corresponding AMTS.
Reinforcement works most often include:
disassembly, assembly:
Front, rear and rear doors;
Removal and installation;
The hood and its mechanisms;
Battery;
Trunk lids and their mechanisms;
Windscreen, rear and side windows;
Rear lights;
Front and rear bumpers;
Antennas, speakers, radio, radio, turntable;
Heater;
Dashboards;
Roof upholstery;
Safety belts;
Sidenev;
Block headlights.
Labor intensity of work on repair (replacement) of body parts and elimination of body distortions, as a rule, do not take into account labor intensity of work on removal and installation of assemblies and parts that impede repair work.
In the laboriousness of replacing body parts taken into account the following works: detachment and removal of the old part, elimination of metal residues, loose and formation rust (corrosion), straightening of mating edges, fitting and welding new part, cleaning of welding spots and seams, leveling of surfaces with fillers and grinding of defective places. ("The complexity of work on maintenance and repair of VAZ cars " General Provisions item 9. Togliatti 2005)
Drawing up an inspection report
As a result of examination by a specialist identified and recorded in the relevant sections of the inspection report, all the information necessary for the assessment about the object of assessment, its damage, defects, repair technology, as well as his opinion on the cause of the detected damage.
1. IN IDENTIFICATION the section is entered:
REAL, and not indicated in the submitted documents, numbers a motor vehicle and its components (registration number, VIN identification number, body number, frame number, engine number, etc.);
odometer mileage;
For automatic telephone exchanges that are on warranty service, or which are repaired and serviced by authorized dealer or at a branded workshop, a special confirmation record must be made;
equipment a motor vehicle, the presence of additional, freelance, tuning equipment;
2. To section "INSTALLED DURING INSPECTION" the following information is entered, the correction of which is unacceptable:
was it produced replacement knots, assemblies and expensive components;
has been vehicle body repair earlier and what is its volume, nature and quality;
Availability on a motor vehicle, operational defects, first of all, the presence of metal corrosion (surface, deep or through).
Availability on a motor vehicle of emergency damage (deformations, scratches, scuffs, etc.), their type, nature, degree of complexity, size and location.
Damage can be classified according to the time of occurrence:
Related to this emergency;
Received from previous accidents.
The specialist conducting the inspection must draw probabilistic conclusions about the belonging of the detected damage to this incident and make an appropriate entry in the Inspection Report of the following nature:
“With a high degree of probability, it can be assumed that the damage to the car found during the inspection may be the result of an accident recorded in the attached Traffic Police Certificate. Damages, about which it can be assumed that they are NOT a consequence of this accident, are marked in the "CONCLUSIONS" section with two asterisks ** "
Defects can be classified as follows:
Obtained due to correct operation and storage of automatic telephone exchange;
Received as a result of incorrect operation and storage of automatic telephone exchange;
The result of poor-quality repair work.
Since the description of damages, defects does not always give a complete picture of them .. it is advisable to accompany information about damages, defects with appropriate photographs, video filming, sketches, sketches, diagrams, etc.
To this section UNWANTED include conclusions and proposals on the possibility, methods, ways of AMTS restoration (replacement or repair of parts, the amount of labor intensity of the repair, its technology, etc.).
Damage, with a high degree of probability, related to the "incident in question, it is desirable to include in the inspection report indicating their presence or absence in the traffic police certificate. It is also necessary to indicate damage, with a high degree of probability, not related to this incident.
The presence of severe metal corrosion, or other defects in the operation of the vehicle, affecting to a large extent the technology, the cost of repairs, should be noted in the inspection report.
After filling out the section in the "Inspection Certificate" "INSTALLED DURING INSPECTION" this section is signed by the specialist performing the inspection, and after familiarization, by the interested parties present at the inspection. All signatories should be able to state their dissenting opinion and remarks in the Inspection Certificate.
When drawing up the Inspection Certificate and other documents, you must use terminology, adopted in the normative, technical, technological documentation: in the manual for the repair technology, the manual for maintenance and repair, in the catalogs of spare parts and other technical literature.
Each damaged part should have a separate section line and, if possible, a photograph.
Inspection should be carried out systematically, consistently. One of the options for the inspection sequence can be a scheme based on the principle of transition from one inspected group of parts to another only after the description of all damaged parts included in the group of the same name is completed. The sequence of alternating groups is chosen by a specialist, and the order of subgroups is desirable in accordance with the increase in their ordinal number. The proposed inspection procedure avoids missing damaged parts during inspection and is very convenient when calculating a repair estimate, especially if it is performed using a computer.
For example, first we inspect the parts of the 28th group (frame, protective elements of the body), then 84 groups (plumage), etc.
3. For recommendations on the repair of a vehicle in the Inspection Report there is a section "CONCLUSIONS". This section is filled in by a specialist without discussion and agreement with other participants in the inspection, after analyzing the technical feasibility and economic feasibility of carrying out the proposed work.
During the initial examination of AMTS, it is not always possible to identify all damage and defects. In such cases, all assumptions for hidden damage, defects should be recorded in the Inspection Certificate and the document issued to the interested organization (person), but they should not be reflected in the cost of repairs until they are finally established during subsequent inspections
AMTS. The calculation of the cost of repairs may include the necessary control and diagnostic operations.
By agreement with the customer Inspection certificate may not be compiled. In this case, all the necessary data is entered into the report.
Table 4.3.1.
Similar information.
The car has a certain shape and size of parts. All these dimensions not only determine the design, location and fastening of the units, but also take into account the safety of the vehicle and its aerodynamic properties. The points on the body, on which these qualities of the car depend, are called basic. There are also control points on the body.
NOTE: Body geometry is a collection of all sizes and shapes of its parts. Violation of the body geometry is a change in the size and / or shape of parts (or one part) of the body, as a result of which the base and (or) control points on the body have been displaced.
The general picture of damage when violation of the geometry of the body make up deviations from the specified dimensions of the base and body frame. Even in the absence of visible deviations, the location of the base and control points on the body should be compared with the technical documentation for the car - after all, not everything is visible to the eye, sometimes you need to use measuring instruments, for example, a tape measure.
Damage to the car body varies by category of severity. The higher the category, the more difficult the damage and the more effort, time and money is required to eliminate it and give the body part its original shape.
The simplest damage is dents in the outer body parts. They refer to the first category of complexity.
If the damage did not affect driving performance car (it can be operated, only aesthetics in appearance is not enough) and the location of its main components, then they are damage second category of complexity. Such damage includes, for example, violation of the geometry of doorways, deformation of the middle pillars of the passenger compartment, etc.
If there has been a displacement of the main units of the car and (or) deformation of the supporting elements of the body, on which there are base points (spars, shock absorber cups, etc.), then such damage refers to the third category of complexity.
If the damage relates simultaneously to all three first categories, and the geometry of three or more window and door openings is violated, then this is damage fourth category of complexity. It is very difficult to restore a car that has suffered such damage.
Damaged car the fifth category of complexity, it is impossible to call it anything other than scrap metal. In other words, it cannot be restored. Almost all body dimensions and proportions are violated, almost all body parts need to be repaired, all base and control points are shifted, etc. With such damage, the foreman responds to the question "What can be done?" usually advises to remove the front and rear bumpers and insert between them new car... But the bumpers are likely to be broken. So in case of damage of the fifth category of complexity, the acquisition new car is cheaper than repairs (or at least a similar amount).
So, before you tackle body repair car, you need to objectively assess the complexity of the damage received and your ability to eliminate them. A novice craftsman can not cope with all injuries: for some, experience is simply needed, which is gained over time. If you do not have time to gain experience, confidence in your abilities - too, the car needs to be urgently restored, and the damage to the body is quite complex, then it is better to immediately contact a service station.
Body distortions and ways to eliminate them
Even a novice car owner knows that there are certain parameters of openings (windows, doors, hood, trunk lid) and the location of the base points of attachment of the power unit, suspensions, transmission units on the base of the body. The normal functioning of the car, all its assemblies and parts, controllability and stability can only be ensured by the correct location of the base points - in accordance with the requirements of the manufacturer. It is important to note that the manufacturer sets the requirements for the base points for a reason - this really ensures the safety and hassle-free operation of the car.
NOTE: Body misalignment is a violation of geometric parameters in excess of permissible limits.
A body is considered repaired when its original geometric parameters (body geometry) have been restored in accordance with the vehicle documentation.
When correcting the skew of the body, the following parameters are monitored:
¦ the size of the gaps between the body and attached parts;
¦ the size and shape of window openings (especially carefully you need to control the size and shape of the openings of the front and rear windows);
¦ relative position on the base of the body of base and control points.
Body skews are of five types.
1. Skewed opening. This is the skew of the side door, wind and rear windows, that is, such damage to the body, in which the parameters of one or more openings are violated beyond the permissible limits.
In fig. 1.5 you see the following misalignments of the opening:
Skew of the side door opening (a);
skew of the wind window opening (b);
skew of the rear window opening (c).
Rice. 1.5. Skewed opening
2. Uncomplicated body distortion. Such damage to the body is considered uncomplicated, in which the geometric parameters of the openings of the hood or trunk lid (hatchback rear door) change in excess of the permissible limits, but the geometry of the base and body frame, door and window openings is not disturbed (the gaps of doors with front or rear car wings).
In fig. 1.6 you see the following body distortions:
¦ skew of the hood opening (a);
¦ skew of the trunk lid opening (b);
¦ skewed hatchback rear door opening (v).
Rice. 1.6. Uncomplicated body distortion
3. Body skew of medium complexity. With such a misalignment, the geometric parameters of the hood opening and the trunk lid (rear hatchback door) are simultaneously violated or the body is damaged in violation of the geometric parameters of the front or rear side members beyond the permissible limits (but without violating the geometry of the body frame).
In fig. 1.7 you see the following body distortions of medium complexity: skewed hood opening and trunk lid (a); misalignment of the front and rear side members (b).
Rice. 1.7. Medium body skew
4. Complex skew of the body. With this misalignment, the geometric parameters of the front and rear side members (a) are simultaneously violated beyond the permissible limits; or the body is damaged in violation of the geometric parameters of the front or rear spars, and the body frame (b); or the geometric parameters of only the front side members are violated (if the car structurally does not have a front suspension cross member) (c) (Fig. 1.8).
Rice. 1.8. Complex body skew
5. Skew of the body of particular complexity. With this misalignment, damage to the body occurs in violation of the geometric parameters of the front and rear side members and the body frame in excess of the permissible limits; if the front suspension cross member is structurally absent, then the geometric parameters of only the front side members and the car body frame are violated (Fig. 1.9).
The presence of a skew of the body is determined by the change in the size of the gaps of the mating hinged and welded body panels. If the gaps differ from the standard, and the doors, hood and trunk lid are difficult to open or close, then the body frame is skewed in these places.
Rice. 1.9. Skewed body of particular complexity
To determine if there is a skew in the base of the body, it is often necessary to dismantle the upholstery, which covers the places of possible metal deformation in the area of the floor tunnel or wheel arches.
As a result of an accident, a variety of deformations can occur, which will significantly (and, of course, negatively) affect the further operation of the car. Deformations form folds in the floor and other elements of the base of the body or frame. As a rule, folds are formed in the impact zone, and in places remote from the impact zone - in long body parts (the longer the part, the more it is subject to deformation) and in the gaps between the welding points (if the gaps are large, the metal sheets can move relative to each other , resulting in folds).
To detect obvious deformations (for example, a crumpled hood or a crumpled trunk lid, damaged doors, an "accordion", which until recently was a wing of a car), it is enough to carefully examine the outside of the car. The matter may not end with such deformations, therefore, if during the repair process, somewhere in the middle of straightening work, you do not want to unexpectedly find a deformation that requires pulling the car body, it must be inspected on a lift. In this case, you will be able to assess the condition of the body base and frame. Inspection is carried out visually, and for a greater guarantee, in order to surely detect all the folds, it is also recommended to touch the parts of the machine with your hand. As you know, the palm and fingers are a rather sensitive control instrument, therefore, when feeling, you can find folds that are invisible to the eyes.
Deformations of the body can disrupt the correct position of the wheels (as a result, the car becomes unstable on the road, and the tires wear out quickly), as well as change the location of control points (that is, violate the diagonals). If body deformation is detected, it is necessary to check the camber, that is, to check the geometry of the axles. In this case, the position of the wheels on different sides of the vehicle is monitored and compared.
To check if the control and base points are not shifted, it is necessary to use the method of diagonal measurements or, using frame devices, check the location of the base points of the body base. Sometimes measurements have to be made on special stands (slipways), while it is necessary to completely disassemble the body.
The method of diagonal measurements is to control the distances between symmetrically located points of the base of the body in the diagonal and longitudinal directions. The lengths of the diagonals do not matter, only the symmetry of the control points is checked. If the diagonals turn out to be of different lengths (that is, asymmetric), then the skew of the body has definitely occurred. In fig. 1.10 shows a measurement diagram for determining the skew of the base of the body.
But even if measurements show that the points are symmetrical to each other, this does not mean that there is no skewing of the base of the body. The measurement results must be compared with the data in the vehicle documentation. If there are deviations from the established standard, then the level of these deviations indicates the degree of skewing of the base and body frame.
Elimination of body distortion. Before eliminating the distortions of the body, all components and parts of the car that can interfere with straightening, welding and painting must be removed. The machine must be installed on a slipway (Fig. 1.11).
Rice. 1.10. Measurement scheme for determining the skew of the base of the body (measurements are made in both the diagonal and longitudinal directions)
Rice. 1.11. Car on a slipway, ready to straighten body distortions
First of all, the geometry and shapes of the base and body frame are restored, and only then are the front panels straightening and straightening performed. Straightening and straightening work can be carried out both with removed and attached front panels.
If there are parts that, in principle, cannot be returned to their shape or installed in place properly, then they must be disconnected before starting work to eliminate the skew of the body.
The editing sequence is as follows: first, the tougher parts are straightened, and then the less rigid ones.
The central part of the body (interior) is restored first. The straightened sections are fixed with rigid braces (their position should be unchanged during the subsequent straightening of the body sections associated with them). After the central part has been restored, the straightening is performed luggage compartment and the engine compartment. And only then the threaded and fasteners of the body are restored (they can simply be replaced with new ones).
Measuring frame devices should be installed on the body being repaired. only to check its parameters. Any renovation work(straightening, drawing, straightening, etc.) with the installed measuring frame devices should not be performed. The geometry of the frame fixtures is checked on a serviceable body.
To check the openings of doors, bonnet, boot lid and windows, attachments and technological glasses can be used.
Skewing of the body opening is eliminated using mechanical or hydraulic braces. The kits of these guy wires include various stops, grips, extensions and brackets. These devices are designed to produce tensile and compressive forces in the body openings (up to 3-5 ton-forces) (Fig. 1.12).
The support parts of the guy ropes must be placed on rigid body elements. If this is not possible or if a different arrangement of the braces is required, wooden beams should be placed in order to evenly distribute the load on the body (otherwise the body may deform under the brace support).
Rice. 1.12. Installation of stops, clamps, brackets, extensions when straightening openings
The car is installed on an exhaust stand. In case of simple distortions of the body, simplified universal stands are usually used (Fig. 1.13) to extract damaged elements, while the body is rigidly fixed to the stand, and power devices are located outside the body (Fig. 1.14).
The drawing process is monitored using standard measuring instruments, frame fixtures or diagonal measurements. When working on such stands, the load can be applied at any angle to the longitudinal axis of the body, and the power devices allow you to change the direction of the force from horizontal to vertical.
If the skew of the body is complex, then a high-performance universal stand is needed, where the stretching force can reach 10 ton-forces or even more. Such stands are equipped with measuring systems, with the help of which the parameters of the straightened part of the body are controlled during the drawing process.
Rice. 1.13. Universal stand for straightening car bodies
To eliminate a simple skew, the car must be installed at a work station and the point to which efforts should be applied and the place of support of the power stretch on the body must be determined. Then you should select the equipment for the power devices (extension cords, stops, brackets and grips). Power brace with accessories is installed in the body opening in the direction of the required hood. In fig. 1.15 and 1.16 you see options for eliminating body distortions (arrows show the directions of application of forces).
To distribute the load where the power device is supported on the body, wooden beams (made of hardwood) can be used as a support. The force required to straighten the skew of the opening is created using a hydraulic or mechanical power stretch.
Rice. 1.14. Power device for simple body straightening
If damage to any part does not allow you to eliminate the skew of the opening, you also have to straighten out the deformation of the metal with a straightening tool. For example, if, in an accident, the car turned over and lay on the roof and, in addition to the skew of the opening, the struts are deformed, then they have to be straightened with a straightening tool in the process of straightening the skew of the opening. Otherwise, after the necessary stretching or compression of the opening, they can deform so that straightening will be either very difficult or even impossible.
Rice. 1.15. Installation of screw and hydraulic braces to eliminate distortions of door and window openings
Rice. 1.16. Installation of power devices to eliminate the skew of the hood or trunk lid (rear hatchback door)
After applying a tensile or compressive force, the geometry of the opening is checked. The editing is repeated until the opening geometry reaches the norm.
If necessary, during the straightening process, you can change the direction of the load application, adjusting the places where the power braces are installed and the force required for straightening when controlling the geometry of the opening. You can use multiple strength stretches at the same time.
Correction of complex distortions of body openings is carried out according to the same principle as editing of simple distortions.
To straighten complex distortions of openings, the vehicle is mounted on a universal straightening stand. In the direction of the straightening force of the body, it is installed and fixed power point, the necessary slings and grips are selected in order to secure them to the damaged part. Note that the effort must be applied precisely to the damaged part, and not next to it.
After the attachment points have been determined, the clamps are attached to the rigid elements of the damaged body part. The gripper is connected to the lever of the power device with chains.
NOTE: In this case, the hydraulic cylinder of the power device is at the beginning of the working stroke, the chain is pre-tensioned, and the angle of inclination of the chain is selected depending on the required direction of force application.
The pulling force is generated by a hydraulic cylinder. Thus, the extraction of the damaged part is carried out.
If necessary, when extracting a damaged part, as well as when straightening simple distortions, the deformations are straightened that prevent the elimination of the distortion (that is, straightening is performed simultaneously with the impact of power devices).
During the drawing process, it is necessary to control the geometry of the base points of the straightened part. For this, the extraction is carried out in stages, and measurements are taken after each stage, until a satisfactory result is achieved. The measurement results also indicate whether the drawing directions and the places where the force is applied should be changed.
If necessary, you can use two power devices and (or) additional power stretching (Fig. 1.17).
Rice. 1.17. Installation of power devices and stretch marks when correcting body distortion of medium complexity
If the skew of the body is of particular complexity and you have to use several power devices at the same time, then it is best to direct the power efforts in the directions opposite from the center of the body. Alternatively, the body can be secured to the bench using an additional load-bearing transverse beam.
If the power elements of the body base (side members and cross members) do not stretch or there is a possibility of their irreversible deformation as a result of the application of force forces, then during the straightening process it is necessary to disconnect the connecting elements (amplifiers and connectors) of the straightened power element (side member and cross members). The connecting elements are disconnected at the welding points and put in place at the end of the drawing.
After the extraction is complete, remove all auxiliary elements (power struts, braces, grips and chains). Then, the outer surfaces of the body parts are straightened and straightened. After straightening and straightening, the removed attachment body parts are installed in their places (the welded parts are fixed at the welding points).
If there are foci of corrosion on the surface of the body, then they must be eliminated when preparing the body for painting.
Source of information: Car painting and bodywork. Georgy Branikhin and Alexey Gromakovsky
Transport and trace examination of traces of damage studies the patterns of display in traces of information about the event of a traffic accident and its participants, methods of detecting traces Vehicle and traces on vehicles, as well as techniques for extracting, fixing and researching the information displayed in them.
At NEU "SudExpert" LLC, trace examination examinations are carried out in order to establish the circumstances that determine the process of interaction of vehicles upon contact. In this case, the following main tasks are solved:
- determination of the angle of relative position of vehicles at the moment of collision
- determining the point of initial contact on the vehicle
- establishing the direction of the collision line (direction of impact impulse or relative speed of approach)
- determination of the collision angle (the angle between the directions of the velocity vectors of cars before the collision)
- refutation or confirmation of contact-track interaction of vehicles
In the process of a trace interaction, both objects participating in it often undergo changes and become carriers of traces. Therefore, the objects of trace formation are subdivided into perceiving and generating in relation to each trace. The mechanical force that determines the mutual movement and interaction of objects participating in trace formation is called trace-forming (deforming).
The direct contact of the generating and perceiving objects in the process of their interaction, leading to the appearance of a trace, is called a trace contact. The contacting areas of the surfaces are called contacting. Distinguish between trace contact at one point and the contact of a set of points located along a line or along a plane.
What are the types of vehicle damage?
Visible trace
- a trace that can be directly perceived by sight. All superficial and depressed traces are visible;
Dent
- Damage of various shapes and sizes, characterized by indentation of the trace-receiving surface, which appears as a result of permanent deformation;
Deformation
- change in the shape or size of a physical body or its parts under the influence of external forces;
Bully
- traces of sliding with an elevation of pieces and part of the trace-receiving surface;
Layering —
the result of transferring the material of one object to the trace-perceiving surface of another;
Exfoliation —
separation of particles, pieces, layers of matter from the surface of the vehicle;
Breakdown —
through damage to the tire resulting from the introduction of a foreign object into it, with a size of more than 10 mm;
Puncture —
through damage to the tire resulting from the introduction of a foreign object into it, up to 10 mm in size;
The gap
- damage of irregular shape with uneven edges;
Scratch —
shallow superficial damage, the length of which is greater than its width.
Vehicles leave footprints by applying pressure or friction to the sensing object. When the trace-forming force is directed normal to the trace-receiving surface, pressure is noticeably prevailing. When the track-forming force has a tangential direction, friction dominates. When vehicles and other objects come into contact in the process of a road traffic accident due to impacts of different strength and direction, traces (tracks) appear, which are divided into: primary and secondary, volumetric and superficial, static (dents, holes) and dynamic (scratches, cuts ). Combined marks are dents that turn into slip marks (they are more common), or vice versa, slip marks ending in a dent. In the process of trace formation, so-called "paired traces" arise, for example, a layering trace on one of the vehicles corresponds to a paired delamination trace on the other.
Primary traces- traces that have arisen in the process of primary, initial contact of vehicles with each other or vehicles with various obstacles. Secondary traces are traces that appeared in the process of further displacement and deformation of objects that entered into a trace interaction.
Volumetric and superficial traces are formed due to the physical effect of the forming object on the perceiving one. In the volumetric trace, the features of the generating object, in particular, protruding and recessed relief details, receive a three-dimensional display. In the surface trace there is only a planar, two-dimensional display of one of the surfaces of the vehicle or its protruding parts.
Static traces are formed in the process of trace contact, when the same points of the forming object affect the same points of the perceiver. Point mapping is observed provided that at the moment of trace formation, the forming object moved mainly along the normal relative to the plane of the trace.
Dynamic traces are formed when each of the points on the surface of the vehicle sequentially acts on a series of points on the receiving object. The points of the generating object receive the so-called transformed linear mapping. In this case, each point of the generating object corresponds to a line in the trace. This occurs when the generating object is tangentially displaced relative to the perceiving one.
What damage can be a source of information about an accident?
Damage as a source of information about a road traffic accident can be divided into three groups:
First group - damage resulting from the mutual introduction of two or more vehicles at the initial moment of interaction. These are contact deformations, a change in the original shape of individual vehicle parts. Deformations usually occupy a significant area and are noticeable during external examination without the use of technical means. The most common deformity is a dent. Dents are formed in the places of application of forces and, as a rule, are directed towards the inside of the part (element).
Second group - these are gaps, cuts, breakdowns, scratches. They are characterized by through destruction of the surface and the concentration of wake-forming forces over an insignificant area.
Third group damage - imprints, i.e. surface displays on the trace-perceiving area of the surface of one vehicle of protruding parts of another vehicle. Imprints are exfoliation or layering of a substance that can be reciprocal: the flaking of paint or another substance from one object leads to a stratification of the same substance on another.
Damages of the first and second groups are always volumetric, injuries of the third group are superficial.
It is customary to distinguish also secondary deformations, which are characterized by the absence of signs of direct contact of parts and parts of vehicles and are a consequence of contact deformations. Parts change their shape under the influence of the moment of forces arising in the case of contact deformations according to the laws of mechanics and resistance of materials.
Such deformations are located at a distance from the place of direct contact. Damage to the side member (side members) of a passenger car can lead to skewing of the entire body, i.e. the formation of secondary deformations, the appearance of which depends on the intensity, direction, place of application and magnitude of force in the course of a road traffic accident. Secondary deformities are often mistaken for contact deformities. To avoid this, when inspecting vehicles, first of all, traces of contact deformations should be identified, and only then can secondary deformations be correctly recognized and highlighted.
The most complex damage to a vehicle are distortions, characterized by a significant change in the geometric parameters of the body frame, cab, platform and stroller, door openings, hood, trunk lid, windshield and rear window, side members, etc.
The position of vehicles at the moment of impact during the transport-traceological examination, as a rule, is determined in the course of an investigative experiment on the deformations that have arisen as a result of the collision. To do this, the damaged vehicles are placed as close to each other as possible, while trying to combine the areas that were in contact upon impact. If this cannot be done, then the vehicles are positioned in such a way that the boundaries of the deformed sections are located at equal distances from each other. Since it is rather difficult to carry out such an experiment, the position of vehicles at the moment of impact is most often determined graphically, by drawing the vehicles to a scale, and by drawing damaged zones on them, the angle of collision between the conventional longitudinal axes of the vehicles is determined. Especially good result gives this method in the examination of oncoming collisions, when the contacting areas of vehicles in the process of impact do not have a relative displacement.
The deformed parts of the vehicles with which they came into contact make it possible to roughly judge the relative position and mechanism of interaction of vehicles.
When hitting a pedestrian characteristic damage of the vehicle are deformed parts with which the blow was inflicted - dents on the hood, fenders, damage to the front pillars and windshield with layers of blood, hair, fragments of the victim's clothing. Traces of layering of clothing fibers on the side parts of vehicles will make it possible to establish the fact of contact interaction of vehicles with a pedestrian during a tangential impact.
When overturning vehicles, typical damages are deformations of the roof, body pillars, cab, hood, fenders, doors. Traces of friction on the road surface (cuts, tracks, paint peeling) also testify to the fact of overturning.
How is traceological examination carried out?
- external inspection of the vehicle involved in the accident
- photographing general view vehicle and its damage
- fixing malfunctions resulting from a road traffic accident (cracks, breaks, breaks, deformations, etc.)
- disassembly of units and assemblies, their troubleshooting to identify hidden damages (if possible, these works)
- determination of the causes of the detected damage in terms of their compliance with the given road traffic accident
What to look for when inspecting a vehicle?
When inspecting a vehicle that participated in an accident, the main characteristics of damage to body elements and tail of the vehicle are recorded:
- location, area, linear dimensions, volume and shape (allow you to highlight the zones of localization of deformations)
- the type of damage formation and the direction of application (allow you to highlight the surfaces of trace perception and trace formation, to determine the nature and direction of movement of the vehicle, to establish the relative position of vehicles)
- the primary or secondary nature of the formation (allow to separate the traces of repair effects from the newly formed traces, to establish the stages of contact, in general to make a technical reconstruction of the process of introducing vehicles and the formation of damage)
The collision mechanism of vehicles is characterized by classification features, which are divided by traceology into groups according to the following indicators:
- direction of movement: longitudinal and cross; the nature of mutual rapprochement: oncoming, passing and transverse
- the relative position of the longitudinal axes: parallel, perpendicular and oblique
- the nature of the interaction upon impact: blocking, sliding and tangential
- direction of impact in relation to the center of gravity: central and eccentric
More detailed free consultation on transport and traceological expertise can be obtained by calling NEU "SudExpert" LLC
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4. Methodological provisions for establishing the presence
and the nature of technical damage to vehicles
4.1. The presence and nature of technical damage to vehicles is determined by the type of impacts that caused them, which are divided into mechanical, thermal and chemical.
4.1.1. Mechanical effects are caused by the mechanical interaction of the examination object with other vehicles or objects, as well as explosions. The main types of damage caused by mechanical stress include scratches, chipping, denting, scuffing, extrusion, chipping, separation, breakage, shearing, knocking out, falling out, peeling, rupture, puncture, breakdown, fold, crack, change in the arrangement of structural elements relative to each other. friend (skew, displacement, jamming, jamming, sinking, beating, stretching, twisting, bending), complete destruction.
4.1.2. Thermal influences are caused by the action of high temperatures on the object of examination as a result of a fire or explosion. The main types of damage caused by thermal effects include swelling, burning, melting, carbon deposits, warpage.
4.1.3. Chemical influences are caused by reactions occurring under the influence of chemically hazardous substances (cargo) on the object of examination or during explosions. The main types of damage caused by chemical attack include corrosion, swelling, melting, flaking, carbon deposits, warpage.
4.2. According to the impact on the performance of the vehicle, technical damage is divided into failures and malfunctions. Failure is the loss of the vehicle's performance due to an unacceptable change in its parameters or properties. A malfunction characterizes the state of the vehicle, in which at least one of its main or additional parameters does not meet the requirements of technical documentation, as a rule, without losing the vehicle's performance.
4.3. According to the degree of manifestation and the possibility of detection, technical damage is divided into detectable by organoleptic methods and hidden. Research methods are used to identify hidden damage technical condition vehicle with the use of technical diagnostics.
4.4. Damage as a source of information about a road traffic accident can be divided into 3 groups.
The first group is damage resulting from the mutual introduction of two or more vehicles at the initial moment of interaction. These are contact deformations, a change in the original shape of individual vehicle parts. Deformations usually occupy a significant area and are noticeable during external examination without the use of technical means. The most common deformity is a dent. Dents are formed in the places of application of forces and, as a rule, are directed towards the inside of the part (element).
The second group includes tears, cuts, breakdowns, scratches. They are characterized by through destruction of the surface and the concentration of wake-forming forces over an insignificant area.
The third group of damages is prints, i.e. surface displays on the trace-perceiving area of the surface of one vehicle of protruding parts of another vehicle. Imprints are exfoliation or layering of a substance that can be reciprocal: the flaking of paint or another substance from one object leads to a stratification of the same substance on another.
Damages of the first and second groups are always volumetric, injuries of the third group are superficial.
4.5. It is customary to distinguish also secondary deformations, which are characterized by the absence of signs of direct contact of parts and parts of vehicles and are a consequence of contact deformations. Parts change their shape under the influence of the moment of forces arising in the case of contact deformations according to the laws of mechanics and resistance of materials. Such deformations are located at a distance from the place of direct contact. Damage to the side member (side members) passenger car can lead to skewing of the entire body, i.e. the formation of secondary deformations, the appearance of which depends on the intensity, direction, place of application and the magnitude of the force in the process of a road traffic accident. Secondary deformities are often mistaken for contact deformities. To avoid this, when inspecting vehicles, first of all, traces of contact deformations should be identified, and only then can secondary deformations be correctly recognized and highlighted.
4.6. The most complex damage to a vehicle is distortion, characterized by a significant change in the geometric parameters of the body frame, cab, platform and stroller, door openings, hood, trunk lid, windscreen and rear glass, side members, etc.
4.7. The main share of technical damage to a vehicle is damage to body elements and empennage. The body and empennage of a passenger car include the following main elements: body frame, hood, trunk lid (tailgate), side doors, fenders, decorative details (radiator trim panel, front and rear bumpers, decorative trims, etc.). The main elements of the body and empennage truck are: frame, cab, cab doors, radiator trim panel, hood, fenders, footrests, side platform (base, sides, tarpaulin frame) or bucket-type platform and subframe for a dump truck. The main elements of the body and tail of the bus are: body (base - frame, floor panels, floor covers, front - frame and panels, sidewall - frame and panels; rear - frame and panels, roof - frame and panels), front door, backdoor, driver's cab door, hood, front fenders, rear fenders, footrests.
Damage to body and empennage elements is characterized by the area of damage, the location of the damage, their linear and volumetric dimensions (length, width, depth), shape, as well as their coordinates relative to the undamaged part of the vehicle.
According to the degree of deformation, damage to body and tail elements made of sheet material is divided into three groups. The first group includes damage to the surface of an element that did not cause a change in the shape of this element (scratches, small dents), the second - damage that caused smooth deformation (without folds and creases) of the element, the third group - damage that caused complex deformation (folds, creases ) element.
4.8. Damage to the tires of a vehicle is subdivided into punctures, punctures, cuts, ruptures, "pneumatic explosions", tire bead, tire tread peeling.
4.9. When describing technical damage, it is advisable to use classifiers of damage to vehicles, in particular, the Unified classifier of malfunctions of automotive products.
Traffic rules, approved by the resolution of the Council of Ministers of the Russian Federation "On Traffic Rules" dated 23.10.1993, No. 1090 (with amendments that came into force on 01.04.2001), state that in the event of an accident, the driver involved in it is obliged “Take possible measures to provide first aid to the injured, call the ambulance teams and the disaster medicine center, the rescue service. V emergency cases send the injured person on the way, and if this is not possible, take him to the nearest medical institution by his own vehicle ”.
Today, road traffic injuries around the world have become an epidemic. At the same time, a clear pattern can be traced between the number of deaths in road traffic accidents (RTA) and the level of economic development of the country. The death toll in Russia (per 1 million vehicles) is 3 - 5 times higher than in countries with developed road infrastructure. In our country, in recent years, there has been an alarming trend of growth not only in the number, but also in the severity of injuries sustained as a result of road accidents.
Road traffic accidents are divided into the following types:
1. Collision;
2. Rollover;
3. Collision with a stationary vehicle;
4. Hitting a pedestrian;
5. Hitting an obstacle;
6. Hitting a cyclist;
7. Hitting a horse-drawn vehicle;
8. Hitting animals;
9. Fall;
10. Other incidents;
Crossing, crushing and collision impact are the main traumatic factors leading to injury and injury in road accidents. Trauma is caused not only by cars, but also by road elements. The wounds in such cases are varied and complex. Naturally, the severity of the injury is primarily determined by the speed of the vehicle. The most serious injuries to a person in a car are received when they hit the door, steering column, windshield. Analysis of fatal injuries showed that 52% of them were caused by deformation of the body, and 48% were due to a passenger hitting the inside of the car.
In addition to speed, the severity of damage received as a result of an accident can be influenced by the make of the car, its weight, the nature of the impact (head-on or tangential collision), the presence of an airbag and seat belts, and a safe steering column. Using seat belts more than 3 times reduces the number of fatalities in a frontal collision *.
* Among drivers and passengers who do not wear seat belts, 46.3% are injured, 3% of road traffic accidents are killed. For people wearing seat belts, these values are 19.2% and 0.8%.
The most frequent (more than 70%) and most dangerous injuries in road traffic accidents are head injuries (bruises, compression of the brain, intracranial hematomas), injuries of the chest - chest and chest organs - lungs, heart and spinal injuries (especially the cervical spine).
The main reasons for the death of the victims are:
a combination of shock and blood loss - 40-50%;
severe traumatic brain injury - 30%;
injury incompatible with life - 20%.
In addition, the causes of high mortality are the time factor (late started health care) - the rule of the "golden hour" and the low level of training of drivers and traffic police officers of the Ministry of Internal Affairs of Russia in the techniques and skills of providing first aid to victims.
A car injury is damage caused to the exterior and interior of a moving vehicle, or from falling out of the vehicle. There are the following types of car injuries:
1. Impact by parts of the car in a collision with a person;
2. Moving by wheel or wheels;
3. Falling out of the car;
4. Impact on a part or compression of the body by parts of the car in the cockpit;
5. Compression of the body between parts of the car and other objects;
6. Combined type of injury.
Damage resulting from a collision with a moving vehicle (collision) is the most common. This type of car injury includes several successive stages.
1. Impact of parts of the car with a person. The mechanism of damage is shock and general concussion of the body. Damage occurs on clothing and body, reflecting the contours of a part or the edges of the bumper, headlight, radiator grille, etc.
Localization of injuries - the lower limbs, the pelvic region, less often - the trunk, at the level of those parts of the car with which they were inflicted (contact damage, stamp damage).
2. The body fell onto the vehicle. Mechanism - impact on a part of the car (hood, fender, wiper fitting, etc.).
Localization - areas of the head, trunk, upper limbs. It should be borne in mind that the body is thrown onto a car during the initial impact below the center of gravity of a person (when hit by a car). If the primary blow is struck near the center of gravity (by a truck, bus, etc.), the body is thrown forward.
3. Throwing and falling of the body on the ground. The mechanism is an impact on the ground. Localization - the region of the head, trunk, upper limbs.
As a result of the collision, the human body acquires a speed close to the speed of the machine, as well as a rotational motion around the longitudinal axis.
Sliding the body on the ground. The mechanism is friction against the ground.
In a collision with a moving vehicle, the so-called bumper damage arising from a bumper hitting the thigh or lower leg, depending on the height of its location, is of particular importance. On the skin at the points of contact, a transverse banded bruise, abrasion or wound often occurs. Of particular importance is a transverse comminuted fracture of the leg and femur bones. In the area of the fracture, in typical cases, a large wedge-shaped fragment is revealed, the base of which shows the location, and the sharp end shows the direction of the impact.
As a result of being hit by parts of the car, falling of the body on the car, throwing it on the ground, damage to the soft tissues of the head occurs, as well as fractures of the skull bones. Most often these are direct, closed, linear and comminuted fractures. Combined fractures of the bones of the vault and base of the skull are often observed. Linear and comminuted fractures originate at the site of impact and spread radially in different directions in the plane of injury, as if graphically marking the direction of impact on the skull. Damage to the brain, its membranes, blood vessels occurs at the site of application of force and in areas remote from the site of impact (in the area of the counter-impact).
A severe blow to the upper thighs and pelvis often results in straight, linear or comminuted fractures of the pelvic bones. Such fractures are often accompanied by damage to the pelvic organs. When struck from behind, the cervical and upper thoracic spine is often damaged as a result of a sharp excessive extension of the body.
Lorry, bus or trolleybus impact injuries are often localized to the chest area. In this case, damage can occur from objects with an extensive or limited (in case of impact by protruding parts) traumatic surface. A blow to the chest leads to unilateral (usually straight) multiple fractures of the ribs, arising at the site of direct application of force.
A blow from a car with the subsequent throwing away of the victim is often accompanied by a complex of indirect injuries to internal organs due to a concussion of the body. The most commonly damaged liver, lungs, kidneys and spleen. The abdominal organs are damaged more often than the chest.
With the so-called moving of vehicles through the victim's body, a complex of injuries occurs, which is characteristic of this mechanism of injury. Firstly, hemorrhages are formed, reflecting the tread pattern of the wheels, secondly, exfoliation of skin and other tissues in the form of pockets filled with blood are formed, and thirdly, traces of body dragging appear in the form of extensive abrasions. When the wheel travels over the chest or abdomen, tears and crushing of internal organs are often observed. With the same effect on the head, there remain: its significant deformation, comminuted fractures of the skull bones and crushing of the brain.
A driver's injury inside the passenger compartment in a frontal collision is characterized by a complex of damage arising from the action of the steering wheel, instrument panel and windshield in the form of bruises and compression of the chest and abdomen, accompanied by fractures of the ribs, ruptures of internal organs. From the windshield, damage in the form of bruises, wounds and abrasions is localized on the face and head.
