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overview knowing automotive structures is a critical element for any inspector not just inspectors should know automotive structures as policies i.e naaa and general guidelines i.e i-car oem mitchell ase have been introduced to help guide sellers buyers and any facilitators of automobile sales on the appropriate disclosures related to structural damage like flood damage structural damage has a negative stigma and may affect the overall value of the vehicle however unlike flood damage not all structural damage is permanent structural damage is repairable to a certain point but if the repairs are not up to the manufacturer s standards the vehicle is unsafe how many of these vehicles have you inspected that had these repairs and missed how do you determine what is considered a structural component or not how do you detect prior repairs early detection will mitigate costly buying selling misrepresentation lost customer confidence time arbitration related issues and overall vehicle value loss almost a third of all arbitration complaints are frame related this guide will help you make better decisions related to automotive structures.[close]
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what to expect frame types the collision repair vs replace the inspection policies guidelines[close]
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12/4/2009 frame types overview proprietary variations exist but all fall under the 3 macro categories unibody frame unibody on a conventional frame conventional frame fuel efficiency and safety drive designs payload and durability capabilities also a factor the unibody structure as term suggests one complete shell comprised of a welded or chemically bonded assembly of relatively thin lightweight metals benchmarked from the `perimeter frame current trend most popular lightweight design aids fuel efficiency design manages collision forces aid in safety does not handle heavy payloads not as durable versus conventional frames source chief automotive 1[close]
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12/4/2009 unibody components per naaa c pillar not a structural component source naaa identifying a unibody structure aprons will be present strut towers will be present core support is typically welded to aprons rails and floor welded together no independent rail system source naaa 3[close]
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12/4/2009 conventional frames conventionally framed vehicles have a separate frame assembly to provide the main structural strength for the vehicle conventional frames are able to provide strength for large payloads and towing the frame is a separate component and it is not welded to any of the major units of the body shell the frame supports the suspension and drivetrain components as well as the body assembly the body suspension and drivetrain components are bolted to the frame separate body on frame designs were used in the first automobiles and continued to be the most common type of construction for several decades for that reason they are still called conventional frames although they are no longer the most common design for passenger cars conventional frames earliest frame type known why we call them conventional also known as full frame or body on frame differ from unitized designs by having a separate assembly can manage heavier payloads and is much more durable the body suspension and drivetrain components are bolted to the frame heavier so fuel efficiency is not as high conventional frames continued ladder style used primarily for trucks vans or suv 2 main rails that run the length of the vehicle 2 natural rises for vertical deflection series of crossmembers depending on specific make/model crossmembers can be bolted bonded or welded perimeter style benchmark for unibody flattened out for larger cars torque boxes serve as pillars side rails serve as rockers older technology source naaa 4[close]
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12/4/2009 identifying a conventional frame body is not welded to frame rails independent bolted to suspension and drivetrain no aprons no strut towers rails tend to be a thicker gauge metal iron core support is typically mounted by bolts only unibody on conventional frame also known as combination or combo frame unitized structure bolted to ladder style frame ability to support heavier payloads with added rigidity of upper structure not as popular anymore as most frames are being designed to be unibody or conventional source naaa identifying the unibody on frame unibody bolts to frame no strut towers core support is typically welded to aprons rails independent bolted to suspension and drivetrain has aprons rails tend to be a thicker gauge metal iron 5[close]
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12/4/2009 what happens during a typical collision there are no typical collisions its important to understand because easier for you to identify all damage paths your inspection will be faster your inspection will be more accurate collisions defined what is a collision in physics collision means the action of bodies striking or coming together touching collisions involve forces there is a change in velocity collisions can be elastic meaning they conserve energy and momentum inelastic meaning they conserve momentum but not energy or totally inelastic or plastic meaning they conserve momentum and the two objects stick together collisions may be a stationary object and moving object or two moving objects a collision will always be two or more objects resisting each other multiple collisions each time a vehicle rolls or hits another object additional forces are present vehicle collisions as a result of a collision each vehicle receives damage from two forces the external force exerted by the other vehicle or object and the internal force from within the vehicle itself source answers.com force what does force mean the capacity to do work or cause physical change energy strength or active power the force of an explosion power made operative against resistance exertion use force in driving a nail source answers.com 1[close]
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12/4/2009 inertia in physics the resistance of a body to any alteration in its state of motion i.e the resistance of a body at rest to being set in motion or of a body in motion to any change of speed or change in direction of motion inertia is a property common to all matter this property was first observed by galileo and restated by newton as his first law of motion sometimes called the law of inertia newton s second law of motion states that the external force required to affect the motion of a body is proportional to that acceleration the constant of proportionality is known as the mass which is the numerical value of the inertia the greater the inertia of a body the less is its acceleration for a given applied force source answers.com absorption deflection also known as crush collapse or crush zones sections of the structural members that are designed to collapse with predictable results upon impact simply as a result upon impact the automobile will consistently collapse according to a planned pattern as the crush zones collapse they absorb collision energy that could travel through the passenger compartment with greater force absorption deflection some components deflect energy rather than absorbing it a b c d pillars rocker panel itself serves as the subrail providing the majority of the needed rigidity for the center section rocker panels consist of a two part design 2[close]
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12/4/2009 basic frontal collision vehicle hits a rigid barrier the front section is the first to collide and takes on the majority of the `direct damage the front section will slow the force down and absorb deflect kinetic energy at this point the center and rear sections of the vehicle try to continue forward but are opposed by the front section based on the design of the vehicle the force is manipulated along a predetermined path collision hot-spots most complaints about damage are aprons front rails rear rails if you had only a minute to inspect for frame damage where would you look collision hot-spots continued if a bumper is still on look for misalignments if plastic is attached underneath look for turned bolts or other existing damage corrosion is a good indicator 3[close]
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12/4/2009 repair vs replace when is a replacement part needed what is a kink non-repairable what is a bend repairable could you should you repair vs replace continued i-car considers a part `bent when the change in shape of the part between the damaged and undamaged areas is smooth and continuous straightening by pulling restores its shape to preaccident condition without any areas of permanent deformation repair vs replace continued i-car considers a part `kinked when it has a sharp bend of small radius usually more than 90° over a short distance before or after straightening there are visible cracks or tears in the metal there is a permanent area of deformation which will not straighten to pre-accident condition or shape without the use of excessive heat shiny silver splinters appear in the stressed area hairline cracking appears on the surface 4[close]
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12/4/2009 repair vs replace continued radiator core support use the radiator support as an indicator for prior repairs or existing damage turned bolts inspect the baffles and aprons inspect the upper lower tie bars classifying the underbody planes vertical deflection sag mash/collapse lateral deflection sway hybrid deflection twist diamond 5[close]
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