Unitized Structural Body Repair Exam (Questions and Answers)Latest
Updated 2025 (A+ Graded Verified)
Unibody - ANSWER Lightweight stamped sheet metal components that are welded to each
other to create a single unit.
Space Frame - ANSWER Body panels can be made from plastic are steel. Steel may be Mild,
Intermediate, or HSS. Panels may hide damage to frame or structure.
Crush Zones - ANSWER Structural components such as rails are designed to collapse and
bend at specific points.
Collision Energy Management - ANSWER Goal is passenger protection. Front and rear
structures act as crush-able energy absorbers.
Direct Damage - ANSWER POI. Easily located and diagnosed.
Indirect Damage - ANSWER transmission of collision energy beyond the area of immediate
impact. Examples; Split seam sealers, pulled spot welds, misaligned panels, buckles in steel,
cracked glass, and cracked or chipped paint.
Passive Restraint Systems - ANSWER Must have service manual. No two are alike.
Datum - ANSWER Imaginary plane or line beneath the vehicle. Measures height.
Centerline - ANSWER Vertical plane that passes from the front of the vehicle to the rear.
Measures Width. May have stamped marks on vehicle body structure. Is confirmed by
referencing at last 3 width measurements in the undamaged portion of the vehicle.
Zero Planes - ANSWER Vertical plane that passes from side to side. Confirmed by measuring 3
length measurements from the undamaged portion of the vehicle.
Symmetry - ANSWER Equal on each side of the vehicle.
Asymmetrical - ANSWER Unequal on each side of the vehicle. (spare tire well)
Reference Points - ANSWER Bolts or nuts, Holes, Mechanical attachment points, Edges of
panels, Door strikers, Corner of openings. Common tolerance is =/.3mm (1/8) or all the way to
1mm (1.32).
Loaded Measurements - ANSWER Drivetrain In
Unloaded Measurements - ANSWER Drivetrain out
, Point to Point Measurements - ANSWER shortest distance between 2 reference points. AKA "as
the crow flies". Uses tram or steel tape measure.
Datum Measurements - ANSWER Taken at Datum plane, height differences between reference
points. Laser measuring system
Computerized Measuring System - ANSWER compare data stored in a software program or a
central database. Get hard copy of measurements. Can watch while pulling.
Steel - ANSWER Cannot know what kind by visible. Must check service manual.
Tensile Strength - ANSWER Amount of pressure/force necessary to fracture or tear steel.
Yield Strength - ANSWER Amount of force/pressure necessary to deform steel permanently.
PSI - ANSWER Pounds per inch /// tensile and yield strengths are expressed. Higher the
number the stronger the steel.
Mild Steel - ANSWER Cosmetic, used on Space frames, May be stressed relieved with heat,
tears can be welded without a loss of strength. Yield strength 30,000 PSI
Intermediate Steel - ANSWER Yield strength 30,000-70,000 PSI, structural and cosmetic, may
be affected by excessive heat, small tears can be welded w/o loss of strength.
High Strength Steel (HSS) - ANSWER Yield strength between 30,000-100,000 PSI, used in
cosmetic and structural, is destroyed by exceeding temperature or time limits, should be
replaced if kinked or torn excess of 1/4 inch, should be straightened cold whenever possible.
Ultra High Strength Steel (UHSS) - ANSWER Very high yield strength exceeding 100,000 PSI,
must never be repaired, door intrusion beams and re-bars.
MIG/GMAW Welding - ANSWER
Stick-Arc, and Oxy-Acetylene - ANSWER Are not recommended for unibody repair. They heat
up to large of an area that is not needed. you want to weld the smallest area possible.
Compression Spot Welding - ANSWER Used by manufactures, but is not recommended for
collision repair. Our equipment makes welds 70-80%of the strength of manufactures.
Manufactures may have technicians use but must follow service manual and special
procedures.
MIG Welding Wire (Electrode) - ANSWER AWS ER70S-6 AWS ER70S-7
AWS - ANSWER American Welding Society Standard
Updated 2025 (A+ Graded Verified)
Unibody - ANSWER Lightweight stamped sheet metal components that are welded to each
other to create a single unit.
Space Frame - ANSWER Body panels can be made from plastic are steel. Steel may be Mild,
Intermediate, or HSS. Panels may hide damage to frame or structure.
Crush Zones - ANSWER Structural components such as rails are designed to collapse and
bend at specific points.
Collision Energy Management - ANSWER Goal is passenger protection. Front and rear
structures act as crush-able energy absorbers.
Direct Damage - ANSWER POI. Easily located and diagnosed.
Indirect Damage - ANSWER transmission of collision energy beyond the area of immediate
impact. Examples; Split seam sealers, pulled spot welds, misaligned panels, buckles in steel,
cracked glass, and cracked or chipped paint.
Passive Restraint Systems - ANSWER Must have service manual. No two are alike.
Datum - ANSWER Imaginary plane or line beneath the vehicle. Measures height.
Centerline - ANSWER Vertical plane that passes from the front of the vehicle to the rear.
Measures Width. May have stamped marks on vehicle body structure. Is confirmed by
referencing at last 3 width measurements in the undamaged portion of the vehicle.
Zero Planes - ANSWER Vertical plane that passes from side to side. Confirmed by measuring 3
length measurements from the undamaged portion of the vehicle.
Symmetry - ANSWER Equal on each side of the vehicle.
Asymmetrical - ANSWER Unequal on each side of the vehicle. (spare tire well)
Reference Points - ANSWER Bolts or nuts, Holes, Mechanical attachment points, Edges of
panels, Door strikers, Corner of openings. Common tolerance is =/.3mm (1/8) or all the way to
1mm (1.32).
Loaded Measurements - ANSWER Drivetrain In
Unloaded Measurements - ANSWER Drivetrain out
, Point to Point Measurements - ANSWER shortest distance between 2 reference points. AKA "as
the crow flies". Uses tram or steel tape measure.
Datum Measurements - ANSWER Taken at Datum plane, height differences between reference
points. Laser measuring system
Computerized Measuring System - ANSWER compare data stored in a software program or a
central database. Get hard copy of measurements. Can watch while pulling.
Steel - ANSWER Cannot know what kind by visible. Must check service manual.
Tensile Strength - ANSWER Amount of pressure/force necessary to fracture or tear steel.
Yield Strength - ANSWER Amount of force/pressure necessary to deform steel permanently.
PSI - ANSWER Pounds per inch /// tensile and yield strengths are expressed. Higher the
number the stronger the steel.
Mild Steel - ANSWER Cosmetic, used on Space frames, May be stressed relieved with heat,
tears can be welded without a loss of strength. Yield strength 30,000 PSI
Intermediate Steel - ANSWER Yield strength 30,000-70,000 PSI, structural and cosmetic, may
be affected by excessive heat, small tears can be welded w/o loss of strength.
High Strength Steel (HSS) - ANSWER Yield strength between 30,000-100,000 PSI, used in
cosmetic and structural, is destroyed by exceeding temperature or time limits, should be
replaced if kinked or torn excess of 1/4 inch, should be straightened cold whenever possible.
Ultra High Strength Steel (UHSS) - ANSWER Very high yield strength exceeding 100,000 PSI,
must never be repaired, door intrusion beams and re-bars.
MIG/GMAW Welding - ANSWER
Stick-Arc, and Oxy-Acetylene - ANSWER Are not recommended for unibody repair. They heat
up to large of an area that is not needed. you want to weld the smallest area possible.
Compression Spot Welding - ANSWER Used by manufactures, but is not recommended for
collision repair. Our equipment makes welds 70-80%of the strength of manufactures.
Manufactures may have technicians use but must follow service manual and special
procedures.
MIG Welding Wire (Electrode) - ANSWER AWS ER70S-6 AWS ER70S-7
AWS - ANSWER American Welding Society Standard
