ACTAR Vehicle Damage Analysis 2 — Questions and Answers
Question 1: In a collision, the term 'induced damage' refers to:
- Damage caused directly by the initial impact force
- Damage that occurs as a secondary result of primary damage or structural deformation (Correct answer)
- Damage inflicted intentionally before the accident
- Damage visible only under ultraviolet light inspection
Correct answer: Damage that occurs as a secondary result of primary damage or structural deformation
Induced damage is secondary damage that results from primary contact damage, such as a hood buckling because the front rail collapsed.
Question 2: The CRASH3 damage algorithm uses energy-stiffness coefficients (A and B) primarily to:
- Estimate the vehicle's pre-crash speed from skid marks
- Calculate crush energy absorbed by the vehicle structure (Correct answer)
- Determine the coefficient of friction on the roadway
- Establish the coefficient of restitution between two vehicles
Correct answer: Calculate crush energy absorbed by the vehicle structure
CRASH3 uses A (force-per-unit-width at zero crush) and B (stiffness) coefficients to compute the energy absorbed in vehicle crush deformation.
Question 3: Which measurement technique is used to quantify vehicle crush in the field for CRASH energy calculations?
- Measuring overall vehicle length before and after collision
- Taking six evenly-spaced crush depth measurements across the damage width (Correct answer)
- Photographing damage and estimating deformation by eye
- Measuring the height of the lowest damaged panel only
Correct answer: Taking six evenly-spaced crush depth measurements across the damage width
The standard method involves six uniformly-spaced perpendicular crush measurements (C1–C6) across the damaged zone width.
Question 4: A vehicle exhibits 'peripheral damage' in a collision analysis. This refers to:
- Structural damage to the vehicle's frame rails
- Damage to components at the edge of the contact area, such as mirrors or trim (Correct answer)
- Damage confined solely to the firewall
- Airbag deployment marks on the steering wheel
Correct answer: Damage to components at the edge of the contact area, such as mirrors or trim
Peripheral damage occurs at the margins of the contact zone and includes items like mirrors, lamps, and moldings that are struck tangentially.
Question 5: When analyzing a sideswipe collision, the direction of force (DOF) is typically:
- Perpendicular to the vehicle's longitudinal axis (Correct answer)
- Parallel to and toward the vehicle's longitudinal axis
- At approximately 45 degrees to the vehicle centerline
- Directly rearward along the vehicle centerline
Correct answer: Perpendicular to the vehicle's longitudinal axis
In a sideswipe, the primary force vector acts laterally — perpendicular to the vehicle's long axis — because contact occurs along the side.
Question 6: The stiffness coefficient 'A' in the CRASH3 model represents:
- The slope of the force-crush curve
- The residual force per unit width at zero crush depth (Correct answer)
- The total crush energy absorbed per unit area
- The vehicle's bumper height above ground
Correct answer: The residual force per unit width at zero crush depth
The A coefficient is the y-intercept of the force-crush relationship, representing the force per unit width required to initiate crush (at zero deformation).
Question 7: How does 'restitution' affect post-collision vehicle separation velocity in damage-based speed analysis?
- It has no effect; only crush depth matters
- A coefficient of restitution greater than zero means vehicles separate faster than a purely plastic collision would predict (Correct answer)
- Higher restitution always results in greater total crush energy
- Restitution only applies to pedestrian impacts, not vehicle-to-vehicle collisions
Correct answer: A coefficient of restitution greater than zero means vehicles separate faster than a purely plastic collision would predict
A non-zero coefficient of restitution means some elastic energy is returned, causing vehicles to rebound and separate at higher relative velocities than a perfectly plastic impact.
ACTAR Vehicle Damage Analysis 2
In a collision, the term 'induced damage' refers to: