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A crash pulse representative of the accident event is often requested in addition to the reconstructed speed, deltaV, and PDOF. One approach to crash pulse generation is to scale available test data to the accident condition. Scaling formulas for time and acceleration are derived based upon commonly available accident reconstruction information from the crush profiles, closing speed, and vehicle deltaV. Scaling is based upon the compression phase of the crash pulse. A crash test similar to the accident may not be readily available unless a crash test is performed that is designed to represent a specific accident. Available test results may not reproduce the accident but may approximate it in several important aspects. In such situations it is necessary to scale a reconstructed crash pulse from the most representative test available based upon the test parameters and the reconstruction estimates.

Frontal, side, rear, pole and offset car to car data sets are examined using familiar damage analysis models: constant stiffness, bilinear stiffness, and force saturation. In addition to these, a non-linear power-law formulation is introduced and compared to the others. The power-law provides a nonlinear stiffness coefficient that transitions between a constant force model and constant stiffness model as the power goes from 0 to 1. It also provides a continuous, single valued function that is easily integrated and used in the analysis. Power-law nonlinearity can be used to smoothly fit low through high crush data. Geometric integral parameters are developed which represent irregular crush profiles. These permit graphical comparison of tests with non-uniform crush data (such as offset, side, and narrow object) with uniform crush test data. They also provide a means for comparison of accident damage with the test data set.

Damage analysis methods in accident reconstruction use an estimate of vehicle stiffness together with measured crush to calculate crush energy, closing speed, and vehicle delta-V. Stiffness is generally derived from barrier crash test data. The accident being reconstructed often involves one or more conditions for which vehicle stiffness is not well defined by existing crash tests. Massive moving barrier (MMB) testing is introduced as a tool to obtain additional and accident specific stiffness coefficients applicable for reconstruction. The MMB impacts a stationary vehicle of similar structure as the accident vehicle under accident-specific conditions like impact location, angle, over-ride / under-ride, offset and damage energy. A rigid or deformable structure is mounted to the front of the MMB, representative of the impacting structure in the accident. Four illustrative tests are presented.