Search Results

This research investigates the uncertainty in the calculation of the change in velocity, ΔV, and the crush energy, EC, due to variations in the computed values of crush stiffness coefficients, A and B (d₀ and d₁), and due to variations in the measurements of the residual crush, Ci, i = 1,...6, using the CRASH3 damage algorithm. An understanding of the nature of such uncertainties is of particular importance as both the ΔV and EC are frequently used as inputs to reconstruction methods and become variations in the reconstruction process. These variations lead to uncertainties in the results of the reconstruction which are generally the preimpact speed of one or both of the vehicles involved in the collision. This paper consists of three parts. The first investigates the uncertainty associated with the calculation of the stiffness coefficients A and B (d₀ and d₁).

More and more stores and catalog mail order houses have been offering the consumer a new type of towing device. Braided ropes and woven straps are being sold as replacements for towing chains and cables. Usually made from polypropelene or similar materials, they are strong, lightweight, inexpensive and easy to use. Unfortunately they are also easy to misuse; serious accidents have occurred. This paper presents a force, deflection and energy analysis of these straps in some idealized, but typical situations. It is shown that the relatively high strength but low flexibility can lead to point-of-attachment failures.