Damage Analysis in Multiple Impact Rear-End Collisions

Questions/Topics Related to the CRASH computer program
#CRASH #EDCRASH #PC-CRASH
MSI
Site Admin
Posts: 2302
Joined: Thu Jun 18, 2009 12:37 pm

Damage Analysis in Multiple Impact Rear-End Collisions

Post by MSI »

Q: Does anyone know of publication which address the reduction in delta v in a multiple vehicle rear-end collision scenario. I have reviewed SAE 2010-01-0055 but was hoping that there might be others out there as well.

A: You ask about “reduction in delta v in a multiple vehicle rear-end collision scenario” and “whether or not there would be enough energy coming into the system after all the movement and damage to even get to the fourth vehicle's crush damage”

Multiple vehicle impacts on the structure of a vehicle presents many complexities.
  • First because data/research related to damage analysis on the reloading of vehicle structures is limited…
    However…
    if you look up Prasad and the NHTSA "reformulation" you will see a lot of multiple barrier impact tests on vehicle structures and they did many on rear impacts. You might find some good data points for rear impacts with multiple impacts.
I have not read SAE 2010-01-0055 (I will add to my list). I hope/expect they referenced Prasad’s NHTSA tests as a baseline? In the reports related to the crash tests the damage and accelerations were measured for each vehicle being crashed multiple times and that might provide some indication of the ‘residual crush stiffness’ of a damaged vehicle. Obviously these were not multiple low speed impacts however provide some indication of what type of loading in multiple impacts (each test report should include the acceleration time histories)

I’m not sure I understand what another response to this meant by “Crush energy is mostly related to the restitution between the vehicles”
  • the main amount of crush energy is due to the structural loading. I expect he meant in low speed impacts once you damage the vehicle the restitution on subsequent impacts will be lower since the bumper/structure is damaged.
In CRASH type damage analysis the energy and increase in deltaV due to restitution is ignored.
  • Damage analysis equates the barrier impact speed to the residual crush which is a ‘virtual crush stiffness’ relationship. Restitution is the energy feedback which is a source of problem with simple damage analysis since as we have said many times
    Restitution acts to reduce the residual damage while increasing the impact speed change

Here’s information on restitution What is Restitution?

I expect no information on relative impact and rest positions? From that you might be able to run some form of simulation to do a trajectory analysis?

This topic has 2 more posts with additional information

To Read more, Please login and/or register. 2024 NOTE: Soon ALL Technical Sections will be ONLY for registered users. Optionally you can email us forum@mchenrysoftware.com your Name, Company, Location, a Username, and a Password (which you can change) and we will register you and send you a confirmation email.


Register Login