HVE White Papers
||EDCRASH (Engineering Dynamics Corporation Reconstruction of Accident Speeds on the Highway)
||EDCRASH is a reconstruction analysis of single- or two-vehicle accidents, including collision. Based on the CRASH model developed at Calspan and extended by NHTSA, EDCRASH also includes several enhancements developed by EDC, including hard spots on the vehicle exterior and an extensive set of run-time diagnostics that help confirm valid results.
EDCRASH primary purpose is to determine impact speed and delta-V (a measure of impact severity) based on accident site and vehicle damage measurements. EDCRASH is also well-suited for collisions with immovable barriers, such as bridge abutments and large trees.
EDCRASH has been validated using the RICSAC collision experiments, a set of 12 well-instrumented staged collisions. Several validation studies have been published in the technical literature.
EDCRASH is a 2-D, 3 degree-of freedom (X,Y,PSI) analysis for each vehicle. For oblique impacts, EDCRASH uses the conservation of linear momentum; for collinear collisions, vehicle damage is used in conjunction with crush stiffness coefficients derived from barrier crash testing. The impact-to-rest phase is analyzed using energy methods and a modified Marquard method allowing for the effects of vehicle rotation and curved trajectories. The impact-to-rest phase may also be confirmed by a trajectory simulation.
If you would like to see an example of how to use EDCRASH, download the Tutorial from the EDCRASH Physics Manual. (Download time for this 1.1 MB Adobe PDF file is about 1 - 5 minutes, depending upon your connection speed.)
- Selectable from HVE's built-in databases, according to Type (Passenger Car, Pickup, Multi-purpose, Van, Truck) Make, Model, Year, Body Style
- Tires selectable from HVE's built-in databases, according to Type (Passenger Car, Light Truck, Heavy Truck, Mobile Home), Manufacturer, Model and Size
- Several Database Sources (Generic, EDC, User and others) for both vehicles and tires
- All data are user-editable
- Complete vehicle model specification published in SAE 950308
- 3-D Terrain Model (from DXF file or several other sources) with user-definable friction for tire-road interaction
- Local Gravitational Constant
- 3-D drag-and-drop positioning of vehicles in the environment
- Wheel Data (% Lock-up, Steer Angle, Rot/Lat Skidding, Pre-impact Braking)
- Simulation Controls (trajectory phase integration timestep and termination conditions)
- Accident History (initial, impact, separation and final/rest positions and velocities)
- Damage Data (profile, CDC, PDOF, delta-V)
- Vehicle Data (dimensions, inertias, stiffness, tire properties)
- Messages (event-related diagnostics)
- Site Drawing (display of all user-entered vehicle positions in the environment)
- Damage Profiles (display of vehicle damage)
- Momentum Diagrams (vector diagram of pre- and post-impact momentum)