Abstract
Keywords: Finite element of repaired car, crashworthiness, occupant protection, virtual test, crash simulation, unprofessional repair, impact analysis
Unprofessional repairs carried out on a car body significantly affect the quality of structural collapse rating and the safety of occupants. In a well repaired car body using OEMs' own repair methodologies and procedures, occupants have a greater chance of surviving an accident with minor or no injuries. While in unprofessionally repaired vehicles using poor workmanship, the risk of occupants sustaining serious injuries above MAIS 2+ is high. In this modern age of new sophisticated material use and advanced production techniques employed by OEMs, it is increasingly important to emphasize the need to maintain quality repairs, hence assure the survivability of occupants.
This paper contributes to the understanding of this problem and how it could be alleviated through the employment of good calibrated repair workmanship of structural components and assemblies using Finite Element Models (FEM). Using typical inclusion of bad spot welding, irregular pitching, unconnected open sections and missing cell shell structures, the FE analyses show the potential of short comings in the overall performance of the vehicle body structures with capability to cause serious injury to occupants.
The FE analyses also show how one can crash assess a car by virtual testing. A typical case study of poorly repaired car is subjected to frontal impact offset at 40% with collision velocity of 64kph replicating the Euro NCAP protocol and procedures. The virtually tested vehicle was involved in a pole-to-side impact scenario, then repaired and thereafter tested under 40% offset rigid barrier condition. The results show degradation in load paths, diminishing resistance, alternate deformation characteristics and sporadic change of stress within the car body.