Advanced Methods in Crash Safety Testing

Abstract

"Current automotive market has to follow legislative that has been established in order to ensure minimum car safety. Nowadays two types of physical tests exist - mandatory and consumer’s tests. Major players use both virtual and physical testing during development to meet criteria of those tests. This work is to give an overview of current methodology and subsequently propose a new advanced approach of combined virtual and physical testing. KEYWORDS Crash test, finite element method, passive safety, DYCOT, ALIS, biomechanical loads INTRODUCTION This work is to give an overview of current approaches regarding the used methodology in the field of passive safety, ie. crash tests. It is based on experience gained in the Active Lateral Impact Simulator (ALIS) project and describes complete virtual and physical process. The main focus has been set to the fine-tuning of the boundary conditions and loading of the system in order to ensure correct biomechanical loads. ALIS process Usually at the very beginning of any project, no physical prototype exists. The car exists only in virtual world; both design (CAD) and simulation (CAE) combine together to develop the latest version. Later as the development goes on, physical testing takes over and it is input-dependent on virtual simulations. The whole process is combination of several testing loops of virtual and physical testing. Design of Experiment (DoE) The main objective is to develop a virtual method that would allow reducing full side crash into sled crash via ALIS, defining complete ALIS setup and give highly accurate results, while reducing costs and time. The DoE method is advanced mathematical method that uses n-dimensional mathematical surface for response values prediction based on combination of input parameters. The aim is to get ideally perfect match between full crash model as given at the beginning of the project and ALIS reduced model. Amount of input parameters is very often high. One of the ways how to put up with them might be Design of Experiment (DoE) with response surface creation or “step-by-step” iteration with subsequent physical validation. Such method would reduce number of runs and predicts multiple results based on input parameter combinations. Such pulses have to fulfill feasibility criteria of the cylinders and catapult. In every single project there is no way that all responses will match perfectly the ideal (original) curves, responses respectively. It is always a trade-off that has to be done with the respective subject usually customer, where should be the focus of the project. CONCLUSION This application and approach is very specific, unique and never will be the same. As a result of the DoE work with the pulses, the outcome is highly likely to be very accurate and it will be the next phase of the project to validate and correlate such procedure with ALIS physical testing and subsequently with full vehicle crash."