Integration of a Dynamic Human Body Model within the NVH-Analysis of the Complete Passenger Car

A particular challenge in the development of passenger cars by means of numerical simulation consists in the prognosis of the vibration comfort of the passenger. Reason for this are the nonlinear and frequency-dependent properties of human body and seat. The integration of the occupied seat in the complete passenger car is principally feasible, but increases the computational efforts for NVH-analyses dramatically. Reason for this is the nonlinear seating process which must be calculated for the determination of the operating point prior to the actual NVH-analysis. As a workaround a simplified method was developed. In a first step a separate analysis of the occupied seat is performed with the tool CASIMIR/Automotive. After that the systems is condensed to the relevant degrees of freedom in the form of a matrix. The integration in the complete passenger car is realized via the connections at the real coupling points, i.e. via seat rail, feet and hands. For the direct evaluation in the complete passenger car the matrix includes further output points, e.g. head and torso. A detailed visual evaluation of individual operating vibrations can be carried out subsequently in the post-processor by the direct combination of the simulation of the complete passenger car and the occupied seat. The developed method was applied and validated within the scope of a pilot project. Compared to existing methods this new approach offers additional information content, since all relevant components can be simulated already at an early stage so that statements as to the vibration comfort and possible hardware optimizations can be made.