Virtual Seat Manufacturing and Testing for FMVSS 202a Backset Prediction

CAE capabilities have long been used for performing static and dynamic structural analysis during the seat design process. More recently, the soft parts of the seat including foams, trim and suspension have also been modeled with CAE. The purpose of this modeling is to better understand the physical phenomena which are involved in the sitting process, to enhance seat design knowledge, and to replace as much physical testing during the design process with virtual, CAE testing.

This paper presents the first part of a multi-phased, both experimental and numerical project. The aim of this first stage is to assess the capabilities of a CAE methodology to predict FMVSS 202a backset. Based on CAD data, a finite element mesh of the seat was built. The mechanical behavior of all parts was characterized through experiments on material samples. The trimming process for the bottom cushion and the backrest were simulated, in order to evaluate the residual stresses resulting from the manufacturing stage.

The resulting seat model was used to simulate the positioning of the SAE J826 dummy into the seat, together with the Head Restraint Measuring Device. The backset value was computed and compared to the experimental one.