Numerical simulation and structural optimization of automotive seat static comfort based on human-seat coupled model

Seating comfort is an essential aspect of vehicle ergonomics, as prolonged sitting often leads to discomfort and even musculoskeletal disorders. This study aims to optimize automotive seat comfort by analyzing the biomechanical responses of human soft tissues under different foam hardness combinations. Through finite element simulation, a seat coupling model was established to study static comfort and analyze the stress and strain distribution in three anatomically vulnerable regions: the ischial tuberosities, femoral areas, and lumbar intervertebral discs, across 25 combinations of upper and lower foam hardness. A Pareto-based multi-objective optimization method was utilized to balance pressure distribution and structural support. The results indicate that foam hardness is a critical determinant of internal tissue deformation and pressure concentration. Specifically, while increased hardness is associated with greater structural support, it also elevates localized stress. Conversely, softer foams, despite offering improved pressure relief, may compromise support stability. Therefore, a systematic analysis of different foam hardness combinations was conducted. The optimal foam hardness configuration strategy outperformed all other tested combinations, achieving a favorable balance between support and comfort. Compared to the initial design, the optimized configuration reduced peak stress and strain in the buttocks and thighs by up to 8.1%, 3.0%, 7.8%, and 2.4%, respectively. In addition, it increased contact area and lowered maximum pressure. The findings provide quantitative guidance for optimizing foam selection, contributing to enhanced seat comfort and reduced risk of pressure-induced injuries.