Title: Soft tissue human thigh and buttock finite element model to simulate vehicle seat cushion indentation

Authors: Gunther Paul; Jason Miller; Jon Pendlebury

Addresses: School of Public Health and Social Work, Queensland University of Technology, Victoria Park Road, Kelvin Grove, Qld 4059, Australia ' Faculty of Science, Engineering and Technology, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria, 3122, Australia ' Ford Motor Company Australia, Research & Development Centre, North Shore Road, North Geelong, VIC 3214, Australia

Abstract: Accurate modelling of automotive occupant posture is strongly related to the mechanical interaction between human body soft tissue and flexible seat components. This paper presents a finite-element study simulating the deflection of seat cushion foam and supportive seat structures, as well as human buttock and thigh soft tissue when seated. The thigh-buttock surface shell model was based on 95th percentile male subject scan data and made of two layers, covering thin to moderate thigh and buttock proportions. To replicate the effects of skin and fat, the neoprene rubber layer was modelled as a hyperelastic material with viscoelastic behaviour. The analytical seat model is based on a Ford production seat. The result of the finite-element indentation simulation is compared to a previous simulation of an indentation with a hard shell human model of equal geometry, and to the physical indentation result. We conclude that SAE composite buttock form and human-seat indentation of a suspended seat cushion can be validly simulated.

Keywords: automotive seats; car seats; seat indentation; cushion deflection; finite element analysis; FEA; modelling; simulation; digital human models; DHM; soft tissue; human thighs; human buttocks; seat cushions; vehicle design; occupant posture; flexible seat components; seat cushion foam; occupant support; seat structures; thigh-buttock surface shell model; hyperelastic materials; viscoelastic behaviour.

DOI: 10.1504/IJHFMS.2014.067179

International Journal of Human Factors Modelling and Simulation, 2014 Vol.4 No.3/4, pp.220 - 232

Received: 24 Jan 2014
Accepted: 16 Jul 2014

Published online: 23 Jan 2015 *

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