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Abstract

The main goal of this study is to develop a novel multi-body dynamic model for seat-occupant system of a manned spacecraft. The seat of a spacecraft and its components has significant effects on an astronaut’s body during flight mission, where sustained accelerations and impact loads are inevitable. Besides, conducting sustained acceleration and shock loads on the body of astronauts during flight missions is the key factor for health conservation. This study develops a new multi-body dynamic model for seat-occupant system of manned spacecraft to investigate the effects of spacecraft seat design. The astronaut is modelled as a four-jointed rigid link placed on a viscoelastic cushion. The cushion is modelled to present polyurethane foam, which is using in almost all automotive and aerospace applications. The equations of motion are derived and the effects of different parameters are investigated. To verify the developed model, a finite element model is presented to implement the same exact multi-body model. The results show that the presented analytical multi-body model is in good accordance with the finite element model. The effects of different parameters such as foam discretisation, foam thickness and geometry of seat frame on the motion of the system are illustrated. This novel model can be used in designing spacecraft seat to preserve an astronaut’s health. It also can be used in seat control applications and where computational efficiency is necessary.

Keywords

Spacecraft seat-occupant system multi-body model polyurethane foam viscoelastic materials VUMAT subroutine

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Development and verification of a multi-body dynamic model for seat-occupant system of manned spacecraft

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