Optimal frame geometry of spacecraft seat based on multi-body dynamics modelling

Design of spacecraft seat which preserves astronaut׳s safety against sustained acceleration and impact loads is presented. A novel multi-body dynamics model of seat–occupant system of manned spacecraft is developed. The astronaut is modelled as a four rigid jointed links seated on polyurethane cushion and is restrained with harness to avoid undesired motions. To guarantee safety of astronaut, injury biomechanics is used to design the seat. The top priority of this study is to find an optimal design to minimize injuries of astronaut׳s neck and head by using a multi-body dynamics model of the seat–occupant system. The design variables are considered to be seat geometric parameters. Also, sensitivity analysis has been performed to evaluate the sensitivity of injuries to impact load and astronaut׳s anthropometry. In the end the results indicate the optimal geometry of seat by using neck injury index and head injury index through single objective and multi-objective optimization processes. The results can help designers to design spacecraft seat to ensure the safety of astronauts during flight mission. The results also determines of sensitivity of injuries to impact conditions and mass and height of astronaut. •Astronaut is modelled as a four rigid jointed links seated on polyurethane cushion.•Seat geometry is determined to minimize injuries to occupant׳s neck and head.•Head and neck are very sensitive to impact amplitude and peak time, respectively.•Both head and neck injuries are not sensitive to total impact time.•Injuries are very sensitive to astronaut׳s mass while the height is not important.