چكيده به لاتين
Manned spacecraft mission for sending human to space, is a complex procedure depends on many design parameters. Since involving human body, the importance of the mission is too much. The main goal is to preserve health of the astronaut to avoid mission disruption. To place the occupant, a seat is embedded in manned spacecraft. In designing the seat, factors such as shock loads, sustained accelerations and vibration loads play key roles. This study tries to present the procedure of spacecraft seat in a way that maintain safety and health of astronaut. To this aim, injury biomechanics has been employed. Injury biomechanics implement injury index to evaluate injuries to human body organs. These indices take body dynamics as inputs and evaluate the injury to that organ.
To predict the dynamics of human body during space missions, multibody dynamics approach is implemented. The goal of these model is to predict the dynamic response of body due to shocks and vibrations during mission. One of the presented models is a human body with solid spine and the other one is with flexible spine. The developed seat-occupant model is placed on a polyurethane foam as seat cushion and harnessed with seatbelt. The main frame forms the geometry of seat and the cushion is located on this frame. This model has been verified using finite element model and previous studies. Also, experimental studies has been practiced using a fabricated seat, dummy, cushion and seatbelt and shock is exposed to the system by shaker and the motion is recorded using sensors for comparison sakes.
The presented model has been used for minimizing injuries to head, neck and spine during space mission and the optimum geometry of seat frame is obtained in each case. The Pareto front from multi-objective optimization has been also captured.
Sensitivity analysis is also employed to assess the effects of different seat parameters on injury evaluation. Parameters such as seat frame geometry, seat cushion, seatbelt, input load and astronaut’s anthropometry is investigated. Presented studies are finally applied for designing Iranian spacecraft seat design. First, seat isolators has been designed based on exposed shocks and vibrations. Then, to minimize the occupant injury, the optimum seat frame geometry is assessed and the seat frame material is investigated using finite elements. Finally, the reliability of the system is evaluated.
