An underwater shock loading produces two dangerous effects. The first effect is to destroy a battleship so that it can not continue normal function. The second is to injure onboard crews through dynamic structural responses. Underwater shock and its effects on battleship have been an active research field since World War Ⅱ and some results were introduced. But results of crews survivability against underwater shock loading have not achieved. Recently, there is a growing interest in effects of underwater shock onboard crews.
Underwater shock isolators act to reduce harmful shock loading within tolerance limits of a human body. The problem of optimum design is defined as the selection of isolator parameter that causes the performance index of the system to be optimized.
In this study the limiting performance optimum design problem of a shock isolator using a genetic algorithm with the elitist strategy was formulated for crew safety against an underwater explosion(UNDEX) shock loading. For simplification of the problem, the ship structure-shock isolator-human body coupled system was idealized as one degree-of-freedom system and the UNDEX shock loading was calculated based on the Talyor's air-backed flat plate theory. Additionally, The mechanical driving point impedance of human body model with shock isolator(ISO,5982-1982) is used to solve the optimum design problem. Through numerical examples, the limiting performance curve of the optimum shock isolator was calculated compared with that of the optimum linear shock isolator composed of a spring and a dashpot. Finally, displayed results of comparison one degree-of-freedom with mechanical driving point impedance of human body model with shock isolator.