Techniques from perturbation method and reliability-based design theory are employed to present the practical and effective method for the reliability-based design of gear pairs. The theoretical formulae of reliability-based design of gear pairs are obtained. The corresponding program can be used to obtain the reliability-based design parameters of gear pairs accurately and quickly.

较好地解决了具有独立失效模式的多自由度非线性随机参数振动系统的可靠性灵敏度分析问题．应用四阶矩技术和Edgeworth级数把未知的响应和状态函数的概率分布展开成标准的正态分布的表达式，从而确定了系统的可靠度和可靠性灵敏度，并放松了随机参数的分布概型和激励类型．

Techniques from the perturbation method, the second moment and reliability-based design theory are employed to present a practical and effective method for the reliability-based design of automobile components. The theoretical formulae of reliability-based design of automobile compo-nents are obtained. The reliability-based design methods are employed to develop the reliability design of atttomobile axles and springs. The corresponding program can be used to obtain the reliabilit\-based desien parameters of automobile components accurately and quickly,

在一般随机有限元法的基础上，给出了在随机参数的联合概率密度函数未知的情况下，具有相关失效模式的非线性动态随机结构系统可靠性分析的方法．应用四阶矩技术、最大熵理论、边缘概率分布函数的概念和不完全概率信息理论，解决了多自由度非线性随机结构振动系统的首次超限破坏问题．

This paper proposes the application of reliability-based optimization and robust design methods of a coil tube-spring. The perturbation method, the Edgeworth series, the reliability-based optimization, the reliability sensitivity technique, and the robust design method are employed to present practical and effective approaches of reliability-based optimization and robust design for coil tube-spring with non-normal distribution parameters, on the condition of the known first four moments of the original random variables. Theoretical formulae for reliability-based optimization and robust design are obtained. The respective programmes can be used to obtain the reliability-based optimization and robust design parameters of a coil tube-spring with non-normal distribution parameters accurately and quickly.