大型矿用挖掘机传动系统是一个多学科耦合、多系统交互、时变、非线性复杂机械系统，对其进行包括时变失效物理建模、多失效模式下动态可靠性评估和多学科分析在内的可靠性设计优化是保证其安全、可靠的基础。本项目以大型矿用挖掘机传动系统设计优化为工程背景，开展复杂系统基于多工况失效物理建模及集成MDO的时变可靠性设计研究。主要研究内容包括：基于代理模型技术和Bayes信息更新理论的时变失效物理建模方法、基于时变Copula函数与重要样本技术的多失效模式下动态可靠性评估方法、层次型和非层次型优化算法集成的多学科设计优化方法，并以挖掘机传动系统的时变可靠性优化设计实例进行验证；建立大型矿用挖掘机传动系统可靠性评估及多学科可靠性设计优化理论体系。该项目对复杂系统的可靠性评估具有重要意义，对于提高产品设计质量具有实际价值。

Transmission system of large-sized mining excavator is a multidisciplinary coupled, multi-system shared, time-dependent and nonlinear complex mechanical system, time-dependent reliability based design optimization, including physics of failure modeling, dynamic reliability assessment under multi-failure modes, and multidisciplinary analysis, is a primary work ensuring safety, dependability of this complex mechanical systems. The new project proposal is based on reliability based design optimization for transmission system of large-sized mining excavator, and it extends existing research by considering physics of failure modeling under multi loading cases and integrated MDO based time-dependent reliability design optimization. The research mainly includes research on meta-modeling technique and Bayes information updating theory based time-dependent physics of failure modeling, time dependent Copula function and importance sampling approach based dynamic reliability assessment under multi failure modes, hierarchical and non-hierarchical optimization algorithms integrated multidisciplinary design optimization, time-dependent reliability design optimization for excavator transmission system will be analyzed and verified. The reliability assessment and reliability based multidisciplinary design optimization theory system is developed. It may lead to a significance of enhancing reliability of complex system, and bring practical value for improving the quality of the product design.