针对具有多种失效模式机械零部件的寿命评估问题，分析零部件与其各种失效模式之间的失效逻辑关系，研究具有多种失效模式零部件的失效行为表达方法。在此基础上，分别以连续型变量和离散型变量为寿命度量指标，建立具有多种失效模式零部件的寿命概率分布模型，给出多种失效模式零部件的失效累积分布函数与失效概率密度函数以及可靠度、失效率与平均寿命计算模型，研究零部件的寿命概率分布特征以及可靠度与失效率的变化规律。研究表明，具有多种失效模式零部件的失效概率大于任一种失效模式所对应的失效累积概率，其寿命概率密度呈现出“早期较高、然后先减小后增大、最后又降低”的变化趋势，同时，零部件的平均失效寿命小于任一种失效模式所对应的平均寿命。

As for the problem of life prediction of mechanical components with multiple failure modes,the failure logistical relationship between the component and its failure modes is analyzed,and the method for describing the failure behavior of component with multiple failure modes is studied. Then,with the continuous variable and discrete variable as the life parameter respectively,the life probability distribution models of component with multiple failure modes are developed. The cumulative distribution function and probability density function of life of component are derived and the models of reliability,failure rate model and mean time to failure of component are also derived. The life probabilistic characteristics of component with multiple failure modes and the rules that the reliability and failure rate changes are studied. The results show that for the components with multiple failure modes,the failure probability of component is more than the failure probability corresponding to each one of its failure modes,and as the life parameter increases the failure probability density of component presents the rule that it is high in the early failure period,and then decreases first and after that increases,finally decreases. And the mean time to failure of component is less than that corresponding to each one of its failure modes