一、设计基准期的含义人们在工作实践中发现,工程的失效概率(即工程的事故率)P_f与工程的使用年限t有关,一般具有如图1所示的关系。图1中的曲线,明显地把使用年限t分为三个时段,三个时段的失效性质是有区别的,兹分述于下。 1.第一时段称为早期失效率DFR(Decreasing Faiture Rate)。早期失效的特点是失效率非常高,但随着工程运行时间的增加,失效率迅速下降。在这一时段失效的原因,主要 First, the meaning of the design base period People in the work experience found that the project failure probability (that is, the project accident rate) P_f and the service life of the project t, generally has the relationship shown in Figure 1. The curve in Figure 1 clearly divides the useful life t into three periods, and the failure characteristics of the three periods are different and are described below. 1. The first period is called DFR (Decreasing Faiture Rate). Early failure is characterized by a very high failure rate, but the failure rate drops rapidly as the uptime of the project increases. The reason for failure during this period, mainly