It is safer for common components to use normal distribution, and it is more exact for very important components to use logarithmic normal distribution or Weibull distribution.

• 对一般构件来讲，应力和强度采用正态分布是合理的，且偏于安全；对可靠度要求很高的构件来讲，建议采用对数正态分布或威布尔分布。