How to estimate the fuzzy reliabilitfy of structure of an A-shaped derrick is a problem to be solved after the strengthand reliability of component parts of the derrick are detennined.

• 当求得A形井架工作寿命下的井架构件强度普通可靠度后，如何估计井架结构模糊可靠度，是一个有待探讨的课题。