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采用简单有效的方法对复杂的飞机结构进行损伤容限评定具有重要的意义,提出一种简单有效的应力强度因子获取方法,并结合损伤容限分析的一般流程,分析某机身框地板梁缘条含裂纹修补结构的疲劳寿命及使用寿命期内结构的剩余强度。根据机身框地板梁结构受载特点建立简化的分析模型,计算单位载荷时不同长度下裂纹尖端应力强度因子,再由结构边界载荷与应力强度因子的关系确定无量纲应力强度因子;根据损伤容限分析方法编制程序,计算结构在飞行载荷谱下从初始裂纹扩展到临界长度的寿命及各裂纹长度下结构的剩余强度,给出结构检查间隔。结果表明:结构修补后的疲劳寿命及剩余强度均满足损伤容限设计要求。本文给出的损伤容限分析过程及方法可应用于工程中类似结构的损伤容限评定。
It is of great significance to use simple and effective method to evaluate the damage tolerance of complex aircraft structures. A simple and effective way to obtain the stress intensity factor is proposed. Combined with the general flow of damage tolerance analysis, Article fatigue life with crack repair structure and residual strength of the structure during life. According to the load characteristics of the floor beam structure of the fuselage frame, a simplified analytical model was established to calculate the stress intensity factor of the crack tip under unit load with different length. Then the dimensionless stress intensity factor was determined by the relationship between the structure boundary load and the stress intensity factor. Limit analysis method to calculate the structure of the structure in the flight load spectrum from the initial crack growth to the critical length of life and the length of each crack length of the residual strength of the structure to give structural inspection interval. The results show that the fatigue life and residual strength of the repaired structure meet the requirements of damage tolerance design. The damage tolerance analysis procedure and method presented in this paper can be applied to damage tolerance assessment of similar structures in engineering.