基于损伤容限设计的机体金属材料力学性能综合表征与评价

Synthetic Characterization and Evaluation of Mechanical Properties for Airframe Metal Based on Damage Tolerance Design

随着结构耐久性和损伤容限设计概念的引入,机体结构设计选材越来越注重材料的损伤容限特性。考虑到材料的使用应力,提出用稳定裂纹扩展阶段da/dN-3ΔK/σb曲线来表征材料的损伤容限特性。对航空常用金属材料的分析结果表明,采用这种表征方法能较为全面地反映材料的损伤容限特性。建立了材料使用应力与疲劳寿命和裂纹扩展寿命的关系图,此图可以用来综合评价材料的静强度、疲劳和损伤容限特性,提高选材的准确性,也可由结构设计要求提出材料的性能指标来指导新材料的研制。

The airframe material selection criterion has paid more attention to the damage-tolerant properties with the establishment of durability and damage-tolerance design principle.Considering the actual bearing stress,the damage-tolerance properties can be characterized by the da/dN-3ΔK/σb curves during crack stationary propagation stage.The damage tolerance properties of the airframe metals are compared by using this method.The compared results show that this characterization could characterize the damage-tolerance properties of materials more comprehensively.The curves of stress vs.total fatigue life and crack propagation are plotted to evaluate the synthetic mechanical properties,and to enhance the accuracy of materials selection.On the other hand,the relationship between material properties and design requirements are established through these curves,this could guide the new material research and development.