基于应力状态参数的韧性材料损伤机理研究  

Damage Mechanism of Ductile Metals Based on Stress State Parameters

作　　者：何敏[1,2] 李付国[1] 

机构地区：[1]西北工业大学材料科学与工程学院,西安710072 [2]徐州工程学院机电工程学院,江苏徐州221008

出　　处：《航空材料学报》2010年第6期80-86,共7页Journal of Aeronautical Materials

基　　金：航空基础科学基金(03H53048)

摘　　要：为研究加载方式对裂纹萌生-扩展的影响机理,推导出米赛斯屈服准则与屈雷斯加屈服准则统一的载荷谱。基于该载荷谱利用内聚单元模型对5052铝合金内部椭圆形脆性相微观视场进行微裂纹萌生扩展研究。利用应力状态参数对不同加载方式下微裂纹的起裂方式和起裂位置进行了分析,结果表明:韧性材料的微裂纹起始于基体内脆性相,宏观基体材料与微观脆性相之间应力状态的不协调是致使裂纹萌生的主要原因。刚度弱化系数预示了微裂纹的起始位置,应力状态参数综合表征了裂纹的类型和起裂方式。在相同形变量时,裂纹萌生难易程度存在差异:双向压缩不易诱发微裂纹而纯剪切较易诱发微裂纹。研究结论与试验结果吻合较好。Loading spectrum,integrating Von-Mises yield criterion with Tresca yield criterion,described the loading state in order to research the effects of loading mode on micro-crack initiation and growth at microscopic scale.A microcosmic view field model containing an elliptical inclusion was investigated in 5052 aluminum alloy and the inclusion was regarded as cohesive elements based on the loading spectrum.The stress state parameters were applied to explore the crack type and the initial location of crack under various load-ing modes.The results show that the microcrack firstly initiates at brittle phase,and the main reason is the inconsistent stress condition between matrix and inclusion.The overall scalar stiffness degradation（SDEG） predicts the crack nucleation location and the stress state parameters comprehensively describe the crack type.The same strain but the difference at crack nucleation shows that diaxial compression loading mode doesn’t easily induce crack and pure shear loading mode is easier to initiate crack than the other loading modes.The analysis results agree with the experimental results.

关 键 词：板料成形 损伤 应力状态参数 内聚元模型 5052铝合金 

分 类 号：TG111.91[金属学及工艺—物理冶金]