一个基于孔洞演化机制的韧性断裂预测模型

发布时间：2018-07-14 21:51

【摘要】：在韧性断裂中微观孔洞演化机制的基础上,提出了一个基于孔洞演化机制的非耦合型韧性断裂预测模型.模型充分考虑了两种典型的孔洞演化机制:孔洞的长大机制和孔洞的拉长扭转机制.该模型引入了三个具有不同物理意义的材料参数:材料对不同孔洞演化机制的敏感度、应力状态敏感度系数和材料的损伤阈值,并使用等效塑性应变增量表征其对韧性损伤累积过程的驱动作用.为了使模型可以更好地反映三维应力状态对材料韧性断裂性能的影响,将该模型从主应力空间转换到由应力三轴度、罗德参数和临界断裂应变构成的三维空间,得到了由模型确定的三维韧性断裂曲面,并研究了相关参数对三维韧性断裂曲面及平面应力二维韧性断裂曲线的影响.利用5083-O铝合金、TRIP690钢和Docol 600DL双相钢三个典型的轻质高强板材的韧性断裂数据验证了该模型对不同材料和不同应力状态的适用性和准确性.
[Abstract]:Based on the evolution mechanism of microvoids in ductile faults, a prediction model of uncoupled ductile faults is proposed. The model fully considers two typical mechanisms of pore evolution: the growth mechanism and the elongating and torsional mechanism of the hole. The model introduces three material parameters with different physical meanings: the sensitivity of materials to different pore evolution mechanisms, the sensitivity coefficient of stress state and the damage threshold of materials. The equivalent plastic strain increment is used to characterize its driving effect on the ductile damage accumulation process. In order to better reflect the effect of the three-dimensional stress state on the ductile fracture properties of the material, the model is transformed from the principal stress space to a three-dimensional space composed of stress triaxiality, Luo De parameters and critical fracture strain. The three-dimensional ductile fracture surface determined by the model is obtained, and the influence of related parameters on the three-dimensional ductile fracture surface and two-dimensional ductile fracture curve of plane stress is studied. The ductile fracture data of 5083-O aluminum alloy trip690 steel and Docol 600DL dual phase steel are used to verify the applicability and accuracy of the model to different materials and different stress states.
【作者单位】：北京科技大学机械工程学院;美国俄亥俄州立大学精密成形中心;
【分类号】：TG115.57

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