基于应力强度因子评估WC_P形状对WC_P/Fe复合材料热疲劳裂纹扩展行为的影响

Effect of WC_P shape of WC_P/Fe composites on thermal fatigue crack propagation behavior based on stress intensity factor

应力强度因子在断裂力学中广泛应用于预测由远程载荷或残余应力引起的裂缝尖端附近应力状态。本文基于平面应力条件下应力强度因子建立WC P形状与其尖端应力之间的规律,利用有限元分析软件对含不同形状WC P的WC P/Fe复合材料的热应力进行模拟仿真,研究WC P形状对WC P/Fe复合材料热疲劳裂纹扩展行为的影响。研究结果表明,WC P的形状显著影响应力强度因子,进一步影响WC P/Fe复合材料的热疲劳裂纹扩展行为。含球状和不规则状WC P的WC P/Fe复合材料的极限抗压强度分别约为460 MPa和370 MPa。含不规则状WC P的WC P/Fe复合材料因应力集中而容易产生脆性开裂现象。通过热震实验进行验证,发现实验结果与模拟仿真结果相近,说明有限元法的准确性,同时为WC P/Fe复合材料的热疲劳裂纹扩展行为研究提供科学依据和理论基础。

The stress intensity factor is used in fracture mechanics to predict the stress state near the tip of a crack caused by a remote load or residual stresses.In this paper,the law between WC P shape and its tip stress was established in a finite plate under uniaxial stress based on stress intensity factor,the thermal stress of WC P/Fe compo-sites with different particle shapes were simulated through finite element analysis software,the effect of WC P shape on the thermal fatigue crack propagation behavior of WC P composites was studied.The results show that the WC P shape significantly affects the stress intensity factor and the thermal fatigue crack propagation behavior of WC P/Fe composites.The ultimate compressive strength of WC P/Fe composites with spherical particles and irregular ones are 460 MPa and 370 MPa,respectively.The WC P/Fe composites with irregular particles are prone to break due to stress concentration resulting in generating brittle cracking.The thermal shock test was used to verify the simulation results,finding that the experimental results are similar to the simulation results,which confirms the correctness of finite element simulation,and provides a scientific and theoretical basis for the study of thermal fatigue crack propagation behavior of WC P/Fe composites.