三种工况下SiC/Al FGM紧凑拉伸试件的力学行为研究

MECHANICS PERFORMANCE STUDY OF SiC/Al FGM COMPACT TENSION SPECIMEN UNDER THREE WORKING CONDITIONS

SiC/Al梯度功能材料各梯度层由不同体积浓度的陶瓷和金属组成,由于材料组分梯度变化,克服了双材料界面的应力突变问题,从而获得优异的使用性能。文中应用Ansys软件和激光云纹干涉法,对具有四个梯度层的SiC/Al梯度功能材料紧凑拉伸试件在三种工况下的力学行为进行研究。通过Ansys分析得出试件裂纹扩展的规律以及裂前4mm处的应变分布,后续实验采集试件随各载荷变化的位移场云纹图,根据位移与条纹级数的关系以及小变形条件下应变与条纹级数关系式,得到梯度功能材料紧凑拉伸试件预制裂纹区的应变分布。通过两种方法相应结果对比分析,得出有关梯度功能材料的裂纹扩展准则的适用性方面的结论;同时,就实验获得的应变测量结果,讨论梯度功能材料的物性变化规律,以及材料组分和梯度层结构对材料整体物性参数的影响。

SiC/Al functionally gradient materials（FGM） have gradient layers made up of different volume concentration ceramic and metal. The large stress changes in the interface of bi-material are avoided in functionally gradient materials because of the gradient of the material property, thus have obtained excellent application performance. Both Ansys and the laser Moire interferometry are applied to study the mechanical behaviors of layered functionally gradient materials compact tension specimen under three engineering conditions, where the experimental means is based on front-wave interferometry principle. Crack propagation behavior and strain distribution in a region that in front of the crack face axe vividly illustrated by Ansys simulation. The fringes obtained by means of the test are used to lead to the strain distribution in front of the crack face through strain and fringe relation. A comparison between experimental Moire fringes and conclusions from Ansys simulation reaches an agreement about the application of crack propagation principle in FGM. Meanwhile this work discusses both the elastic property change tendency in a FGM due to component variation and influences of material components and structure of gradient layers on macro-scope elastic properties of FGM.