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对于纤维增强复合材料,一般都需要用材料的三个甚至六个破坏实验的结果,来给出复合应力状态下的破坏准则(如Tsai-Hill准则需要三个实验结果;Tsai-Wu准则需要六个实验结果)。本文从偏轴拉伸实验的观察分析中得出:在非单向拉伸应力状态下,纤维增强复合材料的破坏可以认为是由基体控制的。即,基体首先破坏,继而造成整个材料的破坏。据此,提出了以基体破坏来判定材料破坏的破坏准则。采用树脂系统基体时,由于树脂的拉伸强度与剪切强度相近,并在树脂纯扭转实验中可观察到明显的与试样轴成45°的残留断面,故认为:用最大应力理论来判定基体的破坏是适合的。这样,只需知道组份材料的性能和组份含量,就完全可以给出材料在复合应力状态下的破坏准则,节省做三个、甚至六个实验所耗费的精力和费用。
For fiber-reinforced composites, three or even six failure experiments of the material are usually required to give the failure criterion under complex stress conditions (for example, the Tsai-Hill criterion requires three experimental results; the Tsai-Wu criterion requires six Experimental results). From the observation and analysis of the off-axis tensile test, we conclude that the failure of fiber reinforced composites can be considered as controlled by the matrix under non-uniaxial tensile stress. That is, the matrix breaks down first, which in turn causes the destruction of the entire material. Based on this, the failure criterion of material failure is proposed based on the matrix failure. When using the resin system substrate, the tensile strength of the resin is similar to the shear strength, and a clear residual cross-section of 45 ° from the sample axis can be observed in the pure torsion test of the resin. Therefore, the maximum stress theory is used to determine The destruction of the matrix is suitable. In this way, knowing the properties of the component materials and the component content can completely give the failure criterion of the composite under the stress of the composite state, saving the effort and expense of doing three or even six experiments.