基于三维弹性理论的任意铺层FRP管热变形及残余应力计算方法

Calculation method of thermal deformation and residual stress of arbitrarily laminated FRP tube based on three-dimensional elastic theory

为了解决纤维增强树脂复合材料(FRP)圆管在工程中热变形和热残余应力的问题,提出了一种针对任意铺层FRP圆管等效热膨胀系数和热残余应力的计算方法,该方法是综合考虑了层合效应、各向异性材料三维本构关系的三维弹性理论。通过与本文试验和ANSYS数值模型的多组数据进行对比分析,验证了理论的正确性。并以此理论模型为基础,首先对多种铺层FRP圆管等效热膨胀系数进行研究,其次结合Hashin失效准则的强度比方程,对由热残余应力引起FRP圆管强度失效进行分析。结果表明:FRP圆管铺层角度对等效热膨胀系数的影响在热缩阶段、热胀阶段表现不同,且存在等效热膨胀系数为0的铺层方式;径厚比仅对等效径向热膨胀系数影响较大,对等效轴向热膨胀系数无影响;温差大小及温差方向影响FRP圆管的破坏模式及破坏位置,热残余应力引起的FRP圆管的强度破坏均为基体破坏。

In order to solve the problems of thermal deformation and thermal residual stress of fiber reinforced polymer(FRP)circular pipe in engineering,a calculation method of equivalent thermal expansion coefficient and thermal residual stress of FRP tube with arbitrary ply was proposed.This method is a three-dimensional elastic theory considering lamination effect and three-dimensional constitutive relationship of anisotropic material.The correctness of the theory was verified by comparing and analyzing with multiple groups of data of the test and ANSYS numerical model in this paper.Based on this theoretical model,firstly,the equivalent thermal expansion coefficients of many kinds of laminated FRP circular pipes were studied.Secondly,combined with the strength ratio equation of Hashin failure criterion,the strength failure of FRP tube caused by thermal residual stress was analyzed.The results show that the influence of FRP tube ply angle on the equivalent thermal expansion coefficient is different in the thermal shrinkage stage and thermal expansion stage,and there is a laminated mode with zero equivalent thermal expansion coefficient;The diameter thickness ratio only has a great influence on the equivalent radial thermal expansion coefficient,but has no influence on the equivalent axial thermal expansion coefficient;Temperature difference and direction affect the failure mode and location of FRP tubes.The strength failure of FRP tubes caused by thermal residual stress is matrix failure.