碳纤维双边柔性法兰压缩刚度计算方法

Compressive Stiffness Calculation Method for CFRP Bilateral Flexible Flange

综合复合材料细观力学的复合原理、修正复合原理提出了碳纤维(carbon fiber reinforced polymer,CFRP)双边柔性法兰刚度计算方法,基于三维弹性理论推导了复杂铺层法兰的等效材性参数,根据法兰根部的变形协调条件,利用梁弯曲近似微分方程推导了法兰压缩刚度计算表达式。为分析与验证压缩刚度理论模型,基于既有铺层法兰,建立了3组法兰管试件的有限元模型,令管身端部承受均匀分布的压力,求解获得法兰根部的轴向压缩位移继而求得压缩刚度。结果表明,在同样法兰材质和相同荷载作用下,法兰越厚,对应的压缩刚度越小,有限元模型获得的压缩刚度在初始阶段略有增加,在30 MPa左右的压应力时达到稳定,理论模型计算的压缩刚度值则不随荷载变化。3组试件有限元模型与理论模型计算结果误差不超过4%,表明CFRP双边柔性法兰压缩刚度计算方法正确可行。

The stiffness calculation method for bilateral flexible flanges of carbon fiber reinforced polymer(CFRP)is proposed based on the comprehensive principle and modified comprehensive principle of composite materials mesomechanics.The equivalent material property parameters of complex laminated flanges are derived from three-dimensional elastic theory.According to the deformation coordination conditions of the flange root,the calculation formula of the compressive stiffness of the flange is derived by using the approximate differential equation of beam bending.To analyze and validate the theoretical model of compressive stiffness,finite element models of three sets of flanged pipe specimens were established based on existing laminated flanges.The end of the pipe body was subjected to a uniformly distributed pressure to solve for the axial compressive displacement at the root of the flange,thereby obtaining the compressive stiffness.The results show that,under the same flange material property and the same load,the thicker the flange,the smaller the compression stiffness value.The compressive stiffness value obtained by the finite element model increases slightly at the initial stage and becomes stable when the compressive stress reaches about 30 MPa.The compressive stiffness value calculated by the theoretical model does not vary with the load.The error between the finite element model and the theoretical model of the three groups of specimens is within 4%,which indicates the compressive stiffness calculation method of CFRP bilateral flexible flange is correct and feasible.