热力耦合作用下复合材料-金属连接结构力学性能分析

Analysisof Mechanical Properties of Composite-Metal Bolted Panel under Thermo-Mechanical Coupling Condition

随着复合材料在飞机结构中应用比例的不断提升,将会出现大量的复合材料-金属混合连接结构。由于材料热膨胀系数的差异性,在极端温度环境下结构将产生较大的热应力。该附加载荷和外部机械载荷产生叠加行为后,对飞机结构强度带来一定影响。本文以壁板级混合结构为研究对象,开展典型多钉壁板结构在热力耦合作用下的力学行为研究。在试验方面设计了室温拉伸、纯温度场、热力耦合三类方案,研究了该壁板结构的热应力分布规律。在仿真方面采用壳-梁组合单元建立了结构有限元模型,由试验结果验证了建模方法的准确性,并进一步分析了热应力对结构静强度的影响。研究表明:热应力会影响以复合材料破坏为主的混合结构承载能力,在本算例中影响程度在6%左右;对金属破坏为主的混合结构承载能力几乎没有影响,但会提前进入塑性变形。

With the continuous increase in the proportion of composite materials used in aircraft structures,a large number of composite-metal hybrid joint structures will appear.Due to the differences in thermal expansion coefficients of materials.hybrid structures will generate significant thermal stress in extreme temperature environments.The superimposed behavior of this additional loads and external mechanical loads has a certain impact on the strength of the aircraft structure.This article focuses on the study of wall panel level hybrid structures and the study of the mechanical behavior of typical multi-bolt struc-ture under thermo-mechanical coupling condition was carried out.In the experimental aspect.three types of test schemes were designed,including room temperature tensile.pure temperature,and thermo-mechanical coupling,to study the distri-bution of thermal stress in this panel structure.In the simulation aspect.the finite model of the structure was established by using the shell-beam combination unit.The accuracy of the modeling method was verified by test results,and the influence of thermal stress on the static strength of the structure was further analyzed.The results show that thermal stress will affect the bearing capacity of hybrid structures dominated by composite failure.and the degree of influence is about 6%in this ex-ample.It has almost no effect on the bearing capacity of hybrid structures dominated by metal failure.but it will enter plastic deformation in advance.