复合材料机载天线罩有限元内力计算和屈曲稳定性分析

本文用有限元法计算了复合材料机载天线罩的内力,并对其进行了稳定性分析,得到了均布载荷作用下天线罩的内力和稳定性临界载荷及屈曲模态。文中选用轴对称截锥单元来离散天线罩,在应变向量阵中引入了横向剪切应变,从而考虑了剪切影响。为了避免剪切自锁,刚度的计算采用一点高斯积分法,几何刚度的推导采用Stricklin法。最终将稳定性问题归结为特征值问题。数值算例表明,对于复合材料旋转壳,横向剪切变形使其临界载荷降低;天线罩内力较大的区域集中在头部附近,失稳发生在根部附近,增加根部的厚度可改善天线罩的稳定性。

Internal forces computing and buckling analysis of composite radomes

The internal forces and buckling analysis of composite radome is developed by means of finite element method.The internal forces,the critical load and the buckling mode of radome under uniform pressure are got.The transverse shear strain is introduced into the strain vector to consider the transverse shear effect.To avoid shear lock,the one point GAUSS integral method is used to compute the stiffness.The geometry stiffness is deduced by Stricklin method.The stability problem is generalized to an eigenvalue problem at last.The examples show that the critical load of composite shells of revolution will decrease when considering the transverse shear deformation.About composite radomes,the internal forces are big at the head.But buckling happens at the root.So increasing the thickness of root will improve the stability of radomes.