The damping of thin-walled composite one-cell beams was theoretically studied. The equations of motion of the beams were derived using Hamilton's principle. A variational asymptotical approach ( VAM) was employed to establish the relationship between sectional force and displacement. The Galerkin's method was adopted to solve the coupled differential equations. Analytical formulas for modal dampings of the beam were derived on the basis of maximum strain energy theory. The theoretical solutions were compared with the results obtained by the finite element analysis. Numerical results of two box beams were obtained, namely, the circumferentially uniform stiffness (CUS) beam and the circumferentially antisymmetric stiffness ( CAS) beam, furthermore the result of one airfoil profile beam was also acquired. The effects of fiber orientations, and sectional aspect ratio and on modal dampings were investigated.%研究单闭室复合材料薄壁梁的结构阻尼特性.基于变分渐进法(VAM)和Hamilton原理,分别建立薄壁梁的截面力位移关系和运动方程；采用Galerkin法对薄壁梁进行自由振动分析；在获得薄壁梁振动模态矢量的基础上,根据最大应变能理论,对薄壁梁的模态阻尼性能进行预测,并且将阻尼预测的结果与现有的有限元计算结果进行对比,验证了该文阻尼分析模型的有效性.进一步针对周向均匀刚度配置( CUS)和周向反对称刚度配置(CAS)两种构型复合材料薄壁箱形梁以及一个翼型截面梁,进行阻尼计算,揭示了纤维铺层角和截面宽高比等参数的影响.
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