粘弹加筋层合圆柱壳的阻尼振动和层间应力

Damping Vibration and Interlaminar Stresses of Viscoelastic Stiffened Laminated Cylindrical Shells

应用分层壳理论并在壳厚方向采用二次插值函数推导出粘-弹加筋层合圆柱壳的动力学方程,并得出简支粘弹加筋层合圆柱壳阻尼振动的解。对粘弹层合圆柱壳,所给出的振动频率和结构损耗因子与A.Okazaki的结果吻合良好。分别计算了粘弹加筋层合圆柱壳对应的低阶频率、结构损耗因子和层间横向应力幅值,并分析了粘弹性材料的影响。结果表明,很高的层间横向应力是低频振动中引起粘弹层合圆柱壳分层破坏的主要因素,而采用适当模量的粘弹性阻尼材料将有效地降低层间横向应力的幅值,特别是层间法向正应力的幅值。

Applying the layerwise shell theories and adopting quadratic functions in the shell-thickness direction,the dynamics equations of viscoelastic laminated cylindrical shells with rings and stringers were deduced and the free-vibration solutions for the simple supported and stiffened laminated cylindrical shells was derived.For the laminated cylindrical shells with an unconstrained viscoelastic layer,the results of predicted vibration frequencies and loss factors showthe good agreement with the A.Okazaki'observations.Computing the transverse stress max-value,nondimensional frequencies and loss factors in the shell corresponding to the lower-order models and anaˉlyzing the viscoelastic layer influence on the interlaminar transverse stresses in the shell,the results showthat very high transverse shear stresses are the main factor which leads to the break of laminates for the stiffened laminated cylindrical shells in the lowfrequency vibration,moreover,using a proper modulus viscoelastic layer will effectively decrease the max-value of interlaminar transverse stresses,especially transverse normal stress.