摘要
薄壁圆柱壳流体冲击振动响应是一个复杂的流固耦合(FSI)动力学问题,对于薄壳状态监测与缺陷识别具有重要意义.基于Flügge壳体应力理论,得到壳体运动的高阶偏微分方程组(PDE),利用波传播方法获得圆柱壳系统振动响应.将壳体周围流体定义为理想声学介质,通过亥姆霍兹方程描述声压场,得到流固耦合条件下的薄壁圆柱壳受迫振动响应演变规律.针对薄壳裂纹损伤识别问题,基于断裂力学理论建立局部柔度矩阵,结合呼吸型线弹簧模型(LSM),构造裂纹附近应力及位移连续条件,获得含裂纹损伤充液圆柱壳的振动响应,进而给出一种基于振动能量流的裂纹损伤识别方法.研究结果表明:充液圆柱壳耦合系统在非线性激励下,位移响应在沿轴向、周向和径向的传播特性差异明显;裂纹的存在会导致结构局部柔度的降低和耦合系统固有频率下降;归一化输入功率流能够有效地对充液圆柱壳耦合系统进行结构裂纹损伤识别.研究结果可为充液薄壳振动响应方面的研究提供有益参考,也可为流固耦合条件下的结构裂纹损伤识别方面提供技术支持.
The vibration responses of thin cylindrical shells subjected to shock waves from fluid is a complex fluid-structure interaction(FSI)issue,and is of important significance to the state monitoring and damage recognition for thin shells.Based on the Flügge shell stress theory,the high-order partial differential equations(PDEs)of thin-shell motion are set up,and the vibration responses of the system are obtained by the wave propagation method.The peripheral fluid is defined as an ideal acoustic medium,and the acoustic pressure field is described by the Helmholtz equation.According to the above hypothesis,the forced vibration response and evolution regularities for thin cylindrical shells considering the fluid-structure interaction are acquired.For crack damage recognition of thin shells,the partial flexibility matrix is constructed based on fracture mechanics principles,and in combination with the breathing linear spring model(LSM),the adjacent stress and displacement conditions are built.Consequently,the forced vibration responses of thin liquid-filled cylindrical shells with cracks are obtained,and a vibration-power-flow-based crack damage recognition method is presented.The results show that under nonlinear excitations,the displacement responses in the radial,axial and circumferential directions of a thin liquid-filled cylindrical shell are apparently different.Hysteresis is observed for the peak values of radial and axial displacements.The radial displacement contains more peak values,and is more closely related with the impulse excitation from fluid.The crack can decrease the partial flexibility and the natural frequency of the system,and change the power flow characteristics of the FSI system.The transmission coefficient of vibration wave decreases with the increase of crack depth.The normalized input power flow can recognize the crack damage of thin liquidfilled cylindrical shells.This research can not only provide useful references to the modeling of vibration responses for thin liquid-filled shells,but also
作者
朱吟龙
谭大鹏
李霖
郑帅
Yinlong Zhu;Dapeng Tan;Lin Li;Shuai Zheng(Key Laboratory of E&M,Ministry of Education&Zhejiang Province,Zhejiang University of Technology,Hangzhou,310014)
出处
《固体力学学报》
CAS
CSCD
北大核心
2019年第1期51-73,共23页
Chinese Journal of Solid Mechanics
基金
国家自然科学基金(51775501)
浙江省杰出青年科学基金(LR16E050001)资助
关键词
流固耦合
薄壁圆柱壳
振动响应
损伤识别
fluid-structure interaction
thin cylindrical shell
vibration response
crack damage recognition
