Input Power Flow Charateristics of Cylindrical Shell with Axisymmetric Cracks
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摘要: 广泛应用于船舶与海洋工程等领域的圆柱壳结构因冲击、腐蚀、交变载荷等外力作用下常出现裂纹损伤,因此,对含裂纹的圆柱壳结构的动态特性进行研究具有重要意义。对含有环向轴对称表面裂纹的无限长圆柱壳的振动与输入功率流特性进行研究,将壳体中的表面裂纹模拟为线弹簧,运用线弹性断裂力学,考虑到裂纹的张开、滑移和撕裂三种状态,建立了裂纹区域的局部柔度矩阵。分析了在周向线力作用下圆柱壳在呼吸模式下的振动与波传播特性,并讨论了壳体中的输入能量流与裂纹参数数和结构参数之间的联系。结果表明裂纹的存在改变了壳体中的振动波和能量的传播特性,裂纹的位置和深度与功率流特性密切相关。Abstract: Cylindrical shell is widely adopted in the field of maritime industry. Cracks are frequently occurred due to the external forces such as impact, corrosion and alternate load, so that research on the dynamic characteristic of cylindrical shell with cracks is evidently of interest to design work. In this paper, the input power flow characteristics of infinite cylindrical shells with circumferential axissymmetric surface cracks are focused. The vibration of the shell is described by FlUgge's shell equation. The crack is modeled as line spring. In consideration of the three states of crack, the local compliance matrix at the cracked region is deduuced by using the fracture mechanics. The axisymmetric vibration and wave propagation of the cracked shell is analyzed under the excitation of the linedistributed force. The relationships between the input power flow and the crack parameters along with the shell parameters are discussed. The results demonstrate that the presence of crack changes the power flow characteristics. The power flow is close related to the location and depth of the crack.
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Keywords:
- power flow characteristic /
- cylindrical shell /
- crack /
- vibration wave /
- local flexibility
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