【摘要】 针对海洋平台等复杂大型土木工程结构物 ,研究基于振动测试的无损检测方法 ,提出了一套利用结构单元模态应变能特性的新损伤诊断方法。该方法是将结构单元的模态应变能分解为拉压模态应变能和弯曲模态应变能 ,并定义了两个损伤诊断指标 ,即拉压模态应变能变化率 (CMSECR)和弯曲模态应变能变化率 (FMSECR)。模态应变能是通过结构不完备模态振型和结构刚度矩阵计算出的 ,因此 ,可以通过振动测试得到结构单元的两个损伤指标诊断结构的损伤。为了验证本文所提出损伤诊断方法的正确性 ,利用海洋平台有限元模型数值模拟了三个典型的损伤工况。根据损伤诊断结果 ,本文所提方法能够得到较满意的诊断精度 ,具有一定的实际应用价值更多还原

【Abstract】 In this paper nondestructive damage detection (NDD) in large/complex structures is investigated based on vibration monitoring. A new method of damage detection is presented, which utilizes an invariance property of element modal strain ener gy. The theory of NDD for frame type structure is formulated. This method is ba sed on assigning element modal strain energy to two parts, and defines two damage detection indexes. One is compression modal strain energy change ratio (C MSECR), the other is flexural modal strain energy change ratio (FMSECR). The pr esent modal strain energy are obtained by incomplete modal shape and structural stiffness matrix. Structure health monitoring is thus accomplished via monitorin g the elemental CMSECR and FMSECR. Several damage cases are simulated with an of fshore platform numerical model (FEM), and presented to illustrate the utilit y of the proposed method. According to the results, the proposed method is shown to be effective for the complex structural damage detection and has satisfactor y precision.更多还原