用于结构健康诊断的动静结合法及其试验验证

Dynamic and static combining method (DSCM) for structural damages detection and its verification

介绍了一种用于梁式结构的健康诊断方法,该方法以具有较高测试精度的低阶模态参数和静力测试参数为损伤识别量,适用于本构相同的多个结构或构件的健康诊断。具体实施中只选取少量结构作为样本,对其进行静、动力的联合测试,以获得静力、动力参数间的数学回归关系,依此关系对其余的结构仅通过动力测试便可获得等效于静力加载法的健康诊断效果。以12个不同损伤程度的钢桁架结构为试验对象,对其静、动参数的相关性进行了研究。结果表明,桁架的静力刚度和一阶固有频率与桁架的损伤程度密切相关,二者可作为标识桁架损伤的静、动参数。静、动参数对桁架的损伤程度指示明确,规律是损伤越大,静、动参数值越小。采用最小二乘法建立了桁架静、动参数间数学关系式,说明梁式结构的静、动参数密切相关,动静结合法可行。

A structural damage detection method being suitable for beam structures is presented here. The structural lower mode parameters and static test parameters with relatively high precision are used as damage index in this method, which is capable of doing damage detection for a batch of structures or components with same constitutive relation. Only small number of the whole elements needs to be measured both dynamically and statically for regression relationship between static and dynamic parameters; the left elements just need to be measured dynamically and its detection effect is equivalent to that in the static test by using the regression relationship from the previous step. 12 same steel truss models with different damage extents are constructed, and the relationship between static and dynamic parameters of the models has been Studied here. Detailed test results show that the stiffness and the first natural frequency of the structure are closely related with the damage extent, and both the static and dynamic parameters can be adopted to be the truss damage detection index. The two parameters can have a clear indication of the damage, and the regression relationship is that the parameters would be decreased while the damage is worse. Furthermore, the relationship between the two types of parameters can be formulated by least square method, which indicates that DSCM is feasible to beam structures and the two parameters are closely related with each other.