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Crack detection procedures by different modal parameters are analyzed for identitying a crack and its location and magnitude in a jacket plafform. The first ten natural frequencies and modal shapes of the jacket models are obtained by numerical experiments based on NASTRAN Code. A crack at different locations and of different magnitudes is imposed in the model at the underwater beams. Then, the modal evaluation parameters are calculated numerically, to illustrate the evaluation of modal parameter criteria used in jacket crack detection. The sensitivities of different modal parameters to different cracks are analyzed. A new technique is presented for predicting the approximate location of a breakage in the absence of the data of an intact model. This method can be used to detect a crack in underwater menbers by use of incomplete mode shapes of the top members of the jacket. 相似文献
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针对海洋平台损伤检测方法中需要未损伤模型参数的不便，提出了一种相对频率变化量的方法。对不同类型构件的损伤及同一类型构件在不同位置损伤的情况，进行结构模态分析，研究平台结构的固有频率对损伤、损伤位置和损伤程度的敏感性，以及平台质量变化对频率的影响。利用两次测量的相对频率变化量，可以发现损伤的存在，并进行损伤的初步定位。 相似文献
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