The improvement of robust skills for early defect recognition for fixed marine structures is crucial to avoid the possible catastrophe caused by structural degradation. This paper presents an approach for defect recognition based on vibration measurements that is capable of detecting the defect to individual members of offshore jacket platforms, when limited, spatially incomplete modal datum is available. Generally, model reduction is better than modal expansion. Hereof, this paper investigates the developed new defect recognition method using improved dynamic-reduction system. The approach needs only one mode shape. The approach first updates the modal datum. Then, an efficient technique is applied to create a transformation matrix. This matrix is utilized to correct / or refine the nominal eigenvectors so that the updated model is well-matched with the experimental modal data. In this regard and also to conquer the uncertainties between numerically and experimentally identified features, laboratory vibration tests are accompanied on a physical platform model. The efficiency of the approach is validated by different destruction scenarios foreseen on the physical model. The proposed defect recognition approach in conjunction with iterative dynamic reduction approach yields the best defect location and severity estimate. Proposed technique is considered because of practical considerations and expansion of such methodologies would be extremely useful for offshore jacket structure.

增强对固定的海洋结构进行早期缺陷识别的鲁棒技能，对于避免由结构退化引起的可能的灾难至关重要。本文提出了一种基于振动测量的缺陷识别方法，该方法能够在空间有限，空间不完整的模态数据可用的情况下，检测海上护套平台各个构件的缺陷。通常，模型简化胜于模态扩展。因此，本文研究了使用改进的动态还原系统开发的新缺陷识别方法。该方法仅需要一种模式形状。该方法首先更新模态数据。然后，将一种有效的技术应用于创建转换矩阵。利用该矩阵来校正/或完善名义特征向量，以使更新后的模型与实验模态数据完全匹配。在这方面，也为了克服数值和实验确定的特征之间的不确定性，在物理平台模型上进行了实验室振动测试。通过在物理模型上预见的不同销毁方案可以验证该方法的效率。所提出的缺陷识别方法与迭代动态减少方法相结合可产生最佳的缺陷位置和严重性估计。考虑到提议的技术是出于实际考虑，此类方法的扩展对于海上护套结构将极为有用。在这方面，也为了克服数值和实验确定的特征之间的不确定性，在物理平台模型上进行了实验室振动测试。通过在物理模型上预见的不同销毁方案可以验证该方法的效率。所提出的缺陷识别方法与迭代动态减少方法相结合可产生最佳的缺陷位置和严重性估计。考虑到提议的技术是出于实际考虑，此类方法的扩展对于海上护套结构将极为有用。在这方面，也为了克服数值和实验确定的特征之间的不确定性，在物理平台模型上进行了实验室振动测试。通过在物理模型上预见的不同销毁方案可以验证该方法的效率。所提出的缺陷识别方法与迭代动态减少方法相结合可产生最佳的缺陷位置和严重性估计。考虑到提议的技术是出于实际考虑，此类方法的扩展对于海上护套结构将极为有用。所提出的缺陷识别方法与迭代动态减少方法相结合可产生最佳的缺陷位置和严重性估计。考虑到提议的技术是出于实际考虑，此类方法的扩展对于海上护套结构将极为有用。所提出的缺陷识别方法与迭代动态减少方法相结合可产生最佳的缺陷位置和严重性估计。考虑到提议的技术是出于实际考虑，此类方法的扩展对于海上护套结构将极为有用。