To characterize the uncertainty and fuzziness in offshore structural inspection, probability of detection (POD) must be determined. This paper presents the expressions for the POD of four different damage forms mainly...To characterize the uncertainty and fuzziness in offshore structural inspection, probability of detection (POD) must be determined. This paper presents the expressions for the POD of four different damage forms mainly existing in offshore structures. The fuzzy-set theory is applied to estimate human errors through the definition of inspection quality. Expressions of inspection quality are achieved. To verify the validity and correctness of the expressions, the data from an offshore platform field inspection of evaluation results of human errors affecting inspection quality are used to estimate the parameters of the POD. The results show that the present models can provide basis for further study of ofTshore structural inspection reliability.展开更多
In general, every system is in one of the three states： normal, abnormal, or failure state. When the system is diagnosed as abnormal state, it needs predictive maintenance, lfthe system fails, an identical new one wi...In general, every system is in one of the three states： normal, abnormal, or failure state. When the system is diagnosed as abnormal state, it needs predictive maintenance, lfthe system fails, an identical new one will replace it. The predictive maintenance cannot make the system ＂as good as new＂. Under these assumptions, the reliability index and the inspection-replacement policy of a system were studied. The explicit expression of the reliability index and the average income rate （i.e., the long-run average income per unit time） are derived by using probability analysis and vector Markov process method. The criterion of feasibility for the optimal inspection-replacement policy under the maximum average income rate is obtained. The numerical example shows the optimal inspection-replacement policy can raise the average income rate when the optimal inspection-replacement policy is feasible.展开更多
Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian...Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.展开更多
文摘To characterize the uncertainty and fuzziness in offshore structural inspection, probability of detection (POD) must be determined. This paper presents the expressions for the POD of four different damage forms mainly existing in offshore structures. The fuzzy-set theory is applied to estimate human errors through the definition of inspection quality. Expressions of inspection quality are achieved. To verify the validity and correctness of the expressions, the data from an offshore platform field inspection of evaluation results of human errors affecting inspection quality are used to estimate the parameters of the POD. The results show that the present models can provide basis for further study of ofTshore structural inspection reliability.
基金Project supported by the National Hi-Tech Research and Develop-ment Program (863) of China (No. 2005AA505101-506)theNational Natural Science Foundation of China (No. 50477030)
文摘In general, every system is in one of the three states： normal, abnormal, or failure state. When the system is diagnosed as abnormal state, it needs predictive maintenance, lfthe system fails, an identical new one will replace it. The predictive maintenance cannot make the system ＂as good as new＂. Under these assumptions, the reliability index and the inspection-replacement policy of a system were studied. The explicit expression of the reliability index and the average income rate （i.e., the long-run average income per unit time） are derived by using probability analysis and vector Markov process method. The criterion of feasibility for the optimal inspection-replacement policy under the maximum average income rate is obtained. The numerical example shows the optimal inspection-replacement policy can raise the average income rate when the optimal inspection-replacement policy is feasible.
基金Project BK2008128 supported by the Natural Science Foundation of Jiangsu Province
文摘Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.
