The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy （IMSE） meth...The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy （IMSE） method for detecting damage in offshore platform structures based on a traditional modal strain energy method （the Stubbs index method）. The most significant difference from the Stubbs index method was the application of modal frequencies. The goal was to improve the robustness of the traditional method. To demonstrate the effectiveness and practicality of the proposed IMSE method, both numerical and experimental studies were conducted for different damage scenarios using a jacket platform structure. The results demonstrated the effectiveness of the IMSE method in damage location when only limited, spatially incomplete, and noise-polluted modal data is available. Comparative studies showed that the IMSE index outperformed the Stubbs index and exhibited stronger robustness, confirming the superiority of the proposed approach.展开更多
The tradeoff between sensitivity and detection range(maximum and minimum stretchability)is a key limitation in strain sensors;to resolve this,we develop an efficient and novel strategy herein to fabricate a highly sen...The tradeoff between sensitivity and detection range(maximum and minimum stretchability)is a key limitation in strain sensors;to resolve this,we develop an efficient and novel strategy herein to fabricate a highly sensitive and stretchable strain sensor inspired by the membrane-shell structure of poultry eggs.The developed sensor comprises a soft and stretchable surface-grafting polypyrrole(s-PPy)film(acting as the membrane)and a brittle Au film(acting as the shell),wherein both films complement each other at the electrical and mechanical levels.Au forms cracks under strain contributing to its high sensitivity and low detection limit,and s-PPy can bridge Au cracks and increase stretchability which has not been used in strain sensors before.The surface-grafting strategy not only enhances interface adhesion but also tunes the brittle property of native PPy to render it stretchable.Utilizing the synergetic effect of the membrane-shell complementary structure,the strain sensors achieve ultrahigh sensitivity(>10^(7)),large stretchability(100%),and an ultralow detection limit(0.1%),demonstrating significant progress in the field of strain sensors.The membrane-shell(Au/s-PPy)-structured strain sensor can successfully detect finger motion,wrist rotation,airflow fluctuation,and voice vibration;these movements produce strain in the range of subtle to marked deformations.Results evidence the ultrahigh performance and bright application prospects of the developed strain sensors.展开更多
基金Supported by the National Natural Science Foundation of China （51209189, 51379196）, and the Natural Science Foundation of Shandong Province （ZR2013 EEQ006, ZR2011 EL049）
文摘The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy （IMSE） method for detecting damage in offshore platform structures based on a traditional modal strain energy method （the Stubbs index method）. The most significant difference from the Stubbs index method was the application of modal frequencies. The goal was to improve the robustness of the traditional method. To demonstrate the effectiveness and practicality of the proposed IMSE method, both numerical and experimental studies were conducted for different damage scenarios using a jacket platform structure. The results demonstrated the effectiveness of the IMSE method in damage location when only limited, spatially incomplete, and noise-polluted modal data is available. Comparative studies showed that the IMSE index outperformed the Stubbs index and exhibited stronger robustness, confirming the superiority of the proposed approach.
基金the National Key Research and Development Program(2018YFA0703200 and2016YFB0401100)the National Natural Science Foundation of China(21573277,51503221 and 21905199)+1 种基金Tianjin Natural Science Foundation(19JCJQJC62600 and 194214030036)the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(QYZDB-SSW-SLH031)。
文摘The tradeoff between sensitivity and detection range(maximum and minimum stretchability)is a key limitation in strain sensors;to resolve this,we develop an efficient and novel strategy herein to fabricate a highly sensitive and stretchable strain sensor inspired by the membrane-shell structure of poultry eggs.The developed sensor comprises a soft and stretchable surface-grafting polypyrrole(s-PPy)film(acting as the membrane)and a brittle Au film(acting as the shell),wherein both films complement each other at the electrical and mechanical levels.Au forms cracks under strain contributing to its high sensitivity and low detection limit,and s-PPy can bridge Au cracks and increase stretchability which has not been used in strain sensors before.The surface-grafting strategy not only enhances interface adhesion but also tunes the brittle property of native PPy to render it stretchable.Utilizing the synergetic effect of the membrane-shell complementary structure,the strain sensors achieve ultrahigh sensitivity(>10^(7)),large stretchability(100%),and an ultralow detection limit(0.1%),demonstrating significant progress in the field of strain sensors.The membrane-shell(Au/s-PPy)-structured strain sensor can successfully detect finger motion,wrist rotation,airflow fluctuation,and voice vibration;these movements produce strain in the range of subtle to marked deformations.Results evidence the ultrahigh performance and bright application prospects of the developed strain sensors.
