Structural vibrational analysis of civil pipelines for fault detection

The drinkable fresh water is a valuable resource that exists in nature that is required to be carefully preserved. The fresh water is essential for the life of human being and there is a great amount of loss of this valuable resource in everyday activities due to various reasons. One of the major reasons of loss of drinkable water is due to the leakage during its distribution throughout the water distribution network. Hence, if the leakage of water can be prevented it can have considerable merit in saving drinkable water resources. In this study, the problem of leakage in water distribution network has been analyzed by vibrational responses of the structure of the pipe. The problem of leakage has been investigated in two stages. First, when there is leakage in the pipeline and the purpose is to find the position of the leak and stop it. Second, when there are damages on the pipe that are able to end to leaks. Finding such damages is useful for prevention of leakage in civil pipelines. The vibrational responses of the structure of the pipe have been obtained by different methods such as impulse excitation, sweep excitation, without any excitation (steady-state response), and through the application of a designed input signal and measuring the responses. The designed signal is called intelligent signal since it not only has the aim to detect the presence of damages on the pipe but also has the aim to communicate this information throughout the pipe network. This study is more focused on damage detection by the application of the intelligent signal. According to the analyses that have been done on the responses, some techniques have been proposed for the identification of leakage and damage on civil pipelines. For leakage, root mean square (RMS) analysis of the time history is useful for detection of leaks. For damages on the pipe, the shift in the first natural frequency of the pipe and change in the amplitude level of the vibrational responses of the intelligent signal as an input to the structure is useful for detection of the damage on the pipe.