Experimental Study on Damage Identification of Pipeline Based on Operational Strain Modal Shape

In order to make damage detection, real-time safety evaluation and life prediction of pipelines, and hence prevent pipeline accidents, difference formulas of strain mode for damaged pipelines are derived based on vibration tests and the character of one-dimensional continuum of pipelines, and a mathematical model of direct indexes for damage location and degree identification was built. Then, physical model tests for three pipelines in different damage status are carried out to identify their damage. The results show that when using the natural frequency as an identifying global indicator for damage identification, the maximal change rate of pipeline natural frequency is only 6.71% and the damage cannot be identified effectively due to the limitation of less information; the difference value of strain sensitivity, however, has more obvious mutations in damage area and can identify the pipeline damage correctly.