Fatigue life prediction of cfrp composites in plane bending by modal analysis

Abstract

This is investigation of the fatigue behaviour of carbon fiber reinforced polymer laminates under various angles of deflections of cantilever beam in bidirectional (R=-1) plane bending. The Unidirectional 45˚ carbon fiber oriented CFRP composite were tested at different cantilever bending angles at frequency of 8 Hz. The non- destructive modal testing is conducted to evaluate reduction in structural stiffness in fully reversed plane bending in terms of natural frequency. The modal test at specific intervals is conducted by interrupting the fatigue test. The curve fitting technique for prediction of fatigue life over experimental analysis is used to formulate behaviour of CFRP in plane bending fatigue. It is shown that A Non-destructive Testing method (Modal Test) can be applied for the fatigue life estimation of CFRP laminates. The natural frequency reduction model is able to represent the overall reduction in stiffness due to fully reversed plane bending fatigue.