Coupling Analysis of Vibration and Fatigue Crack Propagation for a Breathing Cracked Beam
The coupling effect of vibration and fatigue crack propagation for a cracked cantilever beam is studied in this paper. The dynamic characteristics and fracture mechanics parameters are calculated by using 2D 8-nodes elements in FEM code. The nonlinear dynamic behavior of breathing crack is described by a frictionless contact FEM model. Linear fracture mechanics theory is used to calculate the stress intensity factor. At resonant state, coupling effect is significant between vibration and crack propagation. The response of beam under harmonic excitation is extremely sensitive to the structure natural frequency decrease which is caused by crack length growth. An approach of sweeping crack length analysis is proposed in resonant response evaluation of cracked beam. Two numerical tests are calculated to investigate coupling effects at resonant state: crack arrest problem and crack unstable propagation problem.