Predicting the fatigue cycles on aluminum panels

A finite element method was developed and used to predict fatigue crack gro wth in thin, middle-cracked panels. Fatigue cycles were calculated from pre dicted fracture toughness, a predicted R-curve point, and the dissipated pl astic energy under a fatigue load. Experimental fracture and fatigue parame ters were not required. The method worked best when crack closure did not o ccur. A plot of the dissipated plastic energy Versus crack growth showed wh ich fatigue cases had partial closure and which would provide good results. Smooth fatigue energy curves resulted in predicted fatigue cycles within 1 0% of the number of experimental cycles. (C) 2001 Elsevier Science Ltd. All rights reserved.