Analysis of the influence of fatigue on the bending of Peltogyne sp.

Abstract

This work presents the fatigue analysis on Peltogyne sp.. The specimens were submitted to three-point bending tests during 300,000 cycles. Analysis of influence of the number of cycles on wood bending stiffness was performed by comparing MOE (longitudinal modulus of elasticity) measured every 100,000 cycles applied. At the end of the application of 300,000 cycles, a decrease in the MOE value of three specimens was observed in relation to the MOE measured at the beginning, without application of cycles. A fourth specimen showed an increase in the MOE value. The visual analysis of the specimens during the tests is also important since they showed cracks. Microscopic images were performed to support the analysis of the observed behavior. With the application of time and more stresses on the piece, the crack can increase to the point of generating rupture and collapse of the structure, so the cracks were a determining factor to confirm the suspicions regarding the weakening of the wood due to fatigue of the material.