On the mode I and II failure of three Cameroonian hardwoods with orthotropy rate evaluation

Abstract

This work uses the M-theta method on a new proposed specimen called "I-specimen" for the numerical modeling of cracks on some tropical hardwoods in general and in particular on some Cameroonian woods. The finite element analysis of fracture in an orthotropic medium is developed. The fracture algorithm is introduced in a finite element software Cast3M and, with an incremental orthotropic formulation, the simulation of crack growth is computed. Using this method, stress intensity factors and energy release rate are calculated for Mode I and II failures. The energy release rate and stress intensity factors are numerically deduced using “I-specimen” to characterize three Cameroonian hardwoods under mode I and II loading for different crack growths. The specimen used has better characteristics than other samples generally used in the literature and its geometry is very simple to define. The proposal of a new geometry that can guarantee the reproduction of the different failure modes while exhibiting some stability of the crack parameters G and K during propagation was evaluated and compared to other specimens given by the fracture mechanics literature. For each fracture mode, the influence of the orthotropy rate parameters on the energy release rate was investigated.