Evaluation of Mixed-mode Integral Invariant for Polymer Material Trough The Couple Experimental-Numerical Process

Abstract

Abstract. Usually the element of real structures is subject of the mixed mode loadings. This fact can be explained by the elements geometry and the loading orientations. In this case the propagation of the eventual cracks is characterised by the mixed mode kinematics. In order to characterize the fracture process in mixed mode it's necessary to separate the fracture process in order to evaluate the influence of each mode. Our study is limited to plane configurations. The mixed mode is considered as an association of opening and shear modes. The mixed mode fracture is evaluated trough the experimental tests using the SEN specimen for different mixed mode ratios. The fracture process separation is operated by the invariant integral Mθ. Moreover, our study regroups an experimental and a numerical approaches. Invariant integral. Mθ θ θ θ integralThe real structures are subject to complex loadings and the fracture process, which is characterised by mixed mode kinematics. In this case, in order to characterise the influence of the fracture mode on the crack propagation kinematics it is necessary to separate each fracture modes. In our study, the analyse is to plane configurations and the body is loaded in opening and in shear mode.According to a finite element approach, the mixed mode fracture separation is usually obtained by using an invariant integral Mθ [1,2]. Mθ integral involves the use of virtual displacement fields (ν i ) and virtual stress tensors (σ ij (ν) ) in accordance with the virtual work principle [3,4]. For plane configurations, the Mθ form is recalled in the next equation in which Ω designates the surface domain ( Figure 1):

Characterization of Wood Fracture Using Optical Full Field Methods

“…Moreover, taking into account the wood material anatomy, the fracture process is most often subject of mixed mode crack kinematics. An understanding of the crack growth under mixed-mode conditions is also an important topic when analyzing timber structural integrity [6,7,8].…”