13th International Conference on Fracture June 16–21, 2013, Beijing, China -7- 3. Results In the case of rigid Polyvinyl Chloride polymer and Douglas fir the Figure 5 highlights a comparison between the experimental and analytical deformations after adjustment procedure. Déplacement brut Déplacement optimisé Experimental data Analytical data F = 1515 N x1 x2 Mode 1 Experimental data Analytical data PVC Douglas fir Figure 5. Results of the adjustment procedure As is shown in Figure 5, the adjustment procedure allows obtaining an optimized displacement fields without experimental noises. Moreover, the adjustment procedure allows estimating the rigid body motion and the crack tip orientation. These parameters are essential to adjust the experimental conditions in order to obtain the specific mixed mode boundary conditions definite by the analytical expressions of displacement fields corresponding to mixed mode loading. Note that the representation of displacements fields shown in Figure 5 take into account these parameters. According to Equations (4), the ( ) Ke a values are calculated from optimized displacement fields using the values of 1 1A , 1 2A and k values. Then the Stress Intensity Factor can be evaluated from a FE analysis via the integral invariant Mq. According to Equation (15), the energy release rate can be predicted by combining a kinematic approach (given by experimental testing) with a static approach (using numerical modeling) through determining CRDF and real SIF, respectively. The results of these energy release rate predictions are provided in Table 1 for isotropic case and Table 2 for orthotropic case. Not only does this method allow deducing the energy release rate, but moreover the use of the Mq-integral allows separating this energy for each part of both the opening and shear modes.
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