COMPUTER SIMULATION OF COMBINED SPLITTING FORCE: STRAIN LOADING OF DOUBLE-BEAM SAMPLES

The purpose of this work is to study possible schemes of loading double-cantilever beam (DCB) specimens to replenish the arsenal of the methods used in their testing. Mathematical analysis of ten different modes of specimen loading is carried out for different methods of immobilizing and loading of the cantilever including splitting force, deformational and combined loading. Analytical expressions for the stress intensity factor (SIF), as well as the dependence of the beam spread angle θ (rotation angle of the beam head) on the crack length are derived. Those dependences form a basis for developing the methods for measuring the dynamics of the crack length changes during testing. The energy approach is used in determination of the stress intensity factors. The classical scheme of force loading of the DCB specimen by a pair of forces is supplemented with a loading scheme with two pairs of forces applied to different cross sections. A modification of the DCB specimen by rigid binding of the ends of its consoles when each shoulder of the specimen is considered a singly statically indeterminable beam and DCB specimen becomes a double-beam specimen is also considered. The possibility of rearranging the sections of the load application and position of the rigid support-link is also studied. The deformational loading is simulated by inserting a wedge in one or two sites along the specimen length. The wedge effect is modeled by a preset deformation in one of the sections and binding of the specimen consoles in the other. Formulas of the stress intensity factor for the DCB specimen asymmetric with respect to the crack propagation line upon pure force loading by the forces applied in one section are presented. References to the reports on experimental implementation of a number of proposed and considered load configurations are presented.

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