Bridged crack - opening outside of the bridged zone and stresses at the material interface

Для прямолинейной трещины со связями в концевой области на границе соединения материалов получены выражения для расчета раскрытия трещины вне зоны, занятой связями, и напряжений за вершиной трещины. Рассматривается действие однородных - нормальной и сдвиговой - внешних нагрузок. Размер концевой области трещины не полагается малым по сравнению с длиной трещины. Выполнено сопоставление с результатами, полученными методом граничных элементов. For a straight interfacial crack with bridged zone the expressions for calculating the opening of the crack outside of the bridged zone and stresses ahead of the crack tip are obtained. The action of uniform normal and shear external loads is considered. The size of the crack bridged zone is not considered small compared with the length of the whole crack. A comparison with the results obtained by the boundary element method is presented.

Experimental and numerical investigation of mode II failure behavior evaluation using three point bend, end notched flexure test

In the present paper the primary task is the study involving calculation of elastic properties of the composite from the individual properties of the E-glass fiber (650 GSM) and the properties of resin LY 556 with Hardener HY951. The properties of varying volumetric ratio of fiber are obtained from calculation of the properties by using rule of mixtures. Experimentally validating the theoretical and numerical approaches by comparing the load-displacement response and crack paths observed in large scale bridged crack propagation in laminated fiber-reinforced composites specimens. An effort is being made to develop a numerical framework for cohesive crack propagation and demonstrating its effectiveness by simulating failure through crack propagation in materials with complex microstructure like fiber reinforced composites. Experimentally validating the theoretical and numerical approaches by comparing the load-displacement response and crack paths observed in large scale bridged crack propagation in laminated fiber-reinforced composites specimens.

Brittle fracture in a periodic structure with internal potential energy. Spontaneous crack propagation

Spontaneous brittle fracture is studied based on the model of a body, recently introduced by two of the authors, where only the prospective crack path is specified as a discrete set of alternating initially stretched and compressed bonds. In such a structure, a bridged crack destroying initially stretched bonds may propagate under a certain level of the internal energy without external sources. The general analytical solution with the crack speed–energy relation is presented in terms of the crack-related dynamic Green's function. For anisotropic chains and lattices considered earlier in quasi-statics, the dynamic problems are examined and discussed in detail. The crack speed is found to grow unboundedly as the energy approaches its upper limit. The steady-state sub- and supersonic regimes found analytically are confirmed by numerical simulations. In addition, irregular growth, clustering and crack speed oscillation modes are detected at a lower bound of the internal energy. It is observed, in numerical simulations, that the spontaneous fracture can occur in the form of a pure bridged, partially bridged or fully open crack depending on the internal energy level.