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The plate impact experiments have been conducted to investigate the dynamic behavior of alumina. Based on the experimental observations, the three-dimensional finite element models of flyer and alumina target are established by adopting ANSYS/LS-DYNA, several cases were performed to investigate the fracture behavior of alumina target under impact loading. By analyzing the fracture mechanism and damage process of the alumina target, it is concluded that the nucleation and growth of great number of radial and axial cracks and circumferential cracks play a dominant role in the fracture behavior of alumina target. The stress histories of alumina target are simulated. By the comparison of experimental results with the numerical predictions, a good correlation is obtained.

Fracture research of natural gas pipelines with cracks is an important part of pipeline integrity evaluation. Based on the cohesive zone model (CZM), a numerical analysis is conducted of the dynamic fracture of X80 steel pipelines under explosion load. The factors considered include the crack propagation length, crack propagation velocity, dynamic crack tip opening angle (CTOA) and gas pressure. The results show that the whole cracking process can be divided into three stages: rapid cracking, stable propagation, and deceleration and stop cracking. When in the rapid cracking stage, the axial cracking of the pipeline is dominant. However, in the stable propagation stage, lateral expansion plays a more significant role. Besides, there exist upper limits on the length and velocity of crack propagation. In addition, it is also found that the time for the inflection point of rapid cracking and stable propagation is later than that to reach the velocity peak. The dynamic CTOA decreases with axial crack propagation, and the steady-state value of the CTOA is positively correlated with the load. The high-pressure gas escapes from the pipeline along the crack, resulting in the increase of air pressure outside the pipeline. Moreover, the peak pressure outside the pipeline is approximately linear its the initial crack length. The present research on the dynamic fracture mechanics behavior of the pipeline provides a necessary supplement for the test.

We study the dynamic fracture of thin-walled structure mainly due to impact and explosive loading. Therefore, we make use of a meshless smoothed particle hydrodynamics (SPH) shell formulation based on Mindlin–Reissner's theory. The formulation is an extension of the continuum-corrected and stabilized SPH method, so that thin structure can be modeled using only one particle characterizing mean position of shell surface. Fracture is based on separation of particles. We study tearing of pre-notched plates, fracture due to impact loading and dynamic fracture of cylindrical shells.

Rock burst is a multiscale dynamic fracturing process induced by unloading. To further investigate the dynamic fracturing mechanism of rock burst, a grain-based discretized virtual internal bond (GB-DVIB) method is developed. The Voronoi diagram is used to discretize the background discretized virtual internal bond (DVIB) mesh to generate the micro-structure of rock. The bond cell within a Voronoi diagram is termed as the grain cell, characterized by the linear Stillinger–Weber potential. While the bond cell cut by the Voronoi polygon edge is termed as the interface cell, in which both the tension and the shear failure are considered. The simulation results suggest that this method can reflect the contact and friction between grains and reproduce the confining pressure-dependency of compressive strength of rock. With this method, the unloading effects of the in situ stress, the grain size and the heterogeneity on rock failure are studied. The simulated results show that more tensile cracks and less shear cracks are generated when unloading a higher confining stress. When the axial stress is fixed, the total created crack area is almost a constant. The tensile crack area is basically a constant while the shear crack area increases under the condition of a higher axial stress. With decreasing the grain size, more cracks are generated, but the area ratio of the shear to the tensile cracks is almost a constant. It is suggested that GB-DVIB is an effective method for the rock burst simulation. The findings provide deep insight into the rock burst from the standpoint of dynamic fracture.

In this work, a multiscale cohesive zone model (MCZM) is developed to simulate the high-speed penetration induced dynamic fracture process such as fragmentation in crystalline solids. This model describes bulk material as a local quasi-continuum medium which follows the Cauchy–Born rule while cohesive zone element is governed by an interface depletion potential, such that the cohesive zone constitutive descriptions are genetically consistent with that of bulk element. This multiscale method proved to be effective in describing material inhomogeneities and it is constructed and implemented in a cohesive finite element Galerkin weak formulation. Numerical simulations of high-speed penetration with different shape of penetrators, i.e., square, circle and parabola nose penetrators are performed. Results show that the proposed MCZM can successfully capture spall fracture, the penetration process and different characteristics of fragmentation under different shape of penetrators.

The numerical solution of the elastodynamic problem with kinematic boundary conditions is considered using mixed finite elements for the space discretization and a staggered leap-frog scheme for the discretization in time. The stability of the numerical scheme is shown under the usual CFL condition. Using the general form of Robin-type boundary conditions some cases of debonding and the resulting acoustic emission are studied. The methodology presented finds applications to geophysics such as in seismic waves simulation with dynamic rupture and energy release. In this paper, we focus on problems of fracture occurring at the interface of composite materials. Our goal is to study both the mechanism of crack initiation and propagation, as well as the acoustic emission of the released structure-borne energy which may be used in structural health monitoring and prognosis applications.

The plate impact experiments have been conducted to investigate the dynamic behavior of alumina. Based on the experimental observations, the three-dimensional finite element models of flyer and alumina target are established by adopting ANSYS/LS-DYNA, several cases were performed to investigate the fracture behavior of alumina target under impact loading. By analyzing the fracture mechanism and damage process of the alumina target, it is concluded that the nucleation and growth of great number of radial and axial cracks and circumferential cracks play a dominant role in the fracture behavior of alumina target. The stress histories of alumina target are simulated. By the comparison of experimental results with the numerical predictions, a good correlation is obtained.