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Owing to the vast developments in computer science and technologies, recent years have seen a renewal of interest in the computational modelling of material failure in meso-macro scale. The multi-scale capability of the method is recognized as a promising tool in attacking formidable problems in fracture mechanics for heterogeneous media, such as rock, concrete or ceramic, and, indeed, has been successfully applied to the various engineering problems for industrial materials. These models have established themselves as a powerful and realistic alternative to the non-local continuum models for softening damage and fracturing. However, the quantitative macro response (such as stress–strain) from most of the current meso-mechanical models is not close enough to the behaviour of real materials. One reason for this shortcoming is that most of these models are two-dimensional. In this paper, a three-dimensional material failure process analysis model, MFPA D, is proposed. The failure behaviour of brittle materials can be simulated by this three-dimensional model. The model can realistically simulate the inelastic triaxial behaviour, strength limits, and post-peak response for both tension and compression. The capabilities of the MFPA D model to generate a wide range of damage morphologies are examined in this paper.

Cracking of reinforced concrete structures reduces stiffness and a subsequent deterioration in the capacity of structural elements. This study has investigated the use of a central difference approximation to obtain curvature mode shapes for structural elements based on the measured natural frequency and modal displacements for each load step. The findings of numerical analysis, conducted using finite element software, has been compared with experimental results. This paper also presents a proposed method of damage detection for structural elements based on an estimate of stiffness degradation using nonprismatic beam element called the Modified Flexure Damage Index (MFDI). This approach estimates damage in terms of the change in the fundamental frequency of the structural elements. It has been demonstrated that the MFDI and static strength approach provide a realistic estimate of crack damage on nonprismatic reinforced concrete beams.

The deformation mechanism of rock under different constant confining pressure was briefly analysed based on continuum damage mechanics and the effects of confining pressure on deformation, strength and macroscopic fracture patterns of model rock specimens are also studied using the Rock Failure Process Analysis (RFPA D) code. The theoretical analysis and numerically obtained results duplicate the deformation, strength (such as Young’s modulus, compressive strength, etc.) and macroscopic fracture patterns observed in laboratory. The theoretical studies and numerical simulations are extremely instructive and indicative for investigating some catastrophic hazard phenomena such as rock bursts and instability induced by excavation.

Based on the heterogeneous characteristics of rock and concrete at mesoscopic level, a 2-D mesoscopic thermo-mechanical-damage ( model) coupling model, implemented in RFPA D, is proposed by introducing elastic damage mechanics and thermal-elastic theory. The TMD model is used to study the thermal induced cracking process, including crack formation, extension and coalescence in heterogeneous materials subjected to mechanical and thermal loading. The numerical results compare well with the corresponding mathematic resolution and experimental results, which prove that the proposed model as well as the numerical system (RFPA D) is reasonable and effective in investigating the failure of heterogeneous materials subjected to thermomechanical action.

Self-Organization in rock failure progress is simulated by introducing a new numerical approach, rock failure progress analysis (RPPA D). Through the analysis of acoustic emission (AE) event time series and the frequency distribution of damage group size by correlation function and rescaled range (R/S) analysis method, it is found that the frequency distribution of damage group size complies with a power law (fractal geometry configuration) and the time series of AE event exhibits the similar scale-invariant properties and temporal long-range correlation. These fractal geometry configuration properties and long-range correlations are two fingerprints of self-organized criticality, which denonstrates the occurrence of SOC.

This paper presents a numerical simulation of double-arch tunnel excavation process by means of elasto-plastic finite element method. To perform a fully 3D numerical analysis of the whole excavating and supporting process, a FEM model including the surrounding rock and supporting structure was developed, and the whole process is divided into 20 construction steps according to the actual construction sequence. The results were satisfactory and were reasonably close to the displacement data monitored in the construction field. In the second part of the article, the redistribution of stress in shotcrete, lining and anchor against each excavation step was studied to understand the interaction between rock and the supporting structure. Furthermore, the load pattern in surrounding rock and the supporting structure were studied to analyze the influence of excavation in adjacent tunnel and find out the reasonable distance between adjacent excavation surfaces. The results obtained provide a better understanding of excavation process of double-arch tunnel, and is helpful for guiding design and construction.

In the present study, layered foam cladding is proposed to enhance the energy absorption capacity against blast load. The energy absorption of the layered foam cladding is investigated based on a rigid, perfectly plastic, locking foam model. The maximum blast impulses that can be resisted by different configurations of layered foam cladding are calculated. It is shown that a double-layer foam cladding can resist much higher impulse and is flexible for application of different purposes.

Numerical analysis is an important tool in obtaining a detailed understanding about explosive phenomena. In this research, we perform the analysis of multilayer model with the air layer. In our calculation code, the analysis of compressible substances, which cells transform greatly (like air) generally is very difficult. In this research, we used LS-DYNA3D, an analysis code using a finite-element method. By analyzing the stress state of the air hole circumference, multilayer models such as air, water and structure are analyzed and it aims to get the propagation process of the shock wave. The multi-material Arbitrary Lagrangian Eulerian (MMALE) [1] method improves upon pure Eulerian formulation by allowing the reference fluid meshes to translate, rotate and deform, thus minimize the amount of flux transport, and reduce mesh size of the reference fluid meshes.

Usually, it is difficult to obtain the equation of state (EOS) for the non-ideal explosive, such as emulsion explosives (EMXs), that is most used in an industrial explosive. The reason is that the detonation performance of a non-ideal explosive changes with the charge diameter and confinement a lot. In this research, as for the EMXs, it asked for the parameters of the JWL EOS obtained from the shape of an underwater shock wave (Underwater Explosion Test). Numerical calculation was performed about the detonation phenomenon of EMXs using this equation, and it compared with the experiment. The result was well in agreement between them.

Explosive forming is one of the unconventional techniques, in which, most commonly, the water is used as the pressure transmission medium. The explosive is set at the top of the pressure vessel filled with water, and is detonated by an electric detonator. The underwater shock wave propagates through the water medium and impinges on the metal plate, which in turn, deforms. There is another pressure pulse acting on the metal plate as the secondary by product of the expansion of the gas generated by detonation of explosive. The secondary pressure pulse duration is longer and the peak pressure is lower than the primary shock pressure. However, the intensity of these pressure pulse is based also on the conditions of a pressure vessel. In order to understand the influence of the configuration of the pressure vessel on the deformation of a metal plate, numerical analysis was performed. This paper reports those results.