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The explosion in foundation poses a significant threat to people and buildings. Currently, a unified empirical prediction formula for crater in calcareous foundation has not been established. In this paper, analyzed the types and sizes of explosion crater with different scaled burial depths through field tests and numerical simulation. In field tests, revealed the influence of scaled burial depth on the type and size of explosion crater and obtained the critical scaled burial depth for three different types of explosion craters, namely ejecta-type crater, collapse-type crater and covert explosion. Through the Smooth Particle Hydrodynamic-Finite Element Method (SPH-FEM) coupling algorithm, studied the movement trajectory of sand particles around the explosive at the moment of explosion in detail. Based on the field tests and numerical simulation results, it was found that calcareous sand has a smaller specific gravity due to its own characteristics, and the size of the explosion crater is larger than that of quartz sand at the same scaled burial depth. Obtained an empirical formula for crater in calcareous sand. Which can quickly predict the size of explosion crater and provide calculation basis for explosion resistant design in calcareous sand foundations. [ABSTRACT FROM AUTHOR]

Experimental and analytical researches have shown that the use of the bottom air-deck blasting improves fragmentation and reduces toe problems. In this research modelling of bottom air-deck blasting in a single hole, using numerical methods was taken into account. Considering the advantages of the Smoothed Particle Hydrodynamics (SPH) method, this method was used for modelling. In order to reduce the runtime of the process, the SPH–FEM coupled method was applied, using LS-DYNA software. To validate the modelling, the results of an experimental modelling of a single blast hole, in Barre granite was used. The results have shown that at the start of detonation, as the first free face is the bottom air-deck, hence, the blasting shock wave and explosive products move toward the air-deck area at a speed of 2.5 km/s and pressure on the wall of the blast hole in the air-deck area is more than the one at the starting point of detonation. Also, in conventional blasting, initial induced pressures are more than ones induced by air-deck blasting, but regarding the high attenuation of waves in conventional blasting, the applying time of pressures is very small. In bottom air-deck blasting, although the level of initial pressures are low, however, multiple impacts of blast waves in the air-deck area can transform compressive stress to tensile stress and produce higher and longer duration waves. These phenomena can contribute to an increase in the creation of fractures and improve the fragmentation at the bottom of the blast hole. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Disasters is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper explores the feasibility of using the coupled smooth particle hydrodynamics–finite element method (SPH–FEM) to study the gear rack and meshing impact problem. Firstly, a numerical model containing both SPH and FEM units is established, and its accuracy is verified. Then, the principle of gear rack meshing impact is analyzed from the perspective of impact dynamics theory, and the formula of maximum meshing impact force is derived. Finally, the meshing impact process of the rack and pinion is simulated using the coupled SPH–FEM method, and experiments are designed to verify it. The analysis results show that the SPH–FEM coupling method can simulate the meshing impact behavior of the gear mechanism more accurately. On the other hand, the severity of the impact in each operating section was obtained. It is also found that the impact stress has reached the material's tensile limit, revealing the mechanism of tooth surface wear caused by the impact. The results of the study provide a choice of research methods for gear mechanism meshing impact and also provide some reference for gear rack tooth shape optimization. [ABSTRACT FROM AUTHOR]

The titanium/aluminum composite materials overcome the limitations of single metal materials and achieve lightweight, high-strength, and corrosion-resistant properties. However, there have been no reports on explosion-welded composites of titanium alloys and seven-series aluminum alloys. Therefore, TA1/Al1060/Al7075 explosion-welded plates with three different explosive thicknesses were successfully prepared using Al1060 as the transition layer. The SPH-FEM coupled algorithm was employed to analyze the detonation process in detail and predict the interface under different explosive thicknesses. The results showed that during the explosion welding process, the high temperature, pressure, and high-speed impact resulted in significant plastic deformation and jetting phenomena at the bonding interface, which were in good agreement with the experimental observations. With the increase in explosive thickness, the TA1/Al1060 bonding interface exhibited a flat shape, while the Al1060/Al7075 interface transitioned from a flat to a wavy morphology. Moreover, the crack, vortex, and TiAl3 were observed at the interface. Mechanical testing results revealed that the composite plate with a 35 mm explosive thickness exhibited the best tensile, shear, and bending performance, indicating the optimal process parameter. This study provides significant support and reference for the application of explosion welding technology in titanium alloys and seven-series aluminum alloy composite materials. [ABSTRACT FROM AUTHOR]

In this study, experimental and numerical investigations have been done to explore the effect of the particle properties on the erosion behavior of aluminum alloy during the abrasive air jet machining (AAJM) process by using the novel medium-hard amino thermoset plastic (ATP) and conventional super-hard alumina (Al2O3) particles. In the numerical simulation, a novel linear elastic material model with the failure standard was proposed to define the ATP particle and the conventional rigid material model was used to define the Al2O3 particle. Meantime, the smooth particle hydrodynamics (SPH) interpolant with the moving-least-squares method was used to establish the impact target model. Then, a multi-particle impact model based on the SPH and finite element coupling method (SPH-FEM) was further developed to investigate the particle impact process. It indicates that the SPH-FEM method can be used to simulate the erosion behaviors of the aluminum alloy during the AAJM process by using not only the super-hard Al2O3 particle but also the medium-hard ATP particle, and the simulation results are fundamentally consistent with the experimental ones. The results demonstrate that the effect of particle hardness on erosion behavior is much greater than that of compressive air pressure. Furthermore, there exists an optimal impact angle where the surface material can be removed by chip formation resulting in the maximum material removal rate, and the surface erosion behavior can be accurately predicted by simulation. Moreover, with the particle hardness increasing, the optimal impact angle would be reduced accordingly. [ABSTRACT FROM AUTHOR]

Drilling and blasting methods have been used as a common driving technique for shallow-hole driving and blasting in rock roadways. With the advent of digital electronic detonators and the need for increased production efficiency, the traditional blasting design is no longer suitable for deep hole blasting. In this paper, a disperse charge cut blasting method was proposed to address the issues of low excavation depth and high block rate in deep hole undercut blasting. First, a blasting model was used to illustrate the mechanism of the deep hole dispersive charge cut blasting process. Then, continuous charge and dispersed charge blasting models were developed using the smooth particle hydrodynamics-finite element method (SPH-FEM). The cutting parameters were determined theoretically, and the cutting efficiency was introduced to evaluate the cutting effect. The blasting effects of the two charging models were analyzed utilizing the evolution law of rock damage, the number of rock particles thrown, and the cutting efficiency. The results show that using a dispersed charge improves the cutting efficiency by about 20% and the rock breakage for the deep hole cut blasting compared to the traditional continuous charge. In addition, important parameters such as cutting hole spacing, cutting hole depth and upper charge proportion also have a significant impact on the cutting effect. Finally, the deep hole dispersed charge cut blasting technology is combined with the digital electronic detonator through the field engineering practice. It provides a reference for the subsequent deep hole cutting blasting and the use of electronic detonators in rock roadways. [ABSTRACT FROM AUTHOR]

The objective of the present study is to propose a numerical method to simulate the collision process between a massive ice floe and a marine structure using the coupled SPH-FEM model. The elastoplastic constitutive model with a von Mises yield surface is used to simulate the ice mechanical behaviour. The effectiveness of the coupled SPH-FEM method is verified by comparing the numerical results of failure force, failure time, and fracture patterns with those of the documented experimental results of the three-point flexural strength model. Then the collision scenario of a stiffened panel subjected to a massive ice floe is addressed based on the proposed method. The impact force, wave disturbance phenomena and structural deformation of the numerical simulation show a good agreement with the documented experimental results. The coupled SPH-FEM method can improve the reliability and efficiency of the ice-structure collision simulation. This developed model can investigate the ice-structure collisions. [ABSTRACT FROM AUTHOR]

The existence of karst cavities has an important impact on the safety of foundation pit excavation projects. It is of engineering guiding value to study the influence of karst cavities on the blasting process of foundation pits and how to optimize the stiffness of cement mortar to improve the blasting effect. Based on the karst foundation pit bench blasting project of Shenzhen Dayun Foundation Pit Project, this paper adopts the SPH-FEM coupling calculation method to study the influence of karst cavities, cavity-filling water and cavity-filling silt clay on the rock-blasting process of bench blasting. We analyzed the development process of blasting damage of rock when the stiffness of karst cavity grouting filling changes under the conditions of slightly weathered, moderately weathered and strongly weathered limestone. The calculation results show that the karst cavity near the blasthole changes the direction of the minimum resistance line, which leads to the release of blasting energy; the rock breaking effect is improved when the karst cavity is filled with water medium and clay medium. Under the three limestone conditions, after the karst cavity is pretreated by cement grouting, the increase in the stiffness of the cement mortar makes the rock damage area first increase and then decrease after the karst cavity implosion, and There is a critical cement mortar stiffness that makes the best rock breaking effect. The critical cement stiffness of micro-, medium- and strongly weathered limestone is 2.2%, 6.1% and 27% of the blasted rock mass, respectively, which makes the karst cavity wall stress reach the peak value, and the rock-breaking effect is the best at this time. [ABSTRACT FROM AUTHOR]

When the drilling and blasting method is used to construct a tunnel through the karst stratum, the coupling effect of the blasting load and the karst water pressure in front of the tunnel face exposes the tunnel face to the risk of water inrush, which threatens the safety of personnel and property. It is very important for the design and construction of related tunnels to study the evolution mechanism of water inrush in karst tunnels and determine the minimum thickness of outburst prevention under blasting. Relying on the Dejiang tunnel Project in Tongren City, this paper adopts the Smoothed Particle Hydrodynamic–Finite Element Method (SPH-FEM) coupling calculation method to study the evolution process of water inrush in karst tunnels under blasting, analyzing the results of water inrush in tunnels under different rock wall thicknesses under blasting. Then, according to the regression of rock wall stress peak data, the analysis determines the minimum outburst prevention thickness of the karst tunnel. The research results show that there is a superposition effect between the blasting stress wave and the gravitational interaction of the karst water itself, and that the Smoothed Particle Hydrodynamic (SPH) particles in the aquifer cause damage and cracks to the rock wall under the coupling action of the blasting load and the karst water pressure, further leading to the expansion of the cracks and the formation of inrush channels. the stress, vibration velocity, and displacement of the unit at the junction of the aquifer and the rock layer show a trend that first decreases, then increases, and then decreases with an increase in the thickness of the rock wall. Based on the actual geological conditions of the Dejiang tunnel project parameters, when the thickness of the rock wall is 3.08 m, the peak stress of the rock formation unit at the junction with the aquifer reaches the maximum value. In order to avoid water inrush during blasting, the minimum outburst prevention thickness should be greater than 3.08 m. Based on the analysis results, a corresponding water inrush prevention plan was formulated on site which effectively guaranteed construction safety and, at the same time, verified the reliability of the analysis results. The relevant research results can provide useful references for similar projects. [ABSTRACT FROM AUTHOR]

The damage of pillars induced by blasting mining of mine room is vital to mining safety; however, the effect of blasting damage on the pillars' stability is often neglected and not clear enough. To reveal the blasting damage characteristics of pillars in deep mining, the SPH-FEM-coupled method was employed to realize the dynamic simulation based on a three-dimensional model of fan-pattern boreholes, and the blasting damage characteristics of pillars under different in situ stress and different lateral pressure coefficients were studied. The results indicate that in the central section of blast holes, the tensile stress generated by blasting load is restrained by the in situ stress, which will reduce the damage depth of pillars, but the section where the blasting damage is maximum is not always located in the blast hole center, the in situ stress will make the maximum damage section closer to the free surface, and the strength of pillars will be overestimated that is dangerous for safety production due to ignoring the blasting damage. In order to ensure the pillar stability and reduce the influence of blasting damage on pillars, the safety distance at different buried depths was suggested and the optimization of detonation sequence was proposed. The research can provide a certain reference for the stability analysis of blasting excavation in the deep mining. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, more and more researches have been carried out on the erosion mechanism of abrasive particles on target materials in the abrasive waterjet cutting process. However, the effect of material property factors on the target erosion damage is rarely studied systematically. In this work, a 3D smoothed particle hydrodynamics-finite elements model is established for the simulation. The controlled variable method is used to study how each material property factor affects the erosion process of single abrasive particle and to find out the key material property factors of Al6061-T6 and Ti-6Al-4V. The influence of the interaction of the key material property factors on the target erosion damage is further evaluated using the orthogonal test method. [ABSTRACT FROM AUTHOR]

Seismic resilience of critical infrastructure, such as liquefied natural gas (LNG) storage tanks, is essential to the safety and economic well-being of the general public. This paper studies the effect of different ground motions on large LNG storage tanks under four different site conditions. Key parameters of structural design and dynamic analysis, including von Mises stress of outer and inner tanks, tip displacement, and base shear, are analyzed to directly evaluate the safety performance of the large LNG tanks. Because the size of an LNG tank is too large to perform any experiments on a physical prototype, Smoothed Particle Hydrodynamics-Finite Element Method (SPH-FEM) simulation is used as a feasible and efficient method to predict its seismic response. First, the accuracy of the SPH-FEM method is verified by comparing sloshing frequencies obtained from theoretical formulation to experimental results and SPH-FEM models. Then, the seismic response of a real-life 160,000 m3 LNG prestressed storage tank is evaluated with different liquid depths under four site classes. Simulation results show that the tip displacements of the LNG tank at liquid levels of 25% and 50% under site class IV are nearly identical to that of 75% and 100% under site class II. In addition, the maximum von Mises stress of the inner tanks exceeds 500 MPa in all four site classes and jeopardizes the structural integrity of large LNG tanks. As a result, optimization of structural design and the establishment of an early warning system are imperative to the safety of LNG tanks at high liquid levels. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flow slide is a flow-type landslide, which has high mobility and is destructive to the downstream infrastructures and buildings. In this study, a numerical method is presented to simulate the runout process of flow slide, and the interactions between flow slide and buildings on three-dimensional terrain considering the destruction process. In this proposed method, the flow slide is simulated by smoothed particle hydrodynamics (SPH) and the buildings are simulated by the finite element method (FEM). A node-to-surface contact algorithm is adopted to transfer displacements and contact forces between the flow slide and the buildings. An element erosion algorithm is adopted to simulate the destruction process. The method is validated using an analytical solution to dam break problem and the experimental results in two flume tests. A catastrophic flow slide involving building destruction is then simulated to further test the model performance. The flow depth, flow velocity, deposition area, and building damage degree are all reasonably simulated. The typical destruction process of buildings and patterns of the flow slide are also identified. The method will contribute to a better understanding of flow-structure interactions and is a promising tool for hazard analysis and mitigation. [ABSTRACT FROM AUTHOR]

Composite laminates can potentially reduce the weight of aircrafts; however, they are subjected to bird strike hazards in civil aviation. To handle their nonlinear dynamic behaviour, in this study, the impact damage of composite laminates were numerically evaluated and designed by means of smoothed particle hydrodynamics (SPH) and the finite element method (FEM) to simulate the interaction between bird projectiles and the laminates. Attention was mainly focused on the different damage modes in various laminates' plies induced by bird impact on a square laminated plate. A continuum damage mechanics approach was exploited to simulate damage initiation and evolution in composite laminates. Damage maps were computed with respect to different ply angles, i.e., 0°, 45° and −45°. The damage distributions were comparatively investigated, and then the ply design was considered for crashworthiness improvement. The results aim to serve as a design guideline for future prototype-scale bird strike studies of complex laminated structures. [ABSTRACT FROM AUTHOR]