Table of Content

08 December 2023, Volume 44 Issue S1

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Electronic edition of this issue

2023, 44(S1):  0. 

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Contents

Contents

2023, 44(S1):  0. 

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Overview of Fragmentation Power Field of Warhead under Dynamic Explosion

JIANG Jinzuo, XU Xiangyun, REN Wangjun, YU Xiao, YAO Meili

2023, 44(S1):  1-8.  doi:10.12382/bgxb.2023.0715

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For a long time, the dynamic explosive fragment field of warhead has been paid attention to by researchers. The velocity, mass and density of fragment under the action of dynamic explosion have been studied, especially the correlation and the difference between static explosion and dynamic explosion of warhead are one of the hot topics. In order to further discuss the research progress of dynamic fragmentationpower field of blast-fragmentationwarhead, the main factors affecting the velocity field, mass distribution field, and flying direction and density of fragments are expounded by summarizing the research focus in existing relevant literatures, and the problems and difficulties in analyzing the relevant factors in existing literature are pointed out. Among them, the influence of the warhead's own motion condition on the fragmentation power field distribution is analyzed, and the difficulties in the current research in this field are discussed.And then the suggestions for further research work are put forward: develop and perfect the dynamic explosion test technology; perfect the warhead dynamic explosion fragmentation power field theoretical model; and optimize the numerical simulation technology of warhead dynamic explosion process.

Experiment and Numerical Simulation of Explosion Resistance Performance of Main Girder of Self-anchored Suspension Bridge Coated with Polyurea

ZHOU Guangpan, WANG Rong, WANG Mingyang, DING Jianguo, ZHANG Guokai

2023, 44(S1):  9-25.  doi:10.12382/bgxb.2023.0863

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The anti-explosion protection effect of the girder of self-anchored suspension bridge coated with polyurea under explosion loads is studied by taking Hunan Road Bridge in Shandong Province as the background. The failure characteristics and dynamic response of the girder of self-anchored suspension bridge under explosion loads are studied through a combination of experiments and numerical simulations. Two sets of 3kg TNT grains and one set of 5kg TNT grain are used to conduct two single explosion tests and one repeated explosion test on segmental box girder specimens made at a 1∶3 scale. The specimens are numbered as G (uncoated-polyurea box girder), PCG (coated-polyurea girder with first detonation), and PCGR (coated-polyurea girder with second detonation), respectively. The polyurea thickness at the top surface of the specimen is 1.5mm. The explosion response of specimen were numerically simulated and verified using LS-DYNA software. The results indicate that the polyurea coating can effectively enhance the anti-explosion performance of concrete girder. When the first explosion of 3kg TNT occurred at 0.4m above the middle box chamber, a penetrating elliptical hole was formed on the top plate of the middle box chamber of specimen G. The top plate of the middle chamber of PCG was not penetrated, and only a slight local dent on it occurred. After the secondary detonation of 5kg TNT, a nearly circular penetrating hole appeared on the top plate of the middle chamber of PCGR, the cracks appeared at the supports in the chambers no. 1 and no. 3. After coating with polyurea, the anti-explosion performance of the girder of the self-anchored suspension bridge has been improved by at least 20%. Under the actions of TNT equivalents of 300kg, 500kg, 800kg, and 1000kg, the penetrating holes appear in the top plate concrete of the girder without polyurea. After coating with polyurea, only slight penetration occurs when the TNT equivalent is 1000kg.

Attenuation Characteristics and Mechanism of Explosion Shock Wave Generated by Thermobaric Explosive in L-shaped and Gallery Tunnels

JI Yuguo, ZHANG Guokai, LI Gan, DENG Shuxin, XU Tianhan, YAO Jian, LI Jie, WANG Mingyang, HE Yong

2023, 44(S1):  26-40.  doi:10.12382/bgxb.2023.0745

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The explosion tests of thermobaric explosive (TBX) in L-shaped and gallery tunnels were carried out on a self-established large-scale tunnel platform. According to the shock wave overpressure, positive pressure duration and specific impulse acquired from the tests, the propagation laws of shock wave in the two kinds of tunnel are studied, and the influence of tunnel shape on the waveform evolution and attenuation ability, and the forming mechanism of attenuation difference to the shock wave are analyzed. The results indicate that, in the L-shaped and gallery tunnels, the shock wave generates multiple interactions with wall surfaces to form the multi-waveforms with multi-peaks after entering the main tunnel through branch tunnels. The specific impulse in L-shaped tunnel is not significantly different from that in long straight tunnel, and the reduction coefficients of the overpressure of air explosion at and in tunnel entrance are 1 and 1.2, respectively. Compared to the long straight tunnel, the gallery tunnel has a significant attenuation effect on the shock wave, and the coefficients of overpressure and specific impulse at turning are both about 0.6. The difference in shock wave attenuation effect between L-shaped and gallery tunnels comes from the difference in propagation paths of shock waves after reaching the connected positions of the main and branch tunnels.

Research on Thermal Safety of Warhead Charge Based on Cook-off Experimental and Numerical Simulation

KOU Yongfeng, YANG Kun, ZHANG Bin, XIAO Yiwen, LU Jianying, CHEN Lang

2023, 44(S1):  41-49.  doi:10.12382/bgxb.2023.0917

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In order to study the thermal safety of the warhead charge, a method is proposed for calculating and analyzing the thermal safety of warhead charge and determining the parameters of the reaction modelbased on the temperature of explosive cook-off, the speed of driving piston and the reaction pressureof cook-off. Taking RDX/Al/Binder explosives as an example, the thermal reaction temperature of charge before ignition and the moving speed of piston and the combustion pressure after ignition are measured using the cook-off experiments designed of multi-point temperature measurement and the speed and combustion pressure of driving piston measurement. The thermal decomposition reaction kinetics and combustion reaction model parameters of explosives are calibrated for the quantitative description of the reaction severity through numerical simulation calculation. The cracking of warhead shell is calculated by using the grid node separation calculation method, and the whole cook-off process of warhead charge is numerically simulated. The results show that, for the warhead RDX/Al/Binder explosive charge, the slower the heating rate is, the longer the charge ignition time is, the closer the ignition area is to the center of charge, the more serious the shell rupture is, the greater the kinetic energy of shell is, the greater the kinetic energy of charge is, and the stronger the charge reaction is.

Experimental Study on Cumulative Damage of Shear Wall Under Multiple Internal Explosions

BAI Zhun, HU Yutao, QIAN Bingwen, YAO Hang, LI Xian, GUO Xuekang

2023, 44(S1):  50-58.  doi:10.12382/bgxb.2023.0768

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With the improvement of guidance precision and penetration capability of missile weapons, multiple internal explosions have gradually become an important form of attacking buildings. Shear wall is an important structural component in buildings, and its damage mechanism and failure mode need to be further studied under internal explosions. In order to reproduce the constraint conditions and load scenarios of shear wall, a 1/3 scaled reinforced concrete structure was used to conduct multiple internal explosion tests with different TNT charge masses. By analyzing the crack pattern, damage level and mid-span displacement of structure component, the influence of internal explosion strength and loading times on the failure mode and damage level of the shear wall is studied. The results indicated that when the internal explosive load is small, the failure mode of shear wall would change from bending to bending-shear. However, when the internal explosive load is large, the failure mode of shear wall would change from bending-shear to complete shear. Under the multiple explosive loading scenarios, the deformation resistance of shear wall with initial mild damage is larger than that of the shear wall without initial damage. On the other hand, the deformation resistance of shear wall with the initial moderate or higher-level damage is lower than that of the shear wall without initial damage. Therefore, the correlation between multiple damages should be considered in order to evaluate the cumulative damage of shear wall component.

Basic Evolution Characteristics of Oblique Penetration of Projectile against Hard Target

CHEN Baihan, SHEN Zikai, ZOU Huihui, WANG Weiguang, WANG Kehui

2023, 44(S1):  59-66.  doi:10.12382/bgxb.2023.0865

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To summarize the general patterns of force and motion models for oblique penetration of projectiles, the penetration process of projectile against hard targets is regarded as the motion in the penetration force field based on the assumption of rigid projectile and the idea of projectile-target separation. The common law of ballistic stability and state-parameter evolution of projectile,which is independent of force models’ form, is derived based on the time translation invariance of force field and the symmetry of normal penetration. Specifically, a criterion for the motion stability of projectile in the case of normal penetration and the projectile completely penetrating in hard target can be given. The numerical solution methods for the balance and stability criteria of projectile motion in the case of oblique or incomplete penetration, are also provided. All types of criteria indicate that the penetration velocity, angular velocity, and angle of attack have the important significant impacts on the evolution of penetration state, where the angle of attack has the most significant impacton the evolution of penetration state. In addition, for any moment during the penetration process, the closeness of the penetration evolution is also proven with analytical mechanics method. The derived characteristics of projectile motion can provide guidance for the design of penetration test and simulation.

Wheel-rail Interaction Mechanism and Derailment Suppression Technology for Train Collision Accidents

LIU Teng, ZHOU Xiongfei, WANG Chengquan, JING Lin

2023, 44(S1):  67-78.  doi:10.12382/bgxb.2023.0752

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With the continuous increase of operating mileage of railway, the accidents induced by train collision are difficult to avoid entirely, which will cause heavy casualties and property losses once an accident happens. A finite element model of three-marshalling train is established to reduce the risk of the train derailment in collision accident as much as possible, in which the energy absorption device at the end of train and the wheel-rail contact state are considered. The dynamic responses of the wheelset caused by the train colliding with a movable obstacle and a rigid wall are simulated, respectively. The influences of train speed and collision angle on train derailment behavior are discussed. Furthermore, a derailment suppression device, which has the functions of lateral and vertical limits, installed on the bogie is proposed. The motion attitude, displacement and roll angle of wheelset, and the wheel-rail contact force before and after the installation of the derailment suppression device are analyzed and compared. The results show that the train derails in the form of lateral movement/lift coupling after the collision;the derailment suppression device can be used to adjust the motion posture of wheelset to a certain extent after the collision accident, and also limit the lateral movement, lifting and rolling motion of wheelset. The part of the wheel-rail contact force can be borne by the derailment suppression device, which causes the wheel-rail system to quickly recover to the normal contact state. The proposed device was demonstrated to have a certain derailment suppression ability. The obtained results can provide theoretical basis and technical support for collision passive safety design.

Experimental Study on Interaction between Bubble and Concrete Composite Slab in Near-field Underwater Explosion

LI Xu, YUE Songlin, QIU Yanyu, WANG Mingyang, DENG Shuxin, LIU Niannian

2023, 44(S1):  79-89.  doi:10.12382/bgxb.2023.1074

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The response characteristics of concrete composite slab,as the basic component in hydraulic structure under the action ofnear-fieldunderwater explosion and the law of itsinfluence on bubble motion are the key scientific issues to evaluate the damage of underwater explosion to engineering structures. The dynamic process of interaction among bubbles and two types of slab members at different blast distances is studied through a series of underwater explosion tests of reinforced concrete slab and steel-concrete-steel composite slab. The results show that the maximum radius of cylindrical charge with aspect ratio of 1 is consistent with the result calculated by empirical formula. Under the same wall conditions, the pulsation period of bubble increaseswith the decrease of the blast distance, the bubble is gradually adsorbed by the wall, and the damage effect caused by the pulsation and high-speed jet is enhanced. The influence of reinforced concrete slab on the bubble pulsation process is weaker than that of steel-concrete-steel composite slab under the same working conditions. The higher the wall stiffness is, the more obvious the directivity and effect of high-speed jet are.

Analysis on Dynamic Response of Bridge Pier under Near-field Underwater Explosion Loading

ZHOU Longyun, LI Xiaojun, YAN Qiushi

2023, 44(S1):  90-98.  doi:10.12382/bgxb.2023.0717

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The dynamic response and damage mechanism of piers under underwater explosion loading are analyzed to investigate the damage to a pier caused by underwater explosion by using the arbitrary Lagrangian-Euler method. The accuracy of the finite element model is verified through an underwater explosion test, and then a finite element model of a pier under underwater explosion loading is established. Taking the residual vertical bearing capacity of the pier as the performance index, the damage evaluation method of pier under explosion loading is put forward. The influences of explosive weight and initiation point on the damage degree of pier are discussed. The investigation results indicate that the damage to the pier caused by bubble pulsation generated by a near-field underwater explosion cannot be ignored. When the outer side of pier is detonated, the TNT weight is exponentially related to the residual bearing capacity of pier. When the weight of TNT is the same, the damage caused by the explosion inside the pier is the most serious.

Mechanism of Coupling Effect of Shock Wave and Fragments on Clamped Square Plate

ZHOU Meng, LIANG Minzu, LIN Yuliang

2023, 44(S1):  99-106.  doi:10.12382/bgxb.2023.0732

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The coupling effect of shock wave and fragments on a clamped square plate is studied based on their coupling characteristics. The dispersion mechanism of prefabricated fragments propelled by explosives is investigated using a validated finite element model, and the findings are supported by experimental evidence. The deformation and failure modes of a target plate under various loads are discussed, and the damage mechanism resulting from the coupling effect of shock wave and fragment loading is elucidated. The results demonstrate that a coupling damage effect occurs in the vicinity of explosion field when the arrival interval between the two loads is less than the response time of target plate, regardless of the order in which the loads reach the plate. The primary deformation failure modes of target plate are flexural deformation and shear perforation caused by the shock wave and fragments, respectively. Moreover, theperforation of fragments under the action of shock wave is prone to cracking and hole penetration. The study also reveals that the mechanism of shock wave and fragment interaction differs from that of individual load. The strengthof target plate is reduced and its deflection is increased under the action of shock wave, leading to penetration perforation. Furthermore, the deflection induced by the shock wave delays the penetration time, extends the perforation period, and transfers more energy to the target plate. The residual deflection of target plateunder the coupling effectjs increased by 19.2% compared to the simple superposition of the shock wave and fragment loads.

Experimental Study on Bending Performance of Ultra-high Strength Reinforced Concrete Beams under Static Loading

ZHANG Congkun, ZHANG Zhonghao, WANG Wei, LI Lei, HE Xiang

2023, 44(S1):  107-116.  doi:10.12382/bgxb.2023.0751

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11 sets of reinforced concrete beams with different steel bar strength, concrete strength, and reinforcement ratios are designed and manufactured to study the bending performance of ultra-high strength reinforced concrete beam. The failure morphology, bending response, yield load, ultimate bearing capacity, and crack width of specimen are experimentally studied using a four-point static loading method. The results indicate that the maximum bearing capacity of reinforced concrete beam can be improved by strengthening the strength of steel bars, the increase in the strength of concrete has a relatively small impact on the flextural bearing capacity of beam, and the increase in the longitudinal reinforcement ratio can significantly improve the flextural bearing capacity of reinforced concrete beams. The HTRB600/700 ultra-high strength reinforced concrete beam is the same as ordinary reinforced concrete beam in terms of stress morphology, bending response, and failure mode. Its yield load and ultimate bearing capacity can still be calculated usung relevant code formulas. For bending beam components, the recommended design value for tensile strength of HTRB600 steel bars is 520MPa, and the recommended design value for tensile strength of HTRB700 steel bars is 610MPa; The measured maximum crack width of ultra-high strength reinforced concrete beam specimen under short-term load is greater than the calculated value in relevant specifications. Therefore, the adjustment coefficient k of a maximum crack width is proposed and the calculation formula is modified. After adjustment, the calculated value obtained is in good agreement with the experimentally measured value.

Influence of Spin on the Penetration Effect of Projectile

CHEN Baihan, WANG Libin, ZOU Huihui, WANG Weiguang, WANG Kehui

2023, 44(S1):  117-124.  doi:10.12382/bgxb.2023.0864

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A projectile penetration model considering spin angular velocity is developed to explain the better performance of penetrating projectile with spin angular velocity in experiment and simulation. The effect of spin angular velocity on the projectile penetration behavior is revealed through theoretical research and simulation. The attitude dynamics analysis shows that the spin angular velocity causes the non-planar motion of projectile in general penetration cases, while the spinning projectile maintains planar motion only in ideal penetration. The derivation based on the cavity expansion theory indicates that the change in the direction of shear stress on the contact surface between projectile and target is one of the reasons for the decrease of penetration resistance. Together with the attenuation of normal stress on the cavity surface caused by shear effect, it forms the mechanism for the increase in penetration depth. The derivation of rigid body kinematics shows that the precession between targets leads to a slowdown or even decrease in the angle of fall, which is an important reason for the increase of ballistic stability in the case of multi-layered target penetration. Therefore, the spin angular velocity changes the force and motion mechanism of projectile throughout penetration, leading to the increase of its penetration depth and ballistic stability.

A Simulation Method for Non-Uniformed Distribution of Granular Materials under Strong Loading

LI Yishuo, FU Yongquan, BAI Fengtao

2023, 44(S1):  125-131.  doi:10.12382/bgxb.2023.0755

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The distribution of aggregate in concrete, the distribution of ripraps in gravity caisson wharf, and the fragment distribution of high explosive projectile are all uneven and random. The distribution is usually simplified to a uniform distribution in the process of numerical simulation, which affects the accuracy of the simulated results, but it has not been qualitatively analyzed. In this paper, a method of generating a riprap model of caisson wharf is provided, and a random stone riprap caisson wharf model based on math software is established. The force characteristics and failure modes of riprap caisson wharf are analyzed. In order to explore the damage characteristics of castaway caisson pier and sand-filled caisson pier under the underwater explosion load, a comparative study of the castaway model and the sand-filled model was carried out, and the damage results of the two models under the same conditions were summarized, which provides a reference for the damage assessment of such structures. The results show that the propagation speed of shock waves in the caisson wharf is faster than that in the sand-filled caisson wharf, and the damage of the caisson wharf is more serious than that of the sand-filled caisson wharf.

An Optical Fiber Soil Pressure Sensor with Double Sensitive Surfaces

ZHOU Huijuan, YU Shangjiang, CHEN Jinyang, CHEN Xian, MENG Xiaojie

2023, 44(S1):  132-137.  doi:10.12382/bgxb.2023.0932

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The existing fiber Bragg grating (FBG) soil-pressure sensors are prone to cause the broadening or even chirping of reflection spectrum due to the uneven stress of FBG, which reduces the measurement accuracy. A soil pressure sensor with double sensitive surfaces is designed and fabricated based on a diamond metal frame and a metalized FBG. The FBG is directly welded and fixed at both ends of the diagonal of diamond metal structure. The external pressure is applied to both ends of the grating after it is amplified by the diamond metal structure, so that the FBG is always suspended and tensioned with uniform stress. Therefore, the reflection spectrum broadening and chirping caused by uneven force on the FBG are avoided. The welding process is used to avoid the problems of creep, aging and failure caused by adhesive, and the high measuring accuracy and long-term stability of the sensor are improved. The analyzed and experimental results show that the wavelength-pressure sensitivity coefficient of the FBG soil pressure sensor is 624pm/MPa and the measuring range is 3.5MPa.

Numerical Analysis of Gas Explosion Resistance of Two-way Masonry Walls Strengthened by Spraying Polyurea

LIU Jinchun, WANG Yuying, SUN Ni

2023, 44(S1):  138-143.  doi:10.12382/bgxb.2023.0733

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In order to study the anti-explosion performance of two-way masonry wall and the reinforcement performance of polyurea on wall under the action of gas explosion, the finite element dynamic analysis software LS-DYNA is used to analyzethe dynamic response andanti-explosion capability of the unreinforced masonry wall and the walls reinforced by spraying the polyurea on the front, back and double-side under uniform loads with different peak values and action time of 100ms. The results show that: the unreinforced wall collapses under the gas explosion load with the peak overpressure of 50kPa, and its peak resistance to 100ms explosion impact load is between 40kPa and 50kPa; compared with the two-way wall reinforced by spraying the polyurea on its front, the backside reinforcement method is more economical and practical. The wall strengthened on the front cracks and collapses under 50kPa load, while the displacements of the back reinforced wall and the double-sided reinforced wall are only 35.3mm and 33.6mm, respectively, and the polyurea spraying on the back can effectively prevent debris splashing.

Numerical Simulation of Temperature Rise of 4340 Steel Projectile Penetrating into 45# Steel Target

YU Shuangyang, PENG Yong

2023, 44(S1):  144-151.  doi:10.12382/bgxb.2023.0734

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In order to obtain the basic characteristics of the temperature rise of projectile during the process of penetrating into a metal target, the temperature rise of 4340 steel spherical projectile penetrating into 45# steel target isexperimentally studiedwith a first-stage light gas gun. Based on the experimental conditions, a finite element model of 4340 steel projectile penetrating into 45# steel target is established using ANSYS/LS-DYNA software. After a good fit between the numerical simulation model and the experimental results, the effects of the initial velocity of 4340 steel projectile, the thickness of target plate and the temperature distribution of two layers of target when 4340 steel projectile penetrates into 45# steel target are discussed in detail by changing the initial conditions. The results show that the temperature rise of projectile is mainly distributed in the head of projectile during the process of penetration. The temperature rise of projectile during penetration increases with the increase of velocity. When two layers of target are penetrated, the temperaturerise of projectile mainly occurs in the process of penetrating into the first layer of target.

Study on Deterioration and Damage Performance of Concrete at Different High Temperatures

ZHANG Zhonghao, WANG Wei, ZHANG Guokai, WANG Zhen, WU Gu

2023, 44(S1):  152-159.  doi:10.12382/bgxb.2023.0731

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Concrete is a commonly used building material. In order to further explore its degradation and damage performance after high-temperature cooling, the dynamic mechanical properties of C30 concrete material after cooling at different temperatures were tested through the ϕ74mm split Hopkinson pressure bar, and the stress-strain curves at different temperatures and different strain rates were obtained. The dynamic compressive strength, damage variables and crushing morphology of concrete are discussed. The results show that the dynamic compressive performance of concrete decreases limitedly in the range of 100~200℃, but its mechanical properties decreases significantly and its broken form is serious when the temperature reaches 400℃ and above. Too high temperature can cause damage to the concrete material, the high temperature cooling causes the concrete to produce a strain softening effect, and the concrete material also shows the strain rate hardening effect under high strain rate. Excessive crack propagation inhibites the growth of damage variables to a certain extent. The higher strain rate makes the concrete sample be broken more seriously after the same temperature treatment. And the excessively high temperatures would aggravate the deterioration and damage of concrete.

Propagation Law of Shock Wave jn Z-shaped Diffusion Chamber

WU Zhangjun, WANG Xueming, YU Wenjun, DENG Shuxin, CHEN Jianyu, JIN Dongyan, YU Bingbing

2023, 44(S1):  160-169.  doi:10.12382/bgxb.2023.0896

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In this paper, a three-dimensional numerical calculation model of Z-shaped diffusion chamber is established based on LS-DYNA. The wave dissipation effect of the diffusion chamber under the impact of incident shock wave with different characteristic parameters is discussed, and the influences of different feature sizes of diffusion chamber on the wave dissipation efffect are studied. The results show that the wave dissipation effect of diffusion chamber under the impact of shock wave with short duration is significantly affected, and the wave dissipation effect of diffusion chamber under the impact of shock wave with short duration is 8% higher than that with long duration. The wave dissipation effect of diffusion chamber increases with the peak intensity of incident shock wave, but the improvement in wave dissipation effect is not obvious when the peak intensity of incident shock wave is greater than 0.9MPa. The wave dissipation performance of diffusion chamber is the best when the diffusion ratio and length-to-diameter ratio are 5. The increase in the diffusion ratio of diffusion chamber has a significant influence on its wave dissipation effect. The increase in length-to-diameter ratio has no obvious effect on the wave dissipation effect of diffusion chamber.

Liquefaction Characteristics of Three-phase Saturated Calcareous Sand under Explosive Loading

LI Xiaodong, WANG Yasong, QIU Yanyu, WANG Mingyang, YUE Songlin, WANG Jianping, DENG Shuxin

2023, 44(S1):  170-179.  doi:10.12382/bgxb.2023.0739

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Due to a large number of pores inside the calcareous sand, the calcareous sand is usually in a three-phase saturated state, and its liquefaction characteristics are significantly different from the fully saturated state. The large-scale explosion model of three-phase saturated calcareous sand is test out by using a self-developed device. The explosion liquefaction characteristics of calcareous sand under three-phase saturation is analyzed. A long-term dissipation model of excess pore water pressure of three-phase saturated calcareous sand is established. A dynamic liquefaction model is established for the characteristics of three-phase saturated calcareous sand, and the reliability of the model is verified by numerical simulation of explosion experiment. The research results can provide reference for the analysis of foundation stability and the construction of safety protection facilities after the explosion disaster in coastal islands.

Numerical Simulation of the Propagation Law of Explosion Shock Wave in Turning Tunnel

YU Wenjun, CHEN Shengyun, DENG Shuxin, YU Bingbing, JIN Dongyan

2023, 44(S1):  180-188.  doi:10.12382/bgxb.2023.0889

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Based on the LS-DYNA software, a single TNT explosion in a turning tunnel is simulated to verify the accuracy of the simulation using LS-DYNA, and the effects of the variable angle θ and the radius of curvature R on the propagation law of shock wave in the turning tunnel are studied. The results show that, when θ and R are small, the changes of θ and R have a greater effect on the changes of shock wave parameters at the tunnel deflection, and the effect is smaller at the far field; when θ is 90° and R is 0mm, the pressure on the outer wall surface at the deflection in the tunnel is 2.17 times of the pressure on the inner wall surface. With the increase of θ, the peak overpressure of the reflected shock wave decreases, and the energy distribution of the shock wave tends to change to the back tunnel, and the peak overpressure at the far field decreases first and then increases; with the increase of R, the reflection phenomenon of the shock wave at the change of direction is not obvious, and the peak overpressure of the reflected shock wave is low; and with the increase of θ and R, the difference between the peak overpressures of the reflected pressures received by the outer wall surface and the inner wall surface decreases. When θ and R are increased to a certain degree, respectively, the effect of changing θ and R on the change of shock wave parameters in the whole tunnel is not obvious, but the pressure on the outer wall surface is still slightly higher than that on the inner wall surface.

Construction of Scaled Model of Reinforced Concrete Column Based on Dimensional Analysis

WANG Jia, YIN Jianping, LI Xudong, YI Jianya, WANG Zhijun

2023, 44(S1):  189-195.  doi:10.12382/bgxb.2023.0716

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Taking the typical reinforced concrete columns as the main research object, the similarity law relationship of reinforced concrete columns under explosive loading is derived based on similarity theory and dimensional analysis method. The different scaled models are established using the finite element simulation software LS-DYNA for numerical simulation to verify the similarity law relationship. The dimensional analysis method is used to obtain a relationship formula of similarity law, which can be used to calculate and convert the deflection of a column in an equal proportion; By comparing the calculated results of similarity law and the numerically simulated results, it is found that the error of maximum displacement in the column is less than 10%. This indicates that the accuracy of the established similarity law relationship satisfies engineering applications, which can provide some help for later scholars to study the damage of concrete columns under explosive loading of steel bars.

Application of Intelligent Logistics Equipment in Dark Factory of Explosive Production

HE Aijun, LIU Yinlian, YU Jing, JIA Fan

2023, 44(S1):  196-208.  doi:10.12382/bgxb.2023.1000

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The use of machines to replace people and achieve automated and intelligent logistics is a necessary path for the construction of dark factories in the current explosives industry. The equipment in explosive Dark Factory consist of four categories, manufacturing equipment, detection equipment, logistics equipment and management system. The main function of logistics is inventory management, inbound and outbound management, and automatic transportation. The logistics system must meet the requirements of automated data collection, inbound and outbound management, scheduling, and digital management. From raw materials to final products, the logistics of explosives Dark Factory can be classified into three categories based on their basic functions: loading and unloading, transportation, and storage. For storage, it is recommended to use automated warehouses, automated containers, etc. For transportation, it is recommended to use automatic guided vehicles, rail guided vehicles, etc. For loading and unloading, it is recommended to use robot arms, unmanned forklifts, etc. A solution for infrared wireless communication and QR code communication was proposed without the foundation of 5G network. The research results indicate that, under the basic requirements of confidential communication and explosion-proof, selecting or customizing appropriate logistics equipment from storage, transportation, loading and unloading, etc. according to the characteristics of the production line, can gradually build a Dark Factory that meets the special requirements of explosive production.