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2025, Volume 46, Issue 5

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Special Issue on Impact Dynamics
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Special Issue on Impact Dynamics

Preface

QU Jia, CHEN Rong, ZHANG Lei, LEI Hongshuai

2025, 46(5): 1-2.

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Abstract:

Parametric Analysis and Parameter Inversion of the Crystal Plasticity Constitutive Model for as-Cast TiZrNbV Refractory High Entropy Alloys

MA Peiyuan, LIN Yuliang, CHEN Rong

2025, 46(5): 563-581. doi: 10.21656/1000-0887.450264

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Abstract:
Refractory high-entropy alloys (RHEAs) have attracted considerable attention due to their outstanding mechanical properties. However, the influence of their microstructural behavior on macroscopic mechanical performance remains poorly understood. With the increase of study on material micromechanical behaviors, the crystal plasticity finite element methods become essential tools for uncovering the underlying mechanisms of crystalline materials. Since crystal plasticity constitutive models involve numerous complex parameters, a thorough analysis of these parameters is critical for a deeper understanding of the micromechanical behaviors of alloys. The crystal plasticity model used in this study incorporates the Peierls stress, which accounts for the short-range potential barriers of the material, thereby enabling a more accurate simulation of its strain-rate behavior. Through experimental design and range analysis, the key constitutive parameters affecting the alloy's mechanical properties were identified. Univariate analysis was then employed to clarify the specific effects of these critical parameters on the mechanical characteristics of the material. For parameter inversion, an optimization-based approach was developed, combining the support vector regression with optimization algorithms. This method effectively inverts crystal plasticity constitutive parameters from macroscopic mechanical testing data. For the cast TiZrNbV alloy, a set of optimal parameters was successfully inverted, and the agreement between simulation results and experimental data validated the method's effectiveness. This study provides valuable insights for predicting the mechanical behaviors, guiding material design, and optimizing the performances of refractory high-entropy alloys.

Design and Optimization Study on Blast Resistance of Irregular Lattice Structure Base Floor

ZHANG Hao, DUAN Shengyu, FU Rui, PENG Xiaoyang, LEI Hongshuai

2025, 46(5): 582-590. doi: 10.21656/1000-0887.450294

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Abstract:
A new type of irregular lattice structure base floor was proposed, and its blast resistance was characterized and optimized. The parametric modeling program for the lattice structure base floor was developed, the blast responses of the base floor were analyzed based on the finite element method, the surrogate model between the lattice structure geometrical parameters and the blast resistance responses was established, and the rapid solution of the fitness function was realized. A multi-objective optimization design method for the blast responses of the lattice structure base floor was developed, and the lightweight design of the lattice structure was achieved. The finite element analysis results show that, the optimized design of the lattice structure base floor achieves a 24.1% weight reduction and a 41.7% blast resistance improvement at the same time. This study provides methodological support and technical guidance for the design and application of irregular blast-resistance equipment such as armored vehicle base floors.

Study on the Influence of Deformation Mode Assumption on Plastic Deformation of Circular Plates Under Impact Loading

XU Weizheng, HUANG Yu, LI Tong, LI Yexun, FU Hua, WANG Yanping, ZHENG Xianxu

2025, 46(5): 591-599. doi: 10.21656/1000-0887.450285

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Abstract:
To find a reliable and universal plastic deformation mode of circular plates under impact loading, based on the energy method, a plastic deformation calculation model for circular plates under impact loading was established, with different deformation modes and material strain rate effects considered. Then the calculation model was compared with the experimental results to analyze the calculation deviation of plastic deformation of circular plates under different deformation modes. The results show that, different deformation mode assumptions give different spatial distributions of membrane tensile strain and different membrane tensile average strain rate effects, which changes the energy absorption characteristics of plastic deformations and finally affects the plastic deformation values of circular plates. The parabolic deformation mode has the advantages of small errors and wide application ranges for materials, and is suitable for the subsequent engineering evaluation.

Study on Dynamic Mechanical Properties and Anti-Explosion Performances of Tempered Glass

LIU Hao, JIA Bin, KONG Defeng, ZHANG Lei

2025, 46(5): 600-610. doi: 10.21656/1000-0887.450283

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Abstract:
As an essential construction material, the tempered glass has important research value and engineering application background for study on the failure law and protective performance under accidental strong dynamic loads such as explosion, earthquake, collision and typhoon. Experimental investigations on the quasi-static and high strain rate mechanical properties of tempered glass were conducted with the MTS (materials testing system) and the split Hopkinson bar (SHPB), respectively. The parameters of the JH-2 constitutive model were calibrated and the model's accuracy was verified. The simulation was conducted to investigate the failure processes of tempered glass panes under different overpressure peaks and different impulse shock waves with the LS-DYNA software. The failure scaled radius of the tempered glass pane is about Z=4 m · kg^-1/3. As the stand-off distance decreases, the pane tends to be safe; however, as this distance increases, the damage degree significantly rises. This indicates that, the failure of tempered glass panes depends not only on the peak overpressure but also on the impulse.

Numerical Simulation of Stand-Off Distance Effects on Explosive Welding Quality of Titanium-Stainless Steel

MIAO Guanghong, WU Weida, ZHOU Dapeng, DONG Jilei, WEI Zhengmei, CHEN Long, ZHU Zhiqiang

2025, 46(5): 611-620. doi: 10.21656/1000-0887.450301

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Abstract:
The effects of stand-off distance on explosive welding quality between titanium (TP 270C) and stainless steel (SUS 821L1) composite plates, were investigated. The 3D numerical simulations were conducted with the ANSYS/LS-DYNA software by 2 algorithms (the ALE method and the SPH-FEM coupling method) for 3 stand-off distances: 1.2 mm, 2.2 mm and 3.5 mm. The simulation results show that, for both algorithms the vertical displacements of flyer plates reach or exceed respective stand-off distances. The collision velocities and angles consistently fall within the acceptable range of the welding window. The collision velocity and angle exhibit positive correlations with increasing stand-off distances. Optimal welding quality occurs at the 3.5 mm stand-off distance. The results verify that both algorithms effectively simulate explosive welding between the TP 270C titanium alloy and the SUS 821L1 stainless steel. Stable bonding is achievable across all tested stand-off distances. Moreover, the interfacial bonding strength increases progressively with the stand-off distance, which demonstrates an enhancement mechanism in welding quality through parameter optimization.

Impact Damage Characteristics Simulation of Steel Fiber Reinforced Concrete With the GDEM Software

ZHANG Jin, QI Zhigang, ZHANG Lei

2025, 46(5): 621-632. doi: 10.21656/1000-0887.450311

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Abstract:
Steel fiber-reinforced concrete (SFRC) is the most utilized structural material for protective engineering. It is frequently subjected to complex stress states with high strain rates under strong dynamic loads, such as explosions and penetrations. Most current studies on the dynamic mechanical properties of SFRC are limited to 1D stress and 1D strain loading conditions. However, the impact-compression characteristics under 3D stress states are still scarce. Herein the GDEM-BlockDyna numerical simulation software was employed to simulate the damage modes of SFRC under confining pressures and investigate the concrete dynamic mechanical properties. The results indicate that, the peak stress and peak strain of SFRC both increase to different extents with the strain rates. The confining pressure reduces the rate effect on the impact compression strength of SFRC. The GDEM can realistically simulate the effects of strain rate and confining pressure on the dynamic mechanics of materials. In comparison to the finite element method, the GDEM is more effective in simulating the behaviors of steel fiber reinforced concrete, from its intact state to destruction. Furthermore, the GDEM can accurately describe the destruction stage characteristics of SFRC after the peak stress.

Crashworthiness of Polygonal Rotary Splicing Origami Tubes Under Oblique Low-Speed Impact Loads

TENG Chenhao, LIU Kunpeng, SONG Zhibo, CHEN Jiayu, ZHOU Caihua, TU Xinhao, ZHU Dongmei

2025, 46(5): 633-649. doi: 10.21656/1000-0887.450336

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Abstract:
To improve the crashworthiness of automotive collision energy absorption boxes under oblique impact loads, a new-type origami tube with a polygonal rotary splicing origami pattern was designed based on conventional square tubes. The drop hammer impact experiment and numerical simulation analysis were conducted to prove the excellent crashworthiness of the new-type origami tube compared with the conventional square tube under impact load, with a high-crashworthiness diamond pattern finally produced. Additionally, the effects of geometric parameters on the crashworthiness of the new-type origami tubes were studied at different impact angles. The numerical results show that, the changes of the crease height ratios, length ratios and width-to-thickness ratios of the origami tube significantly affect the crashworthiness, and lead to different deformation modes. Under different impact angles, average force F_ave and initial peak force F_max of the new-type origami tube gradually decrease with the increase of impact angle θ, but the decline trend of F_max is more significant than that of F_ave, and the origami tube still shows a relatively high crush load efficiency under different impact angles, to further verify that the polygonal rotary splicing origami tube has excellent oblique impact energy absorption performance.

Study of Dynamic Loading Tests on Low-Impedance Specimens

YIN Jianping, ZHANG Chenxu, SUN Ruoheng, CHEN Xixi, MIAO Yinggang

2025, 46(5): 650-660. doi: 10.21656/1000-0887.450279

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Abstract:
The key problems of the effective acquisition of low-impedance transmitted signals and the stress equilibrium in the Hopkinson bar loading tests on low-impedance specimens with high strain rates, were investigated. Based on the previous research fundaments, low-impedance elastic transmitted bars were introduced to replace the traditional metal transmitted bar, the in-situ calibrated semiconductor strain gauge technology was used to amplify weak transmitted signals, and the low-impedance specimens were tested with high precision. Reconstruction and calculation of the stress wave loading process were conducted to get the stress equilibrium history and the influential factors' sensitivity. The trapezoidal incident wave was proposed to realize stress equilibrium and achieve constant strain rate loading on specimens as early as possible. The results show that, low impedance polymethyl methacrylate bars/tubes as transmitted bars along with semiconductor strain gauges can acquire weak signals as low as several Newtons. The stress equilibrium history of the low-impedance specimen depends on the elastic wave velocity. Under the trapezoidal incident wave loading, the stress equilibrium and constant strain rate loading can be achieved at 2 characteristic periods. Based on the design of specimen thicknesses, the critical effective strain consistency can be achieved under different stress rate loadings.

Tests and Numerical Analyses of the Composite Casing Containment Under Hydrothermal Environment

ZHENG Jingbo, ZHANG Ying, JIANG Wenlong, WEI Lin, CHI Xue, YI Wenzhao, LIU Lulu, CHEN Wei

2025, 46(5): 661-675. doi: 10.21656/1000-0887.450289

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Abstract:
To obtain the inclusion characteristics of carbon fiber resin matrix composite casing in service environment, 2 high-speed impact ballistic tests were conducted before and after hygrothermal treatment, and the corresponding simulation model for the casing hygroscopicity partition hygrothermal test simulation model along with the finite element high-speed impact numerical simulation-analysis model, was established. The results show that, the hygrothermal treatment has significant effects on the impact resistance and energy absorption capacity of the carbon fiber resin matrix composite casing. Under the high-speed impact, the impact resistance and energy absorption capacity of the casing without hygrothermal treatment are better than those of the casing with hygrothermal treatment. The damage form of the casing under high-speed impact is dominated by the tensile failure of fiber and matrix, accompanied by a certain amount of fiber crush and in-plane shear failure, with little or no compression failure observed. The damage occurs in the vicinity of the impact area, and extends along the axial and circumferential direction of the casing. In addition, the tensile failure area of the matrix of the hygrothermally treated layer is significantly larger than that of the matrix of the untreated layer, which verifies the degradation of the mechanical properties of the matrix after hygrothermal treatment.

Thermal Impulse Response Analysis of Element Arrays in Flexible Electronic Devices

BIAN Chunyan, YANG Wencheng, MIAO Fuxing

2025, 46(5): 676-686. doi: 10.21656/1000-0887.460035

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Abstract:
The heat generated by flexible electronic devices during operation leads to deformation of the components, which is highly likely to affect their functionality. A finite element analysis model for the thermal impulse responses of the flexible electronic device element arrays were established, and the effects of the layer thickness ratio of the encapsulation layer to the substrate layer of the flexible electronic device element on the thermal stability of the overall structure, as well as the thermal impulse responses of the flexible electronic device components, were investigated. The results show that, the temperature of the functional layer center element rises by about 0.47% and the thermal stress increases by about 25.87% with the thermal impulse load increasing from 50 W/m² to 150 W/m². With the layer thickness ratio of the encapsulation layer to the substrate layer increasing from 0.2 to 5.0, the thermal stress of the functional layer center unit decreases by about 92%, the thermal strain decreases by about 99%, and the displacement along the layer thickness decreases by about 86%. The work provides basic data for the optimization design and protection against thermal impulse loading on flexible electronic device components.