International Journal of Impact Engineering最新文献_第3页

Comparative investigation of shock pressure, shock duration, pressure decay time, and elastic energy of both porous gelatin and pure gelatin in shock state 多孔明胶和纯明胶在冲击状态下的冲击压力、冲击持续时间、压力衰减时间和弹性能量的比较研究

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-19 DOI: 10.1016/j.ijimpeng.2024.105148

Jiayi Li , Xiongwen Jiang , Hongjian Wei , Yue Li , Wei Zhang

Bird strike is an unavoidable threat in the aviation industry. Real birds are typically replaced with 10 wt. % pure gelatin or porous gelatin to simplify bird strike experiments and meet repeatability requirements. Porous gelatin is obtained by adding chemical agents to gelatin solution, which then solidifies, it can be regarded as pure gelatin filled with tiny pores. The differences in shock state characteristics between these two substitutes remain unclear.

In this paper, flyer plate impact experiments are conducted separately for the two types of gelatin, obtaining

u_{s} - u_{p}

Hugoniot. Considering the continuous release waves, the analytical solutions are provided for the pressure decay time and elastic energy anywhere within the gelatin, during the shock state. Numerical models of gelatin strike rigid target are conducted to extract the shock pressure and elastic energy during the shock state. The differences in mechanical properties of gelatin are analysed to understand that result in variations in pressure, shock duration, decay time, and elastic energy.

It is evident that the shock pressure of pure gelatin is higher than that of porous gelatin. The shock duration of porous gelatin is longer, and its smaller bulk modulus causes the release wave more gradual, resulting in longer shock decay time. The analytical solution of pressure decay time tends to be overestimated, the faster expansion of porous gelatin during pressure release exacerbates this discrepancy, resulting in a greater difference between the analytical solution and numerical model of elastic energy.

鸟击是航空业不可避免的威胁。为了简化鸟击实验并满足重复性要求，通常用 10 重量%的纯明胶或多孔明胶代替真鸟。多孔明胶是通过在明胶溶液中添加化学试剂而得到的，凝固后可被视为充满微孔的纯明胶。本文分别对这两种明胶进行了飞碟板冲击实验，获得了向上的Hugoniot。考虑到连续释放波，本文提供了冲击状态下明胶内部任何位置的压力衰减时间和弹性能量的解析解。建立了明胶撞击刚性目标的数值模型，以提取冲击状态下的冲击压力和弹性能量。分析了明胶机械性能的差异，以了解压力、冲击持续时间、衰减时间和弹性能量的变化。多孔明胶的冲击持续时间较长，其较小的体积模量使释放波更加渐进，从而导致冲击衰减时间较长。压力衰减时间的解析解往往被高估，而多孔明胶在压力释放过程中更快的膨胀加剧了这一差异，导致解析解与弹性能量数值模型之间的差异更大。

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引用次数: 0

Evaluation of compression behaviour of 316L SS Gyroid and Diamond structures using SLM process – Experimental programme under static and dynamic compression loadings 使用 SLM 工艺评估 316L SS Gyroid 和 Diamond 结构的压缩性能 - 静态和动态压缩载荷下的实验方案

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-16 DOI: 10.1016/j.ijimpeng.2024.105147

Grégory Haugou, Hervé Morvan, Jean Dominique Guérin, Eric Markiewicz

The relative comparison in terms of energy absorption efficiency for a set of 4 structures made of various Triply Periodic Minimal Surfaces (TPMS) topologies is experimentally investigated. These TPMS structures are printed by Selective Laser Melting AM process using 316L SS. The study is carried out in consideration of the effect of parameters such as relative density, compressive loading directions and loading rates, number of unit cells for Diamond and Gyroids TPMS both declined for Sheet and Skeletal topologies. The objective is to quantify their structural responses in terms of apparent stress and strain, dynamic enhancement and Specific Energy Absorbed (SEA) and to evaluate their structural integrity in terms of collapse stability. The results reveal that the Sheet pattern of TPMS structures with its constant wall thickness and uniform geometry exhibits better energy absorption capabilities than the Skeletal pattern. The Diamond family shows greater interest rather than the Gyroid family only in the case of the Sheet pattern. The increase in relative density from 20 to 30 % is characterised by improved manufacturing quality, an increase in energy absorption capacity and more homogeneous progressive deformations during compression. On the whole, the set of TPMS geometries exhibits energy absorption capacities prior to those of other conventional cellular materials currently used for impact engineering applications. Finally, in a first approach, an original design methodology using charts can be developed to establish a link between the energy absorption capabilities and the design geometric parameters of TPMS structures.

实验研究了由各种三周期最小表面（TPMS）拓扑结构组成的一组 4 个结构在能量吸收效率方面的相对比较。这些 TPMS 结构是使用 316L SS 通过选择性激光熔融 AM 工艺打印而成的。研究考虑了各种参数的影响，如相对密度、压缩加载方向和加载速率、菱形和陀螺型 TPMS 的单元格数量，以及片状和骨架状拓扑结构。研究的目的是从表观应力和应变、动态增强和比能量吸收（SEA）方面量化它们的结构响应，并从坍塌稳定性方面评估它们的结构完整性。结果表明，具有恒定壁厚和均匀几何形状的片状 TPMS 结构比骨架式结构具有更好的能量吸收能力。在片状结构中，菱形结构比陀螺型结构更受关注。相对密度从 20% 增加到 30%，其特点是制造质量提高，能量吸收能力增强，压缩过程中的渐进变形更加均匀。总体而言，这套 TPMS 几何结构的能量吸收能力优于目前用于冲击工程应用的其他传统蜂窝材料。最后，在第一种方法中，可以利用图表开发一种原创的设计方法，在能量吸收能力和 TPMS 结构的设计几何参数之间建立联系。

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引用次数: 0

Structural response of steel-concrete composite panels to near field simultaneous blast and fragmentation loading 钢-混凝土复合板在近场爆炸和碎片同时加载下的结构响应

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-15 DOI: 10.1016/j.ijimpeng.2024.105142

Jia Yuan Lim , Chong Yik Melvin Goh , Kok Wei Kang , Jun Li , Chengqing Wu

Steel-concrete composite sandwich panels are used in blast doors or blast walls to protect personnel and equipment in explosive environments due to their superior performance against blast effects. In the design of such panels, most design methods treat blast and fragment loading independently for far-field explosions. However, the synergistic effects of combined blast and fragments loading should be accounted for in close-in explosion scenarios. In this study, a field test program was conducted to assess the damage of the steel-concrete composite panels subjected to close-in explosion of cased charges at various scaled distance between 0.39 and 0.78 m/kg^1/3. Characterization test of cased charge detonation was performed to explore the combined loading effect. The analysis includes the pressure-time history from the cased charge detonation, distribution of the fragment masses and velocities over the test panels. The structural damage and response of the composite panels against the combined loading effects was measured. The results indicated that in addition to the damage from the blast wave, the panel was remarkably damaged by the fragment impact. Despite the significant structural damage, the panels maintained its structural integrity after the tests. Additionally, quasi-static load tests were conducted on the panels to quantify their load resistant differences in pristine condition and various damaged conditions due to the explosive effects.

钢-混凝土复合夹层板因其优异的抗爆性能，被用于防爆门或防爆墙，以保护爆炸环境中的人员和设备。在设计此类板材时，大多数设计方法都将远场爆炸的爆炸荷载和碎片荷载分开处理。然而，在近距离爆炸情况下，则应考虑爆炸和碎片组合加载的协同效应。在本研究中，我们进行了一项现场试验计划，以评估钢-混凝土复合板在 0.39 至 0.78 m/kg1/3 的不同比例距离内受到套管炸药近距离爆炸的破坏情况。为探究综合加载效应，还进行了套管炸药爆炸的特性测试。分析包括套管装药起爆的压力-时间历史、碎片质量分布以及在试验面板上的速度。测量了复合材料板在联合加载效应下的结构损伤和响应。结果表明，除了爆炸波造成的破坏外，面板还受到碎片冲击的严重破坏。尽管结构受到严重破坏，但试验后面板仍保持了结构完整性。此外，还对面板进行了准静态负载测试，以量化其在原始状态和因爆炸影响而受损的各种状态下的抗负载差异。

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引用次数: 0

Dynamic response of double-layer rectangular sandwich plates with graded foam cores under blast loading 带有分级泡沫芯材的双层矩形夹层板在爆炸荷载下的动态响应

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-15 DOI: 10.1016/j.ijimpeng.2024.105141

Yao Wang , Yafei Guo , Jianxun Zhang

In this paper, dynamic response of a fully clamped double-layer (DL) rectangular sandwich plate with graded foam cores (GFC) under blast loading is studied theoretically and numerically. Based on the yield criterion, an analytical model for dynamic response of a DL rectangular sandwich plate with GFC is established under blast loading. With the use of the inscribing and circumscribing squares of the exact yield locus, the bound of the analytical solution of the dynamic response of a double-layer rectangular sandwich plate with GFC is obtained. By neglecting the effect of bending moments, the membrane mode solution of a DL rectangular sandwich plate with GFC in large deflection is obtained. Finite element analysis (FEA) is performed using ABAQUS/Explicit software. The effects of interlayer factor, average yield strength of graded foams, and gradient properties of graded foams on the dynamic response of DL rectangular sandwich plate with GFC are considered. The analytical predictions are in excellent accord with the numerical ones. It is demonstrated that the proposed analytical model is effective to predict the blast response of a DL rectangular sandwich plate with GFC.

本文从理论和数值上研究了带有分级泡沫芯材（GFC）的全夹紧双层（DL）矩形夹层板在爆炸荷载下的动态响应。根据屈服准则，建立了带有 GFC 的 DL 矩形夹层板在爆炸荷载下的动态响应分析模型。利用精确屈服点的嵌入方形和圆周方形，得到了带有 GFC 的双层矩形夹心板动态响应解析解的边界。通过忽略弯矩的影响，得到了带有 GFC 的双层矩形夹心板在大挠度下的膜模解。使用 ABAQUS/Explicit 软件进行了有限元分析（FEA）。考虑了层间系数、分级泡沫的平均屈服强度和分级泡沫的梯度特性对带 GFC 的 DL 矩形夹层板动态响应的影响。分析预测结果与数值预测结果非常吻合。结果表明，所提出的分析模型能有效预测带 GFC 的 DL 矩形夹层板的爆炸响应。

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引用次数: 0

Prediction of low-velocity impact responses for bio-inspired helicoidal laminates based on machine learning 基于机器学习的生物启发螺旋形层压板低速冲击响应预测

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-11 DOI: 10.1016/j.ijimpeng.2024.105144

Wenhao Liu, Hu Liu, Zhengqiang Cheng, Hailing He, Qianhua Kan, Guozheng Kang

The inherent capacity of natural protective systems to withstand impact loadings, attributed to their microscale helicoidal architectures, has garnered significant interest. Drawing inspiration from this mechanically robust design, this study aims to introduce the composite laminates with a helicoidal distribution and to accurately and efficiently predict their Low-Velocity Impact (LVI) responses. Initially, the Latin hypercube design (LHS) was employed to generate 500 samples representing various pitch angles. An experimentally verified finite element model was then established to capture the load-displacement curves and energy-time curves for these 500 samples. Subsequently, the Convolutional Neural Network (CNN) model was utilized to accurately predict the load-displacement curves and energy-time curves for bio-inspired helicoidal laminates across different pitch angles. The principal component analysis (PCA) was used to enhance the efficiency of learning the load-displacement and energy-time curves in a reduced dimensional space, and the SHapley Additive exPlanations (SHAP) method was employed to investigate the feature importance of pitch angle. Finally, the helicoidal laminate with the highest energy absorption for a given volume was obtained by the genetic algorithm (GA) combined with the CNN model. This optimized laminate demonstrates a remarkable 9.5 % improvement in energy absorption compared to the best-performing sample within the original data set. Furthermore, the "spiraling" delamination damage of the helicoidal laminates was studied, which indicates that the delamination with small pitch angle is more pronounced for that with large pitch angle. The proposed method offers significant advantages in terms of cost reduction and efficiency enhancement for predicting the LVI responses of helicoidal laminates, holding immense potential in structural design and optimization of composite materials.

天然防护系统因其微米级的螺旋结构而具有抵御冲击载荷的内在能力，这引起了人们的极大兴趣。本研究从这种机械坚固设计中汲取灵感，旨在引入具有螺旋分布的复合材料层压板，并准确有效地预测其低速冲击（LVI）响应。首先，采用拉丁超立方设计（LHS）生成 500 个代表不同俯仰角的样本。然后建立一个经过实验验证的有限元模型，以捕捉这 500 个样本的载荷-位移曲线和能量-时间曲线。随后，利用卷积神经网络（CNN）模型准确预测了不同螺距角的生物启发螺旋形层压板的载荷-位移曲线和能量-时间曲线。利用主成分分析法（PCA）提高了在降维空间中学习载荷-位移曲线和能量-时间曲线的效率，并采用 SHapley Additive exPlanations（SHAP）方法研究了螺距角特征的重要性。最后，通过遗传算法（GA）与 CNN 模型相结合，得到了在给定体积下能量吸收最高的螺旋形层压板。与原始数据集中表现最好的样本相比，这种优化层压板的能量吸收能力显著提高了 9.5%。此外，还研究了螺旋形层压板的 "螺旋 "分层损伤，结果表明，小螺距角的分层比大螺距角的分层更明显。所提出的方法在降低成本和提高效率方面具有显著优势，可用于预测螺旋形层压板的 LVI 响应，在复合材料的结构设计和优化方面具有巨大潜力。

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引用次数: 0

Assessment of bending waves in Torsion Hopkinson Bar experiments using Photon Doppler Velocimetry 利用光子多普勒测速仪评估扭转霍普金森棒实验中的弯曲波

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-11 DOI: 10.1016/j.ijimpeng.2024.105139

Lukasz Farbaniec , Yuan Xu , Junyi Zhou , Duncan Macdougall , Sophoclis Patsias , Nik Petrinic , Clive Siviour , Antonio Pellegrino , Daniel E. Eakins

A Photon Doppler Velocimetry system that measures the propagation of elastic shear waves in a Torsion Hopkinson Bar (THB) system is presented. The method uses multiple fibre optic probes located symmetrically on opposing sides of the apparatus bars, and provides data with high spatial (a laser irradiated spot size of

35 μ m

) and temporal resolution that is ultimately limited by the data acquisition system and used electronic components. A series of validation experiments simulating the movement of the bar subjected to bending and misalignments demonstrated that this approach is effective in detecting and accounting for the bending waves. The THB experiment under non-ideal conditions, where a combination of shear and bending waves propagates in the system, conclusively confirmed that the disturbance in the acquired signals can be properly addressed with the proposed arrangement of the PDV probes. It was reflected in similar measurements of the component of tangential velocity to the strain gauges. This approach shown to be complementary to the conventional strain gauge technique, but can provide better precision and be more robust under loading and/or temperature conditions that may affect the reliability of strain gauge measurements.

本文介绍了一种光子多普勒测速系统，用于测量扭转霍普金森棒（THB）系统中弹性剪切波的传播。该方法使用多个光纤探头，对称安装在仪器杆的对立面，可提供高空间分辨率（激光照射光斑尺寸为 35μm）和时间分辨率的数据，但最终受限于数据采集系统和使用的电子元件。一系列模拟棒材在弯曲和错位情况下运动的验证实验表明，这种方法能够有效地检测和解释弯曲波。在系统中传播剪切波和弯曲波的非理想条件下进行的 THB 实验最终证实，采用所建议的 PDV 探头排列方式，可以正确处理所采集信号中的干扰。应变片切线速度分量的类似测量结果也反映了这一点。这种方法是对传统应变计技术的补充，在可能影响应变计测量可靠性的加载和/或温度条件下，可以提供更高的精度和更强的稳定性。

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引用次数: 0

Impact response of 3D printed cornstalk-inspired structures: The effect of indenter shape on penetration 三维打印玉米秸秆启发结构的冲击响应：压头形状对穿透力的影响

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-10 DOI: 10.1016/j.ijimpeng.2024.105143

Shakib Hyder Siddique , Paul J. Hazell , Gerald G. Pereira , Hongxu Wang , Juan P. Escobedo

This paper reports the mechanical response and damage tolerance of 3D-printed cornstalk-inspired structures subjected to impact loading. Specimens were subjected to dynamic indentation tests at multiple impact energies with flat, hemispherical, and conical indenters. The mechanical properties of the base material (ABS) were measured across varying strain rates using a Shimadzu® Universal Testing Machine and a Split Hopkinson Pressure Bar. The effect of geometrical variations of the constituents on energy-absorbing capability was also investigated. Damage characteristics were interrogated through X-ray CT scans and provided detailed failure modes associated with each indenter shapes. Further, finite element simulations provided insights into the penetration mechanisms associated with the different indenter shapes. The results demonstrated that test specimens impacted by flat indenters absorbed ∼25 % less energy than those impacted by hemispherical and conical indenters. Among the various indenters, the conical shape had the highest duration of contact force within the specimen before experiencing failure by matrix cracking and complete perforation.

本文报告了三维打印的玉米秸秆启发结构在承受冲击载荷时的机械响应和损伤耐受性。使用平面、半球形和锥形压头对试样进行了多种冲击能量下的动态压痕测试。使用岛津® 万能试验机和分体式霍普金森压力棒测量了基体材料（ABS）在不同应变速率下的机械性能。此外，还研究了成分的几何变化对能量吸收能力的影响。通过 X 射线 CT 扫描检查了损伤特征，并提供了与每种压头形状相关的详细失效模式。此外，有限元模拟还提供了与不同压头形状相关的穿透机制。结果表明，与半球形和锥形压头相比，受到扁平压头冲击的试样吸收的能量要少 25%。在各种压头中，圆锥形压头在试样内的接触力持续时间最长，然后才会出现基体开裂和完全穿孔的失效。

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引用次数: 0

Cold Temperature Effects on the Impact Behaviour of Glued-Laminated Timber Beams 低温对胶合层压木梁冲击行为的影响

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-09 DOI: 10.1016/j.ijimpeng.2024.105135

Nicole Wight , Christian Viau , Patrick Heffernan

Engineered wood products, such as glued-laminated timber (glulam), have been and are continuously being utilized in the construction of tall timber buildings and notable landmark bridges. This infrastructure, particularly the latter, may be exposed to hazardous impact loads throughout their service life. As little research has been conducted on the impact behaviour of glulam beams under cold temperature conditions, there is a need to investigate the potential effects of impact loading on glulam structural elements at cold temperatures. This paper presents an experimental investigation aimed at understanding the effects of cold temperatures on the impact behaviour of glulam timber beams. Fifteen glulam beams were tested under quasi-static and impact loading, under ambient and cold temperatures. Drop weight impact testing was performed to simulate dynamic loading conditions similar to those experienced in real-world scenarios. The results indicate that both the loading regime and cold temperatures have a significant influence on the strength and stiffness of glulam beams, whereby statistically significant increases in the moduli of rupture and elasticity were observed, however, no interaction between the two variables occurred. A single-degree-of-freedom (SDOF) model was developed and validated using the experimental test results and found to provide good accuracy.

胶合层积材（胶合木）等工程木制品已经并将继续用于建造高大的木结构建筑和著名的地标性桥梁。这些基础设施，尤其是后者，在其整个使用寿命期间都可能面临危险的冲击载荷。由于对胶合梁在低温条件下的冲击行为研究甚少，因此有必要研究低温条件下冲击荷载对胶合结构构件的潜在影响。本文介绍了一项实验研究，旨在了解低温对胶合木梁冲击行为的影响。在环境温度和低温条件下，对 15 根胶合木梁进行了准静态和冲击载荷测试。通过落重冲击测试，模拟了与实际情况类似的动态加载条件。结果表明，加载制度和低温对胶合梁的强度和刚度都有显著影响，据统计，胶合梁的断裂模量和弹性模量都有显著增加，但这两个变量之间没有相互作用。利用实验测试结果开发并验证了单自由度（SDOF）模型，发现该模型具有良好的准确性。

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引用次数: 0

Experimental and 3D mesoscopic numerical simulation study of kinetic projectile penetrating into concrete 动能弹丸穿透混凝土的实验和三维介观数值模拟研究

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-06 DOI: 10.1016/j.ijimpeng.2024.105140

Zhiyan Yao , Feng Qin , Jinzhu Li , Xihuang Zhang , Fenglei Huang

Concrete is a multiphase composite material composed of mortar, aggregate, and interface transition zone (ITZ). The mesoscopic components of concrete have an important influence on its anti-penetration performance. In this study, a series of penetration experiments with large-caliber ogive-nosed projectiles penetrating concrete targets are carried out. The test results show that the damage to the concrete target consists of crater and tunnel zones and increases with increasing impact velocity. Then, a local background grid method is proposed to establish a 3D mesoscopic model of concrete, based on the arrangement characteristics of the sequence number of the finite elements. Compared with the traditional 3D mesoscopic concrete modeling method, the proposed method can effectively improve the modeling efficiency. Subsequently, numerical simulations are performed based on the 3D mesoscopic model, with the simulation and experimental results in good agreement, verifying the effectiveness of the model. Finally, the verified 3D mesoscopic model is employed to investigate the effects of shape, volume fraction, size interval, and strength of the concrete aggregates on the depth of penetration (DOP) and deflection of the projectile. The simulation results indicate that the shape of the aggregate has a negligible effect on both uniaxial compressive strength and DOP. Therefore, spherical aggregates are used to improve modeling efficiency. Increasing the volume fraction and strength of the aggregates can significantly enhance the anti-penetration performance of concrete. The influence of aggregate size interval on DOP is slight, but it has a significant impact on projectile and trajectory deflection at the same aggregate volume fraction. The uneven lateral resistance on both sides of the projectile, caused by the random distribution of aggregates, is a major factor in deflection.

混凝土是一种由砂浆、骨料和界面过渡区（ITZ）组成的多相复合材料。混凝土的中观成分对其抗穿透性能有重要影响。在本研究中，进行了一系列大口径椭圆鼻射弹穿透混凝土目标的穿透实验。试验结果表明，对混凝土目标的破坏包括弹坑区和隧道区，并且随着冲击速度的增加而增加。然后，根据有限元序列号的排列特征，提出了一种局部背景网格方法来建立混凝土的三维网格模型。与传统的三维网格混凝土建模方法相比，所提出的方法能有效提高建模效率。随后，基于三维网格模型进行了数值模拟，模拟结果与实验结果吻合良好，验证了模型的有效性。最后，利用经过验证的三维介观模型研究了混凝土骨料的形状、体积分数、尺寸间隔和强度对弹丸穿透深度（DOP）和挠度的影响。模拟结果表明，骨料的形状对单轴抗压强度和 DOP 的影响微乎其微。因此，使用球形骨料可提高建模效率。提高骨料的体积分数和强度可以显著提高混凝土的抗渗透性能。骨料粒径间隔对 DOP 的影响很小，但在骨料体积分数相同的情况下，对弹丸和弹道挠度的影响很大。骨料的随机分布造成弹丸两侧侧向阻力不均，是影响挠度的主要因素。

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引用次数: 0

High strain-rate fracture behavior of a hollow projectile 空心弹丸的高应变速率断裂行为

IF 5.1 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Impact Engineering

Pub Date : 2024-10-06 DOI: 10.1016/j.ijimpeng.2024.105138

Chang Soo Lee , Jeong Whan Yoon , Sang Hyun Woo , Lee Ju Park

In this paper, a hollow projectile made of AISI4340 steel was fabricated based on an arbitrary warhead shape, and high-speed impact tests were performed according to various target encounter conditions including velocity and angle. In order to characterize the dynamic fracture behavior, tensile tests were performed on various notch specimens under three strain rates (10^–3 s^-1, 10⁰ s^-1, 10³ s^-1), and the stress state histories of the specimens were calibrated through a hybrid experimental-numerical analysis. In particular, for the intermediate (10⁰ s^-1) and high (10³ s^-1) strain rate conditions, the local temperature rose due to adiabatic heating until fracture was experimentally measured, and the thermal softening behavior determined from the inverse optimization technique was considered for the dynamic constitutive model. For the comparison with the high-speed impact test results, a rate-dependent ductile fracture model was utilized for numerical simulation. Considering that the model parameters were calibrated with the thermal softening effect, the proposed fracture model implicitly takes temperature into account. The deformation and fracture modes of the projectile from experimental and numerical study showed very good agreement under all impact conditions. It was confirmed that the softening of a material by adiabatic heating should be considered along with strain rate hardening in dynamic fracture simulation.

本文根据弹头的任意形状制作了由 AISI4340 钢制成的空心弹丸，并根据各种目标遭遇条件（包括速度和角度）进行了高速冲击试验。为了表征其动态断裂行为，在三种应变速率（10-3 s-1、100 s-1、103 s-1）下对各种缺口试样进行了拉伸试验，并通过实验-数值混合分析对试样的应力状态历史进行了校准。其中，在中应变率（100 s-1）和高应变率（103 s-1）条件下，通过实验测量了绝热加热导致的局部温度升高直至断裂，并在动态构成模型中考虑了反优化技术确定的热软化行为。为了与高速冲击试验结果进行比较，采用了与速率相关的韧性断裂模型进行数值模拟。考虑到模型参数是根据热软化效应校准的，因此所提出的断裂模型隐含地考虑了温度因素。在所有冲击条件下，实验和数值研究得出的弹丸变形和断裂模式都非常吻合。实验证实，在动态断裂模拟中，材料的绝热加热软化应与应变速率硬化一并考虑。

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引用次数: 0