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第十届全国冲击动力学讨论会

第十届全国冲击动力学讨论会

  • 召开年：2011
  • 召开地：太原
  • 出版时间： 2011-07

主办单位：中国力学学会;北京理工大学

会议文集：第十届全国冲击动力学讨论会论文集

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  • 摘要：运用准静态材料试验机、SHPB压杆、轻气炮/VISAR实验系统，在从准静态到一维应变飞片撞击的应变率范围内对7075铝等材料进行了材料动态响应特性实验测试，获得了在此应变率范围内材料屈服流动的应变率效应曲线。结果表明，在低应变率（～＜102s-1）和高应变率（～＞104s-1）条件下材料屈服强度的应变率效应微弱，而在应变率约1.6×103s-1附近一个很小的区间内，材料屈服强度对应变率非常敏感。金属材料的这种应变率效应敏感区间的存在是常见的，但经典的Johnson-Cook本构模型及其多种改进形式均不能对此做有效的描述。根据国内外研究文献和本文的试验研究，作者提出一种Johnson-Cook模型的改进形式。这种唯象的本构模型在从10－4s－1到106s－1的应变率范围内可以对材料动态强度应变率效应敏感区间现象进行单一形式的唯象表达，适用于大多数的金属材料。
  • 摘要：水下近距离爆炸会使结构产生严重的局部毁伤，单层结构很难对水下近距离爆炸实现有效防御。本文作者根据水下爆炸产生的各种载荷及其对结构的作用特点，建立了多层结构模型，进行了一系列模型试验，在此基础上对模型毁伤范围、毁伤吸能规律以及结构参数对毁伤效应的影响进行了分析，得到了规律性的结果，对于深入研究在接触爆炸条件下多层结构的破坏、开展水下抗爆防护结构设计均具有重要的学术价值。
  • 摘要：使用万能材料试验机、扭转试验机、霍普金森拉杆和Taylor撞击实验研究了高强铝合金2A12在常温~250 ℃的准静态，动态本构关系和失效模型。基于实验结果，修改了Johnson-Cook强度模型中的应变强化项以及Johnson-Cook失效模型中的温度软化项，并结合数值仿真得到了模型参数。实验结果表明，2A12铝合金的应变强化效应和温度软化效应显著，而应变率硬化效应不显著；失效应变随温度的增加、应力三轴度的减小和应变率的增加而增加。
  • 摘要：水下爆炸壁压测量一直是水下爆炸载荷测试的难点。本文以电气石晶片为敏感元件，设计并研制了水下爆炸壁压传感器，通过自由场压力测试对传感器进行了标定，进而对气背平板表面压力进行了测量。试验获得了完整的压力时程曲线，并对测量波形进行详细分析，解释所观察到的现象，认为研制的传感器可以用于水下爆炸壁压的测量，即本满足壁压测量的需要。
  • 摘要：基于动力响应一致的原则，提出了将典型建筑物构件所遭受的爆炸载荷等效为无升压时间的三角形均布载荷的方法。首先，采用量纲分析将典型构件的最大动量及其达到时间作为等效参数，得到了构件的等效载荷超压峰值和持续时间与炸药当量和爆距之间的无量纲经验关系式。通过在一定无量纲范围内，对不同构件力学性能、几何条件、爆炸当量以及爆炸距离的工况数值计算结果进行拟合，确定了经验表达式中的常数。最后，采用数值方法对等效载荷和实际爆炸载荷作用下构件的动力响应数值分析结果的进行比较，验证了该等效方法的有效性。
  • 摘要：基于中国船舶科学研究中心冲击爆炸试验室历年来有关水面船（试验物分别为实船、船模和浮动冲击平台）上设备在水下爆炸作用下测量得到的冲击响应数据，本文首次推导得出一个简单有用的设备冲击响应实验预报公式。接着运用F-分布和相关系数这两种检验方法分别对上述公式进行了回归检验，两种检验结果均表明这个公式用于预报水面船上设备抗冲性能的置信度是非常高的。
  • 摘要：利用非线性有限元软件Abaqus对一种新型桥墩防护装置在碰撞条件下的变形吸能情况进行了数值模拟研究，确定了保护壳厚度、撞击点高度等因素对装置防护效果的影响。验证了桥墩在安装该装置后，在与车辆发生碰撞的时，能够保持桥墩稳定性与安全性。
  • 摘要：基于流体动力学关系式，讨论了不同状态方程在不同冲击波强度下冲击波波后压强增量，计算了正入射时反射强度与入射强度之间的关系；给出了斜冲击下正规反射时反射角与入射角之间的关系，以及反射强度与入射角之间的关系，并把不同状态方程的结果进行了对比。结果表明：正入射时，熵增条件下的反射强度低于等熵过程的反射强度；斜入射时，在正规反射条件下，反射角随入射角的增大而增大，随入射强度的增大而增大，反射强度与入射强度的比值随入射角的增大而增大，随入射强度的增大而增大。
  • 摘要：冲击波的聚焦可以在聚焦区域形成局部较高的压力。通过理论分析与数值模拟，分析了水下冲击波的聚焦过程；采用通用有限元软件ANSYS/LS-DYNA建立了一种水下冲击波聚焦的有限元模型，将高压放电等效为爆炸源，模拟得到了冲击波传播的演变过程、压力历史及轴线上的压力分布及峰值压力；分析了聚焦区域负压产生的原因，并对状态方程进行了改进，改进后得到的结果与实验结果吻合较好。
  • 摘要：深井软岩具有独特的力学特性，受到动态载荷更为突出，其动态力学性能对于工程加固及稳定性具有重要意义。利用分离式霍布金森实验系统对泥岩、砂质泥岩和细砂岩等三种典型软岩进行单轴动态压缩实验。实验结果表明，软岩的加载波形曲线中入射波的形状比较稳定，反射波与透射波的形状与岩石试样的孔隙率密切相关；随着应变率的增加，碎块尺度显著减小，碎块数量明显增加，表现出较强的应变率相关性；软岩动态变形、初始弹性模量、峰值应力等与应变率显著相关；入射波、反射波和透射波所携带的能量随时间增加而均增加，达到某一能量值后近似保持恒定，能量耗散随应变率的增加而显著减小。
  • 摘要：采用直锥变截面霍普金森压杆压杆研究了混凝土/加筋混凝土的动态拉伸性能。分析了不同应变率下加筋混凝土试件的破坏模态，考察了配筋率和配筋方式对混凝土/加筋混凝土动态拉伸强度的影响。实验结果表明，存在一临界应变率，当应变率超过该值时，其抗拉强度有较大比例的增加，加筋混凝土的动态拉伸强度明显高于素混凝土，且随着配筋率的增加，其动态抗拉强度显著增大。研究结果对钢筋混凝土材料的工程应用具有一定的指导意义。
  • 摘要：分别对木材顺纹、横纹径向、横纹弦向垂直于被保护体的包装箱结构正、30°斜冲击行为进行数值模拟，结果表明木材能通过自身塑性变形和破坏耗散能量，实现对被保护体的缓冲作用。云杉木材沿顺纹、横纹径向和弦向具有不同压缩缓冲性能，在变形一定情况下，沿具有较高平台应力顺纹方向加载吸收的能量最大，而沿径向和弦向加载吸收的能量基本相等；在耗能一定情况下，顺纹方向加载产生的变形最小，沿径向和弦向加载产生的变形最大。数值分析结果和云杉不同方向压缩吸能曲线均表明，木材放置方式对包装箱撞击过程中的缓冲性能有很大影响，合理的木材排列方式主要取决于包装箱质量、被保护体能承受的应力、变形极限、撞击速度等条件，对于低速小变形冲击情况，采用木材顺纹垂直于被保护体产生的缓冲效果较好；对于高速大变形情况，木材径向或弦向应垂直于被保护体更利于缓冲吸能。
  • 摘要：The dynamic behavior of simple supported rectangular thin plate subjected to transverse harmonic excitation is investigated in this paper. The compressive loads N1 andN 2 is applied on edges of the plate. On assumption of small deformation, dynamic governing equation is derived. The constitutive relation of material obeys can be stood foran integral equation. By use of nonlinear Galerkin method, the partial differential governingequation is turned into integral-differential variation of the buffing equation. The different kinds of behaviors are investigated making use of the classical tools of nonlinear dynamics, such as the phase portrait, the time-displacement history and Lyapunov exponent analysis. The results of analysis show that the values of N 1 and N2，character time of materialhave large influence on the dynamic response. When they satisfy some condition, chaotic motions may occur in the dynamic system.
  • 摘要：Magnesium alloy is very attractive in many industrial applications due to its low density The structure-property relationships of the magnesium alloy under quasi-static loading have been extensively investigated. However, the dynamic behavior, particularly the mechanism of high-rate plastic deformation, of the magnesium alloy requires more in-depth investigations. In this paper, the effect of aging treatment on the quasi-static and dynamic properties of a typical rare earth Mg-Gd-Y magnesium alloy is investigated. In particular, the plastic deformation mechanism under由namrc compression loading is discussed. Split Hopkinson Pressure Bar (SHPB) was used to carry out dynamic compression tests with controllable plastic deformation by using stopper rings. The experimental results demonstrate that both static and dynamic properties of the Mg-Gd-Y alloy vary under various aging treatment conditions (under-aged, peak-aged and over-aged conditions), due to two different kinds of second phases：remnant micro size phase from solid solution treatment and nano precipitation from aging treatment. The results of microstructure characterization and statistic analysis of the metallographic phase are presented. The area fraction of the twinned grains increases due to aging treatment and dynamic loading. The main plastic deformation mechanism of the rare earth Mg-Gd-Y magnesium alloy is possibly dislocation slip, rather than twinning for the conventional AZ31 magnesium alloy under high strain rate loading.
  • 摘要：The fragmentation of rock induced by impact loading is one of typical nonlinear problems in underground engineering rock specimen such as rock plate was found to become invalid under impact loading. This paper presents brittle fragmentation for dynamic damage of rock plate based on the edge-on impact (EOM test with vary impact velocity (10 ms-' to 40 ms-') and impact angle and describes and explains this dynamic weakness phenomenon. High-speed camera was used to study the relation among crack initiation and propagation, impact velocity and impact angle. The results demonstrate that only a damaged zone appeared on the edge of the sample when the impact velocity is less than a critical value, its size increased with the increase of the impact velocity：when the velocity exceeds the critical value, some radial cracks occur around the damaged zone and extend outward from the boundaries of damaged zone. The radial crack length and damaged zone increase with impact velocity and are influenced by the impact angle. However, at a certain velocity, suddenly, the damage zone decreases and the crack length increases, it shows that there was an obvious incubation period of crack forming. According to test results, the study found that the impact velocity of this jump is about 25 ms-130 ms-1 and the scope of impact resistance optimized angle is about 150-300.
  • 摘要：The penetration depth of rigid projectiles is investigated using the modified spherical cavity expansion theory and the HJC model for the concrete targets, in wluch the model parameters used in the Molw-Coulomb Tresca-limit yield criterion are obtained by the triaxial compression tests. By comparing the cavity expansion pressures of the concrete samples with two different types of aggregate, the influence of the aggregate hardness on the penetration processes is discussed. With the analysis of the tractions acted on the projectile nose, the influences of the projectile and target material properties as well as the projectile struchme on the transition impact velocity are also discussed. By comparing the theoretical results with the experimental data, two penetration mechausms are demonstrated for the ogive-nose projectile penetration into concrete with the striking velocities np to 2.Okm/s
  • 摘要：A series of tensile tests for pure copper sheets containing drilled holes of multi-configurations are carried out on a tensile split Hoplinson bar (TSHB) at a range of tensile velocities. The dynamic growth and coalescence of drilled voids were recorded by a high-speed camera.The results of scanning electron microscopical (SEM) investigation of microvoid evolution at edges of ruptured zones between drilled voids in recovered sheets show void coalescence mechanisms, which are similar to evolution of visualized drilled voids. The experimentally recovered and high-speed camera recorded evolution of drilled voids in pure copper sheets are compared with the numerical simulations involving different models for void coalescence in order to overcome the difficulty of assessing the validity of available models for void coalescence. The possibility of application of Thomason model and Brown-Embury model for void coalescence to thermoviscoplastic material was explored under impact tension.
  • 摘要：The crystal plasticity model for low-symmetric (3-HMX single crystals with only limited operative slip systems has been developed, accounting for nonlinear elasticity, volumetric coupled with deviatoric behavior, and thermodynamical consistency. Based on the decomposition of the stress tensor, the modified equation of state for anisotropic materials is adopted. Simulation results of the planar impact onp-HMX single crystals show good agreement with existing experimental data by Dick and Hooks (2004). In addition to providing new perspective to a range of orientation-dependent shock behaviors ofp-HMX single crystal, the present research also discusses dislocation density, shear stress and strain localization, and anisotropic temperature increase inshockedp-HMX single crystals under shock loading. The proposed formulation and algorithms can also be applied to other low symmetric crystals under impact or shock loading which gives irrecoverable deformation by crystallographic slip. Temperature calculations with various characteristic features for different orientations based on numerical simulations are explained, but no comparison with available experimental data is possible to our knowledge. Future studies should also examine phase changeand twining as they also often occur in IMX single crystals.
  • 摘要：The validity of the constant propagation fracture energy postulation for dynamic fracture is discussed. As shown from existing direct and indirect experimental results, thisassumption may not represent the prisical reality. For spontaneous fractures, the fracture energy was shown to increase linearly with the crack length, and for dynamic fractures driven by known amplitude impulsive loading (generated by planar impact), the fracture energy was not a constanteither. Despite of its phenomenogical origin, the Broberg's theory developed for self-similar crack growth works well for both spontaneous fractures and for dynamic fractures produced by well defined dynamic loading. In this theory, the fracture energy is not a constant. Furthermore, withgiven far-field loading or equivalent far-field loading, the crack speed is uniquely determined by a strength-like material parameter. This parameter is related to the cohesive strength proposed by H.J. Gao for perelastic materials in the crack-tip process zone. It is proposed in this work that the strength-like parameter (or equivalently the constant fracture speed) is a better material parameter to describe the dynamic fracture propagation process.
  • 摘要：A spherical cavity expansion model for concrete is first proposed by using an elastic-brittle-plastic material law with Hoek-Brown strength criterion. The constitutive model can capture the basic features of the mechanical response of concrete materials including the effects of strain-softening and pressure hardening (pressure-dependent shear strength) and all the parameters used in the model can be determined from material tests. The forcing function obtained from the spherical cavity expansion analysis is then employed to construct a penetration model for concrete targets struck by ogival-nosed projectiles. It transpires that the present model predictions are in good agreement with experimental observations in terms of penetration depth and ballistic limits/residual velcoties in the case of perforation.
  • 摘要：The nonlinear governing equations of dynamic post-buckling of cylindrical shells are obtained aid the energy method and Hamiltonian system. Based on eigensolutions of the linear pre-buckling of the shells in Hamiltonian system, the nonlinear post-buckling of the shells, which are impacted by radial pulse loads, is discussed. The problem is reduced to the expandedness of eigensolutions and the computation of recursion formulas. For computing, the mode of the pre-buckling is considered as the initial mode. The evolvement process of the post-buckling is revealed. The results show that the influences for the amplitude of the initial mode is less in some thickness of shells, whereas, the post-buckling behaviors of shells are sensitive to the thickness and the length of shells, the intension time of pulses.
  • 摘要：In this paper, the dynamic behavior of rectangular plate under the loading of parameter cycle is studied. The partial differential equation based on the mechanical model is established, which be simplified into two ordinary differential equations utilizing Galerkin method. The existence of 1/2 harmonics solutions of dynamical system applying the harmonic balance method is analyzed. The amplitude-frequency relationship is determined_ and the stability of solutions is confirmed.
  • 摘要：This paper bases on the prototype of the actual shed tunnel structure, study on contact force, displacement, damage, energy of shed tunnel under impact of rock-fall. By ABAQUS finite element software to simulate the process of roll-fall impact knowable：Rock-fall at different speeds and incident angle shocks on shed tunnel has great influence to concrete protective structure of contact force and displacement；Concrete protective structure damage the worst hit area of occurred with roll-fall contact area, the second is inclined leg column top and in connection with the pillars of the beam damage is also very serious, In practical projects first should pay attention to strengthen the intensity of the pillars with beam joints and prevent damage：From the angle of energy we can see that shed tunnel is mainly through the concrete protective structure to absorb and consumption impact energy, soil cushion absorption and consumption impact energy is very limited, to alleviatethe impact of concrete protective layer rolling damage, and suggestions in shed tunnel bearing place additional energy shock absorber to increases protection structure system soft degrees under the condition of minimize the shed tunnel weight, achieve the purpose of decrease shock energy.
  • 摘要：This paper establishes a model of heat conduction and thermodynamic responses of a spherical cavity under shocks ofboth heat and pressure whose distributions versus time are arbitrary. By using the Laplace transform，it deduces the closed form formulas of temperature and radial displacement of the cavity. It also briefly analyzes the meanings of the displacement expression. As special examples, the displacement formula can be simplified to the results of Refs and, respectively.
  • 摘要：In order to investigate the ignition mechanism of HTPB propellants under high pressure waterjet, HTPB propellant of different formulas was used under high-pressure water jet impact research, conducted SEM analysis and infrared spectra analysis to the propellant before and after impact. The results showed that the surface morphology and composition of HTPB propellant was changed during the process of the impact of high-pressure waterjet, and propellant was chemical changed, and the composition of ammonium perchlorate and ferrocene affected the chemical change significantly.
  • 摘要：super-detonation with higher detonation pressure, velocity and local sound velocity is paid more attention for its potential application for hyper-velocity launch technique. Multi-stage detonation acceleration system takes advantage of strong detonation to accelerate flyer to high velocity. In this paper, numerical simulation is done for the research on effects of materials of flyers on the propagation property of piston-supported detonation to find the best one which could be used as the material of flyers in the multi-stage detonation system.
  • 摘要：将圆柱壳体视为理想刚塑性材料，分析了自由圆柱壳在中部受到刚性弹体撞击时的塑性动力响应过程，给出了圆柱壳的塑性运动速度和刚体运动速度。针对典型算例，给出了自由圆柱壳在受到侧向撞击时的刚体运动速度和位移的变化历程，并应用Ls-dyna进行了数值模拟。两者有较好的一致性。
  • 摘要：DDAM是舰船设备抗冲击计算的主要手段，基于模态理论和冲击谱方法，简单易算，方便实用，被世界上各主要海军国家广泛使用，然而其主要缺陷是在计算过程中无法考虑系统的非线性特性。目前的舰船上大量使用隔振缓冲元件来降低辐射噪声和提高抗冲击能力，系统在冲击作用下，隔振缓冲元件会表现出刚度硬化或软化特性，这给DDAM计算结果带来很大的误差。为了使DDAM方法能够较准确地分析具有非线性刚度特性的舰船设备的冲击性能，使DDAM方法能够在方案设计和初步设计阶段对带有非线性刚度的设备进行抗冲击计算，作者提出了一种非线性刚度等效线性刚度的近似计算方法，利用隔振器吸收能量相等的准则进行等效计算，计算结果同时域非线性增量计算结果进行了比较，得到了一些有益的结论。
  • 摘要：与舰船抗冲击技术相关的试验能力在很大程度上体现了一个海军国家舰艇抗冲击能力的强弱，其中设备抗冲击能力是舰船战时生命力的一个重要指标。目前，为保证舰船设备的抗冲击能力，我国海军要求装舰设备在上舰之前必须经过冲击试验考核，经冲击试验考核合格后的设备方可安装到舰艇上。我国的GJB150.18-86规定了不同重量等级的舰船设备必须在不同的试验装置上进行冲击试验考核，该标准沿用了美国MIL-S-901C的要求进行编制的。以前的试验能力只能进行质量小于2.7t舰船设备的冲击试验考核，随着我国加大对舰船设备抗冲击试验考核设施的投入力度，我国已经建成了能满足GJB150.18-86进行重型设备冲击试验考核的标准浮动冲击平台。本文主要分析了标准浮动冲击平台的冲击环境要求及其在浮动冲击平台开展舰船设备标准考核试验的方法。
  • 摘要：本课题组近期开展了两组先进钻地弹缩比弹高速侵彻混凝土实验，计入弹载测试装置，弹重约1.8kg，撞击速度在1130m/s~1650m/s之间。采用H100火炮为加载手段，结合次口径技术，测量弹体的侵彻深度与质量损失等。进一步分析表明，弹体无量纲侵深在30以上，质量损失仍与初始动能成正比，且剩余弹体形状的计算结果与实验结果吻合。侵彻后弹形基本完整，验证了该弹形高速侵彻时良好的结构稳定性。
  • 摘要：为研究真实航空发动机风扇断叶撞击机匣的响应机理，在高速旋转试验台上进行包容试验。使用ANSYS/LS-DYNA建立网格精细、材料模型及参数合理的有限元模型进行了数值仿真，得到与试验数据吻合较好的计算结果。研究表明，该型航空发动机一级风扇机匣是非包容的；非包容性过程可以分为三次连续的撞击，第一次为叶尖与机匣内壁的刮擦，第二次为机匣包容区的鼓包形成及鼓包的破裂，第三次为机匣的带状撕裂和弯曲；鼓包破裂的失效模式为双向拉伸失效；而鼓包变形为机匣的主要吸能模式。
  • 摘要：根据考虑弯矩剪力及轴力的刚塑性屈服条件和塑性铰之间的线性速度分布假设，给出侧向冲击荷载作用下固端梁动力响应数学模型的建立原理及其非线性不同阶微分方程组数值求解方法步骤。编制相应程序进行计算，通过与钢管混凝土侧向冲击实验成果数据的对比分析，表明本文建立的数学模型可精准预测冲击塑性变形特征，提出的微分方程组数值求解方法是稳定可靠的。
  • 摘要：利用ф35炮和ф100炮采用次口径发射技术完成了金属混凝土等遮弹材料的系列试验。从完成的抗侵彻试验效果分析，作为一种新型高强高性能材料，金属混凝土用于遮弹层克服了现有遮弹层存在的不足之处，其综合遮弹效果明显优于其它遮弹材料或结构。
  • 摘要：污泥的处理和最终处置是环境科学中所面临的一个重大难题，利用炸药爆炸产生的冲击波可以破坏污泥（含水率大于95%）的胶体结构，提高污泥的脱水率，促进污泥的厌氧消化，对解决此项难题有积极的作用。利用球形爆炸容器测试了炸药在污泥中爆炸时的超压情况，得出超压规律，并测试了爆炸容器壁部应变。实验结果对污泥处理的定量分析及球形爆炸容器水下爆炸提供了依据。

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