共查询到19条相似文献,搜索用时 281 毫秒
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借助ANSYS/LS -DYNA程序,采用ALE方法描述炸药和空气场,采用Lagrange方法描述玻璃,玻璃除考虑拉应力失效外,还增加了切应变失效判据,并给出了针对不同玻璃的建模方法和计算参数。利用建立的模型对爆炸冲击波对钢化夹胶玻璃、普通夹胶玻璃和浮法玻璃3种常用建筑玻璃的作用过程进行了数值模拟。计算结果可较好地反映实验中玻璃出现的冲切破坏现象,发生破坏时的冲击波超压也与实验结果吻合。研究表明,钢化玻璃比普通玻璃具有更强的抗爆性能,夹层玻璃中的PVB能有效地阻止玻璃的飞溅。 相似文献
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为研究爆炸冲击波对钢化玻璃的毁伤阈值,开展了钢化玻璃冲击波毁伤效应实验。对每一发实验进行了爆炸参数测试,获得了冲击波超压随时间变化历程的实验数据。通过对实验数据的处理与分析,得到了爆炸冲击波基本参数,包括正反射超压、冲击波到时、正压作用时间、正反射冲量、负反射超压、负压作用时间和负反射冲量等。将实验结果与CONWEP计算结果进行了比较,比较结果表明二者误差很小,证明冲击波测试结果准确可靠。对冲击波正负反射参数进行了比较,结果表明冲击波正反射参数明显高于冲击波负反射参数。 相似文献
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球形装药动态爆炸冲击波超压场计算模型 总被引:1,自引:0,他引:1
为获得球形装药动态爆炸冲击波超压场计算模型,对静态爆炸冲击波超压Baker计算公式加入修正因子进行修正,并建立了构造包含装药运动速度、对比距离和方位角的修正因子函数的方法。为获得修正因子的函数表达式,采用高精度显式欧拉流体动力学软件SPEED针对具有典型运动速度的球形装药空中爆炸过程进行了数值模拟,得到了沿装药不同对比距离和方位角处的动态爆炸冲击波超压峰值。在对数值模拟结果处理的基础上,经过数据拟合获得了动态爆炸冲击波超压场计算模型。校验结果表明,该模型能较准确描述动态爆炸冲击波超压分布,具有普适性。 相似文献
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爆炸冲击波下导弹结构动力分析模型初步研究 总被引:2,自引:0,他引:2
针对爆炸冲击波对导弹目标毁伤这一复杂问题进行了合理的简化,研究了冲击波对导弹结构的破坏问题。利用动力学知识,估计了冲击波对导弹目标的机械破坏作用。在综合考虑战斗部装药质量、爆炸点距目标距离、爆炸高度的环境压力、目标几何尺寸以及目标抗冲击载荷能力等基础上,利用自行编制的程序进行了一系列的仿真计算,得出了战斗部在不同时间不同位置和不同装药质量下产生的冲击波对导弹产生的破坏。计算结果基本符合物理规律,说明采用的模型及算法是合理的,能够对目标在爆炸冲击波超压作用下的易损性进行评估,得到的计算结果对实际应用具有参考价值。 相似文献
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P.A. Hooper R.A.M. Sukhram B.R.K. Blackman J.P. Dear 《International Journal of Solids and Structures》2012,49(6):899-918
Blast resistant glazing systems typically use laminated glass to reduce the risk of flying glass debris in the event of an explosion. Laminated glass has one or more bonded polymer interlayers to retain glass fragments upon fracture. With good design, the flexibility of the interlayer and the adhesion between layers enable laminated glass to continue to resist blast after the glass layers fracture. This gives protection from significantly higher blast loads when compared to a monolithic pane. Full-scale open-air blast tests were performed on laminated glass containing a polyvinyl butyral (PVB) interlayer. Test windows of size 1.5 m × 1.2 m were secured to robust frames using structural silicone sealant. Blast loads were produced using charge masses of 15 kg and 30 kg (TNT equivalent) at distances of 10–16 m. Deflection and shape measurements of deforming laminated glass were obtained using high-speed digital image correlation. Measurements of loading at the joint, between the laminated glass and the frame, were obtained using strain gauges. The main failure mechanisms observed were the cohesive failure of the bonded silicone joint and delamination between the glass and interlayer at the pane edge. A new finite element model of laminated glass is developed and calibrated using laboratory based tests. Predictions from this model are compared against the experimental results. 相似文献
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The failure mechanism of a concrete slab–soil double-layer structure subjected to an underground explosion was investigated by experimental and numerical methods in this paper. Two underground explosion depths of 150 and 350 mm were tested. The typical failure modes such as the conoid spall of concrete, the bulge of the concrete slab and the cavity in the soil were obtained experimentally. Numerical simulations of the experiments were performed using a hydrodynamic code to analyze the effects of both the stress wave and the expansion of the blast products. Based on the experimental and numerical results, the effects of explosive depth, blast wave front and expansion of the blast products on the failure modes and failure mechanisms were discussed. The underground explosion process at different explosion depths was also analyzed. The results show that attenuation of the stress wave in the soil is significant. The blast wave front and the expansion of the blast products play different roles at different explosion depths. At the explosion depth of 150 mm, the failure mode is mainly caused by a point load induced by the blast wave front, whereas at the depth of 350 mm a sphere-shaped load resulting from the expansion of the blast products is a key factor for failure. 相似文献
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Fracture mechanics of laminated glass subjected to blast loading 总被引:2,自引:0,他引:2
A failure criterion based on energy balance approach is introduced for the laminated glass panel subjected to blast loading. Based on this failure criterion, a damage factor is developed to assess the failure of the laminated glass panel. If the damage factor is less than one, the plate is safe otherwise unsafe. Trigonometric function is employed to express the transverse deflection and the Airy’s stress function in von Karman’s large deflection equations of a thin plate. The nonlinear ordinary differential equation of motion obtained using the Galerkin method is solved using Runge–Kutta method. The predicted results indicate that the breakages of the laminated glass may be caused by the negative phase of the blast load if the positive phase blast load is not violent enough to cause failure. Also, the size of glass shards the laminated glass plies breaks in to is predicted using the surface energy based failure model. 相似文献
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Yao Guowen Liu Zhanfang Huang Peiyan 《Acta Mechanica Solida Sinica》2006,19(1):69-74
The failure wave has been observed propagating in glass under impact loading since 1991. It is a continuous fracture zone which may be associated with the damage accumulation process during the propagation of shock waves. A progressive fracture model was proposed to describe the failure wave formation and propagation in shocked glass considering its heterogeneous meso-structures. The original and nucleated microcracks will expand along the pores and other defects with concomitant dilation when shock loading is below the Hugoniot Elastic Limit. The governing equation of the failure wave is characterized by inelastic bulk strain with material damage and fracture. And the inelastic bulk strain consists of dilatant strain from nucleation and expansion of microcracks and condensed strain from the collapse of the original pores. Numerical simulation of the free surface velocity was performed and found in good agreement with planar impact experiments on K9 glass at China Academy of Engineering Physics. And the longitudinal, lateral and shear stress histories upon the arrival of the failure wave were predicted, which present the diminished shear strength and lost spall strength in the failed layer. 相似文献
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通过有限元软件LS-DYNA建立了舱内爆炸载荷下箱型舱室动响应数值模型,并借助文献试验结果验证了数值模型的可靠性,研究了平板型、内凹型、外凸型、箭头型、箭矢型、背面弧型等6种角隅连接结构对舱内爆炸载荷下箱型舱室变形、特征位置压力和破坏模式的影响,分析了内爆效应下角隅连接结构的失效机理。数值结果表明:舱壁角隅位置是舱内爆炸载荷作用下舱室易发生破坏撕裂的特征位置;相比无连接结构,平板型连接结构对舱壁最大塑性变形改善最大,降低幅度达到了31.9%;背面弧型连接结构能够使箱型舱室角隅等效塑性应变降低约60%;设置连接结构能够改变高塑性应变的发生位置,进而改变箱型舱室的破坏模式;采用平板型、内凹型、背面弧型连接结构的箱型舱室能够有效避免角隅失效破坏。 相似文献
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金属柱壳破坏过程与材料、结构及载荷等相关,断裂结果呈现多种形式,采用有限元结合实验对不同爆炸载荷作用下,TA2钛合金圆管的破坏机制开展研究。有限元结果显示:对于理想均质柱壳,由于冲击波传播使壁厚中间形成二次塑性区,圆管壁厚中部的等效塑性应变总是大于内、外壁。在较高爆压下,裂纹在加载阶段从试样壁厚中部起始,沿45°或135°向内外壁剪切扩展;而在较低爆压下,破坏发生在自由膨胀阶段,断裂从内壁起始向外壁剪切扩展,两者破坏过程和机制不同,总体来说,与实验现象符合较好。相关实验中出现的一些外壁拉伸断裂现象,可能与试样的几何、材料缺陷等因素相关,其对金属圆管爆炸破坏的影响值得进一步关注。 相似文献
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J. W. McCauley E. Strassburger P. Patel B. Paliwal K. T. Ramesh 《Experimental Mechanics》2013,53(1):3-29
Structural transparent material systems are critical for many military and civilian applications. Transparent armor systems can consist of a wide variety of glass laminate assemblies with polymeric bonding interfaces and backing as well as the inclusion of polycrystalline ceramic (AlON, spinel) and single crystals (sapphire) as front facing materials. Over the last 20 years as the threats have escalated and become more varied, the challenges for rapidly developing optimized threat specific transparent armor packages have become extremely complex. Ultimate failure of structural ceramics in impact events is a function of the temporal and spatial interaction of the macro-stresses at the macro-, micro- and nano-structural scale, including elastic and inelastic (plastic) deformation, crack nucleation, damage evolution and resulting failure from the macro-scale (top down) and/or from the nano-scale (bottom up). In order to accelerate the development of validated design and predictive performance models, a systematic series of experimental investigations have been carried out on various non-crystalline ceramics (glass), single crystal (sapphire) and polycrystalline ceramics (AlON). The Edge-on Impact (EOI) test coupled with a high-speed Cranz-Schardin film camera has been extensively used on a variety of monolithic and laminated glasses, AlON and crystallographically controlled sapphire single crystals to visualize and quantify stress wave, crack and damage propagation. A modified Kolsky bar technique instrumented with a high speed digital camera has been utilized in an unconfined and confined test sample mode to examine the dynamic deformation and failure of AlON undergoing uniaxial, high strain rate compression. Real time photography has clearly demonstrated the critical influence of defects and post mortem characterization of fragments resulting from these tests have revealed the influence of micro-deformational twining and cleavage down to the nano-scale. Finally, a brief summary of work using ultra-high-speed photography of the impact of conventional projectiles on glass and AlON will be presented. These experimental results will be absolutely critical to help evolve and validate existing models used in computer codes to simulate the impact performance of brittle materials. 相似文献