共查询到17条相似文献,搜索用时 125 毫秒
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采用基于统一强度理论的有限柱形空腔膨胀理论,结合Tate磨蚀杆模型,考虑中间主应力、靶体侧面自由边界的影响及高速(1500 m/s~2200 m/s)侵彻弹体的变形和消蚀现象,推导线性硬化有限直径金属厚靶在长杆弹高速侵彻时的空腔壁径向应力,建立侵彻阻力和侵彻深度计算模型,并利用MATLAB软件编程求解,分析包括强度准则差异在内的弹道终点效应的一系列影响因素。结果表明:该文计算方法可以更好地描述弹靶的动态响应,还可以得到一系列基于不同强度准则的侵彻阻力和深度的解析解、对不同靶弹半径比的靶材侵彻深度的区间范围进行有效预测;强度参数、弹体撞击速度和靶体半径对有限直径金属靶体的抗侵彻性能均有较大的影响,其中强度参数值由1减小为0时,侵彻阻力可减小33.33%,侵彻深度可增加15.93%;当靶弹半径比小于等于20时,侵彻深度增大的程度显著,当靶弹半径比由19.88减小至4.9时,侵彻阻力减小了41.30%,侵彻深度增长了32.61%,此时靶体边界尺寸对侵彻性能的影响很大,不能继续按照半无限靶体进行计算。 相似文献
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考虑金属厚靶侧面自由边界的影响,研究了刚性尖头弹侵彻有限平面尺寸金属厚靶问题。基于有限柱形空腔膨胀理论和线性硬化材料模型,得到了空腔壁径向压力的解析式,建立了刚性尖头弹侵彻有限直径圆柱形金属厚靶工程模型。与试验和数值模拟比较表明,该文工程模型计算精度很好。基于所建立的工程模型,研究了靶板半径对侵彻深度和侵彻阻力的影响,结果表明:当靶板与弹丸半径比值小于20时,靶板半径对侵彻阻力和侵彻深度有显著影响,不能按无限尺寸靶板计算;当靶板与弹丸半径比值大于20时,靶板半径对侵彻阻力和侵彻深度影响较小,可近似按无限尺寸靶计算。 相似文献
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该文将统一强度理论与岩石材料动力强度依赖应变率效应的物理模型相结合,建立了岩石材料在侵彻等动力荷载作用下的率型动态统一强度准则。基于修正的土盘浮动锁应变模型,考虑应变率效应、中间主应力效应、强度准则差异和弹头滑动摩擦的影响,推导了土盘整体平均锁应力和整体平均锁应变的表达式。采用MATLAB数值计算软件和四阶Runge-Kutta算法编制计算程序,求解了中低速(V ≤ 900 m/s)长杆弹侵彻条件下弹体的侵彻深度,研究了侵彻过程中弹体的运动规律及靶体的动态响应,分析了各参数对弹体侵深的影响特性。研究表明:该文计算方法可以较好地描述整个侵彻过程中弹、靶的动态响应,还可以得到一系列基于不同强度准则的侵彻深度的解析解,有效地预测弹体侵深的上限值和下限值;中间主应力效应、强度准则差异和弹头滑动摩擦对岩石靶的抗侵彻性能具有重要影响。 相似文献
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基于一种新的细观离散元模型Lattice Discrete Particle Model(LDPM),该研究建立了刚性弹侵彻素混凝土厚靶的数值仿真模型。对LDPM基本假设和细观模型构建简单介绍,结合三轴压缩响应曲线,对23 MPa强度素混凝土进行LDPM参数标定。通过对比弹体减速度和侵彻深度试验值,验证数值模型对于混凝土厚靶侵彻问题的适用性。LDPM模拟弹体恒定速度侵彻混凝土厚靶,获得侵彻行程中侵彻阻力变化曲线,结合Forrestal阻力公式得到靶体静态阻应力。仿真结果表明,尖卵形弹头不同CRH值以及侵彻速度对靶体静态阻应力基本没有影响;弹径为最大骨料直径3倍、6倍和8倍的弹体受到靶体静态阻应力分别为260 MPa、175 MPa和163 MPa。该结果对混凝土侵彻缩比实验研究具有重要的实际工程意义。 相似文献
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基于一种新的细观离散元模型Lattice Discrete Particle Model(LDPM),该研究建立了刚性弹侵彻素混凝土厚靶的数值仿真模型。对LDPM基本假设和细观模型构建简单介绍,结合三轴压缩响应曲线,对23 MPa强度素混凝土进行LDPM参数标定。通过对比弹体减速度和侵彻深度试验值,验证数值模型对于混凝土厚靶侵彻问题的适用性。LDPM模拟弹体恒定速度侵彻混凝土厚靶,获得侵彻行程中侵彻阻力变化曲线,结合Forrestal阻力公式得到靶体静态阻应力。仿真结果表明,尖卵形弹头不同CRH值以及侵彻速度对靶体静态阻应力基本没有影响;弹径为最大骨料直径3倍、6倍和8倍的弹体受到靶体静态阻应力分别为260 MPa、175 MPa和163 MPa。该结果对混凝土侵彻缩比实验研究具有重要的实际工程意义。 相似文献
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《振动与冲击》2019,(1)
钢管约束混凝土在防护结构中具有广阔的应用前景。正六边形钢管约束混凝土靶具有优良的抗侵彻性能,其抗单发和多发打击性能明显优于半无限混凝土靶。为了研究钢管边长对抗侵彻性能的影响,进行了12. 7 mm钨芯穿甲弹(撞击速度600~836 m/s)侵彻不同边长正六边形钢管约束混凝土靶试验,得到了靶的破坏模式和主要损伤参数。结果表明:钢管边长对侵彻深度和侵彻阻力有较明显的影响,边长越小,侵彻深度越小,侵彻阻力越大;撞击速度约600m/s、钢管边长由66 mm减小到55 mm时,侵彻深度可减小约19%,侵彻阻力增大约17%;正六边形钢管约束混凝土靶的侵彻深度随着撞击速度的增大近似线性增加。 相似文献
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为研究异型头弹丸半侵彻金属靶的侵深特性,基于量纲方法对影响侵深的主控因素进行了分析,采用弹道枪加载和LS-DYNA软件对异型头弹丸半侵彻金属靶的作用过程进行了试验和数值模拟研究,分析了异型头弹丸结构、弹丸初速、靶板厚度等因素对侵彻深度的影响规律,获得了侵深随弹丸初速以及靶板厚度的变化曲线。研究结果表明,弹丸初速和靶板厚度是影响侵彻深度的关键因素,并拟合得到了弹丸初速和靶板厚度综合影响下的半侵彻侵深经验公式。研究结果可为半侵彻作用的研究及新型侵彻的工程计算方法等提供参考。 相似文献
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A unified strength criterion is applied for penetration analysis of geo-materials. Based on the cylindrical cavity-expansion theory the relation between the radial traction on the cavity surface and the impact velocity of a rigid projectile is derived. The finial penetration depth of the projectile is analytically obtained and the effect of strength criterion on the penetration depth is investigated. By comparing with existing test results, it is found that the proposed penetration model is effective in the analysis of a rigid projectile penetrating into a semi-infinite geo-material target. 相似文献
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Mass loss of an ogival projectile during its normal penetration in concrete target was investigated in this paper. Experiments of 38CrSi short-rod projectiles with ogival nose shape penetrating into concrete targets were conducted in the striking velocity range of 500–1500 m/s. Discussions revealed that projectile mass loss derives mainly from the nose part for both short-rod and long-rod projectiles during the penetration process. Furthermore, an engineering model was proposed to determine upper limit of rigid penetration regime as the maximum value of the striking velocity, which was based on the feature of projectile mass loss in the hydrodynamic transition between rigid penetration regime and semi-hydrodynamic penetration regime. Good agreements are obtained between engineering predictions and experimental results. 相似文献
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《International Journal of Impact Engineering》1996,18(5):465-476
We conducted depth of penetration experiments into grout and concrete targets with ogive-nose steel projectiles. Powder guns launched 0.064 kg, 12.9 mm diameter projectiles into grout targets with unconfined compressive strengths of 13.5 M Pa (2.0 ksi) and 21.6 MPa (3.1 ksi). For the concrete targets, powder guns launched projectiles with length-to-diameter ratios of 10; a 0.48 kg, 20.3 mm diameter rod, and a 1.60 kg, 30.5 mm diameter rod. Concrete targets had unconfined compressive strength of 62.8 M Pa (9.1 ksi) for the 0.48 kg rods and unconfined compressive strength of 51.0 MPa (7.4 ksi) for the 1.60 kg rods. For these experiments, penetration depth increased as striking velocity increased until nose erosion became excessive. Thus, we determined experimentally the striking velocities corresponding to maximum penetration depths. Predictions from a previously published model are in good agreement with data until nose erosion becomes excessive. 相似文献
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A new numerical–analytical model of penetration of long axisymmetric elastically deformable projectiles in semi-infinite targets is presented. A background of this model is the integral–differential equation of ballistics for non-deformable projectile. This equation is obtained on the basis of the Lagrange–Cauchy integral for non-stationary irrotational motion of an incompressible fluid, as well as the solutions for the quasi-static spherical cavity expansion problem in an infinite medium. The velocity field in a target is defined by actual projectile shape. The functional dependence of penetration velocity is determined for both elastic and rigid projectiles. The effect of forced elastic longitudinal oscillations on penetration velocity is estimated. An estimate is made for the critical impact velocity at which point the projectile plastically deforms causing irreversible changes in its shape, and also leads to instability of its trajectory in the target. This velocity depends on both elastic and strength characteristics of the projectile and target, their densities and projectile shape. Results from our penetration modeling are compared with existing experimental and calculated data. 相似文献
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We discuss the depth of cavities and craters caused by hypervelocity impacts as a function of impact parameters such as impact velocity, projectile and target densities, and projectile diameter, in two extreme cases: the penetration of intact projectiles at low impact pressure and the hemispherical excavation at very high impact pressure. The relations between the depth and the impact parameters are obtained. Then, previous experimental results are compiled; crater depth normalized by projectile diameter and the ratio of projectile and target densities is plotted for glass, plastic, and metal projectiles and metal, rock, ice, foam, sheet-stack, and aerogel targets. The trends of the data are consistent with the relations in the extreme cases. 相似文献