基于量纲分析的爆炸冲击波效应靶模型分析与实验研究

针对传统的冲击波压力电测法易受爆炸场寄生效应干扰问题,提出基于效应靶塑性变形的爆炸冲击波压力评定方法。由于效应靶理论模型复杂、参数较多,利用量纲分析方法简化模型获得爆炸冲击波压力作用的效应靶最大挠度与炸药TNT当量、炸高及炸距之关系,并建立冲击波压力作用的效应靶最大挠度计算模型;设计100 kg、60 kg、20 kg 三种标准TNT爆炸的立靶、平靶实验,用回归分析法获得二者经验模型系数。结果表明,立靶与平靶两种结构效应靶最大挠度实验结果与经验模型计算结果误差分别优于3.59%及3.33%。该研究可指导战斗部冲击波压力评估,进而减少爆炸实验量。     

Damage prediction of clamped circular plates subjected to contact underwater explosion

Contact explosion damage prediction of circular steel plates is of interest to the naval architects and warship designers. During contact explosion, a fraction of the explosive energy goes for plastic deformation and fracture of the plate. Experiments were conducted on air backed circular high strength low alloy (HSLA) steel plates to establish this fraction. There was a large amount of plastic deformation preceding fracture in the contact exploded plates. The deformation contour was found to be spherical showing maximum absorption of energy for the depth of bulge attained. The radius of penetration of the test plate was obtained by applying the terminal strain to fracture and the non-uniform strain distribution in the target plate. A case history is presented where the current predictions are compared with the existing empirical methodology and experimental data.     

爆炸冲击提高16Mn钢焊缝疲劳极限的机理

利用改变作炸药与取样部位间距离的办法，使初始组织结构和应力状态相同的１６Ｍｎ钢焊缝受到强度不同的冲击波作用。研究了焊炸处理前后冲击波作用弹性区。塑性区、弹一塑性形变交界区１６Ｍｎ钢焊缝的旋转弯曲疲劳性能及铁素体内位错结构和形态，提出了焊炸冲击改善焊缝疲劳极限的位错缠结的钉扎理论。     

一种改进的水下爆炸冲击波信号修正方法

爆炸载荷是舰船抗冲击设计和分析的基础,爆炸冲击波是表征炸药威力的一个关键物理量。在水下爆炸试验中,由于PCB138A50型电气石水下传感器在高频段存在失真,使得水下爆炸自由场压力信号存在上升沿、峰值失真的情况。当爆源与测点的水平距离远大于测点深度时,测点接收的信号需考虑反射波影响,一般会出现水面截断,形成驼峰现象。这都会使压力信号的冲击波能量计算产生误差,进而影响舰船的抗冲击分析。文章用Jensen提出的方法修正峰值,使用Cole函数对冲击波进行拟合修正。经对比,Cole函数拟合法比传统的指数拟合法修正后的冲击波能量更接近于试验炸药冲击波能量的理论值。     

低频簧片仪冲击特性与破坏规律分析

低频簧片仪是低频段冲击谱测量的主要装置,其结构为一组具有不同固有频率的集中质量悬臂梁。舰艇受到爆炸冲击时,集中质量悬臂梁易发生塑性变形或断裂,直接影响测量结果。为分析集中质量悬臂梁抗冲击能力,利用模态叠加法建立集中质量悬臂梁在冲击载荷作用下理论模型,分析集中质量悬臂梁在冲击载荷作用下动态响应及破坏规律。研究结果表明:集中质量悬臂梁固有频率越高,应力峰值越大,越容易发生塑性变形或断裂;对于集中质量悬臂梁,冲击载荷破坏能力仅与极限谱位移有关,极限谱位移越大,其破坏能力越大;负波延迟对集中质量悬臂梁的破坏能力具有一定影响,可在常规抗冲击设计中通过增大极限谱位移考虑此影响。     

多次水下爆炸钢制圆板应变与挠度增长规律分析

在海上战争中,水面舰艇以及潜艇可能会受到多枚水中兵器的攻击,产生的累计损伤问题影响着水面舰艇以及潜艇的持续作战能力和生命力。对膨胀直径为390 mm,厚度为5 mm空气背衬钢制圆板,在50 g药量下,进行持续多次水下爆炸加载试验,对板中心应变、挠度以及厚度减薄率进行测量,试验结果分析表明:第一次爆炸加载时,局部空化使钢板产生的应变是冲击波加载的1倍,当钢板被炸弯后,再次爆炸加载局部空化的二次加载现象不明显。此外,气泡脉动及气泡射流会使钢板发生明显的弹性应变,应变值是初始冲击波作用的10%。对中心挠度和厚度减薄率的数据分析发现,钢板厚度减薄率是随着中心挠度呈线性增加的。该研究对舰船持续作战能力及生命力的评估提供了一定的试验支撑。     

岩石中爆炸冲击波能量分布规律初探

本文就冲击波能量主要消耗在爆腔扩胀,形成裂隙和引起岩石弹性变形上讨论。首先分析了冲击波作用岩石变形和破坏的特点,在此基础上探讨了炮孔柱状装药爆破时冲击波能量的分布规律以及各部分能量消耗量的求算方法。     

Viscoplastic response of a circular plate to an underwater explosion shock

Summary Viscoplastic response of a fully-clamped circular plate to an underwater explosion shock is studied in this paper. Strain-rate effect is included in the response. A fluid-structure interaction model is introduced, which is characterized by two stages: In the early stage, only the shock wave in water is considered, and the motion of structure is neglected. In the second stage, the wave propagation in structure and fluid is disregarded, and only long-term fluid force (added mass) and long-term structural force (membrane stress) are considered. Based on this model, the equation of motion of a fully-clamped circular plate is established, the solutions of which are compared with two experiments. The calculated maximum plastic deformations from present model are close to the observed values. The dependence of maximum plastic deformation on charge weight, plate radius and material property is also discussed.     

等效靶弹药空气中爆炸威力评估

针对传统的冲击波压力电测法操作复杂且易受干扰的问题,提出基于等效靶塑性变形的炸药爆炸威力评估方法。首先进行小当量立姿等效靶板变形试验,并基于实验结果确定适用于有限元数值模拟的模型;其次,使用量纲分析方法简化等效靶变形的理论模型,建立靶板中心最终变形挠度与爆炸当量、爆炸距离的关系;进一步结合实验数据与数值模拟结果,得出通过靶板变形挠度反演爆炸当量的计算公式,提出采用系列等效靶变形数据进行爆炸当量反演的评估方法。通过小当量试验和大当量数值模拟算例对该方法进行验证,在等效靶变形数据足够多的情况下,可以将反演爆炸当量误差控制在15%以内,满足一般工程评估精度要求。     

近爆作用下钢筋混凝土π梁防护性能的数值模拟

为研究钢筋混凝土π截面梁在近场爆炸荷载作用下的防护方法,采用ANSYS/LS-DYNA建立π梁爆炸数值模型,结合现场爆炸试验结果,对π梁在爆炸荷载作用下的破坏形态进行对比分析,验证数值模型的准确性.通过π梁在近爆荷载下采用不同防护层进行模拟分析,对π梁在不同防护工况下冲击波超压峰值分布规律、结构耗能规律、防护后π梁的破...     

AN INVESTIGATION OF HIGH-SPEED FORMING OF CIRCULAR PLATES IN A LIQUID SHOCK TUBE

High-speed metal forming with liquid shock waves, generated non-explosively in a liquid shock tube, is a new field of study. The advantage of forming with liquid shock waves in a shock tube in comparison to explosive forming is better control and increased safety. This paper describes the experimental set-up of the liquid shock tube and presents the results of experiments performed with fully clamped circular copper disks subjected to the impulsive load of the liquid shock wave. The strain conditions of the deformed disks are determined and the deformation energy is calculated. A theoretical approach is also given to predict the midpoint deflection of the specimen. The experiments show a good repeatability and the calculated deformation energy and the predicted midpoint deflections reveal a good agreement with the experiments. The deformation process of the metal disks during the impact of the liquid shock wave is investigated with a high-speed video camera. From the experiments the local and the average deformation velocities and the strain rates are determined. The pictures of the deforming plate also reveal a plastic hinge, which was theoretically predicted in literature.     

冲击载荷作用下火工分离保护装置的建模与分析

为了模拟空间火工分离保护装置冲击载荷下的动力学特性,首先,建立了该保护装置的简化模型,计算得到火工分离体的初速度,推导了装置的冲击变形和变形能公式;保护装置分别采用2A12、TC4、蜂窝夹层材料,建立三种材料的多线性本构模型,采用显式动力学求解步分析其冲击响应特性,分析可知,蜂窝夹层材料具有最佳的能量吸收特性,2A12的能量吸收特性介于蜂窝夹层材料和TC4之间,其塑性变形量适中;应变能释放和冲击碰撞的耦合分析可知,应变能占比小,体现为振荡衰减的过程,结构的冲击响应特性主要由碰撞冲击导致;试验表明,该火工分离保护装置的瞬态动力学过程与分析一致,局部最大应力为302MPa,冲击响应谱最大值为3242g,满足有效载荷的可靠解锁分离要求。     

非接触爆炸冲击载荷对防盗门作用数值模拟研究

为实现反恐行动中非接触爆炸冲击波破门目标,针对金属防盗门实际条件建立数值仿真模型,重点研究了防盗门在非接触爆炸冲击载荷作用下塑性变形破坏过程及规律。结果表明：相同爆炸冲击载荷作用下,实际转动条件防盗门板塑性变形动力响应时间延长,最大变形量远大于四边固支条件下门板变形量;爆炸中心与防盗门距离过近,门板受爆炸产物和空气冲击波共同作用,只出现局部破坏,不能实现门板整体塑性变形;拟合了防盗门板在非接触爆炸冲击载荷作用下变形量计算式,可为反恐破门弹药设计提供依据。     

球形炸药设计及其水下爆炸冲击波特性

雷管等爆炸元件的爆炸能量分布通常并不均匀,在离心机中研究爆炸问题对爆源的尺寸和爆炸能量分布要求较高,爆炸能量不均匀对试验结果存在影响,不符合爆炸力学中的点源假定。采用黑索金炸药制作球形炸药,探讨了细径导爆索及无起爆药雷管作为起爆方式的适用性。最终确定微型导爆雷管中心起爆球形炸药的方式,并研究了其水下爆炸冲击波特性,峰值压力与比例距离近似成线性关系,冲击波压力波形可以较好地采用冲击波压力公式拟合。     

多次水下爆炸作用下钢板与焊接钢板冲击损伤特性

为了研究舰船结构在多次水下爆炸载荷作用下的抗爆抗冲击能力,基于水下爆炸鼓胀试验分别开展了5 mm、12 mm的船用A32背空钢板及焊接板的多次水下爆炸试验,得到了钢板与焊接板的塑性变形历程,测量并计算了钢板与焊接板受冲击区域沿半径各点处的挠度及厚度减薄率,分析了钢板与焊接板的塑性变形规律。结果表明:多次水下爆炸载荷作用下,焊接板与钢板的塑性变形形貌呈类球冠形,二者的厚度减薄率从中心位置到边界处呈先减小再增大的趋势,但焊接板的挠度小于钢板的挠度。A32钢板的变形模式主要为弯曲和拉伸变形,焊接板以弯曲变形为主。持续增加的水下爆炸载荷导致钢板中心位置与边界处拉伸断裂,而焊接板的焊缝及其热影响区发生脆性断裂。     

A study of explosive effects in close proximity to a submerged cylinder

Measurements of acceleration and pressure together with high-speed imaging have been used to study the interaction of an underwater explosion with a nearby steel cylinder. Variation of the initial separation between the cylinder and explosive charge generated different cases of interaction in which the response of the cylinder to the shock wave, the bubble pulse wave, water jetting and bubble collapse could be studied. Shock wave loading generated a significant response in all cases. The pressure wave from the pulsating bubble was a less significant load, generating a peak velocity about half that caused by the shock wave. However the collapse of the bubble onto the cylinder was found to be the most severe structural load, generating a peak velocity almost twice that caused by the shock wave and causing significant plastic deformation.     

EFFECT OF AN ELASTIC-PLASTIC SHOCK WAVE PART A: ON THE FATIGUE STRENGTH OF WELDED JOINTS

Fatigue data for welded joints subjected to an explosion treatment (ET) were obtained using rotary bending fatigue specimens. The fatigue fracture surfaces were observed by SEM and the dislocation morphologies by TEM. Mechanical properties have been quantitively studied by considering elastic and plastic shock wave characteristics. The test results indicate that the fatigue strength of welded joints subjected to ET is apparently improved due to the action of elastic or plastic stress waves while the ductility of the welded joints, i.e., reduction in area, is greatly increased.     

激光冲击2024 铝合金诱导动态应力应变实验研究

为了研究激光冲击波动态加载过程中金属材料的动态应力应变特性,采用高功率激光器单次冲击2024 铝合金薄板,利     

远场水下爆炸作用下舰船设备冲击响应一体化动力学模型

提出了一种远场水下爆炸作用下舰船设备冲击响应一体化动力学模型。该模型将动态设计分析方法(DDAM)与Taylor平板理论相结合,使得对舰船设备冲击响应分析更为高效。将船体外壳看做平板,将船体各层甲板和设备看做附加在平板上的多个质量,将水下爆炸冲击波看做指数衰减波,形成了一维分析模型。能够根据水下爆炸当量、爆距、舰艇吨位、总尺度、结构和设备质量与支撑刚度等参数预测舰船与设备的冲击响应。预测结果与舰船缩比模型水下爆炸试验结果进行了对比。从总体上看,船体冲击响应谱的趋势和量级一致。     

水胶炸药不同交联时间水下爆炸能量的研究

为了研究化学发泡剂对水胶炸药水下爆炸能量的影响,制备了交联时间分别为0.5、1.0、3.0、24.0、72.0 h和168.0 h的水胶炸药;在相同的试验条件下,采用水下爆炸法分别测试不同交联时间下水胶炸药水下爆炸的比冲击波能、比气泡能以及总能量,并与2^#岩石乳化炸药水下爆炸总能量进行对比。结果表明,化学发泡剂对水胶炸药水下爆炸能量有较大的影响,在一定的交联时间范围内,随着交联时间的延长,水胶炸药的水下爆炸能量持续增加,当交联时间为72.0 h左右时,水胶炸药的水下爆炸能量达到最大;此后,若再延长交联时间,水胶炸药的水下爆炸能量呈下降趋势。交联时间为1.0 h时,水胶炸药的水下爆炸总能量与2^#岩石乳化炸药的水下爆炸总能量相当。