铝合金三角形波纹夹芯板抗平头弹冲击的损伤特性研究

为研究铝合金三角形波纹夹芯板受到平头弹冲击后的损伤形式与抗冲击性能,利用一级气炮对铝合金三角形波纹夹芯板的两种冲击位置进行冲击试验。根据试验数据,对比分析三角形波纹夹芯板及等面密度单层板的弹道极限速度与耗能,并结合有限元仿真分析夹芯板的动态损伤过程、动态载荷响应及损伤机理。研究结果表明,三角形波纹夹芯板损伤形式为剪切破坏、撕裂破坏与弯曲变形。波纹板的抗冲击性能低于等面密度的单层板,并且波纹板节点位置的抗冲击性能高于基座位置。当弹体冲击速度较低时,波纹板的耗能低于单层板,随着冲击速度增加,波纹板节点位置的耗能高于单层板,基座位置的耗能与单层板相近。此外,波纹板的动态载荷响应与失效机理均受到冲击位置与弹体冲击速度的影响。     

弹体头部形状对碳纤维层合板抗冲击性能影响实验研究

为研究弹体头部形状对碳纤维层合板抗冲击性能的影响,利用一级气炮发射卵形头弹、半球形头弹和平头弹,对2 mm厚碳纤维层合板进行了冲击实验。利用公式拟合处理实验数据,揭示弹体头部形状对靶板弹道极限与能量吸收的影响,并且分析靶板冲击损伤形貌及机理特征。研究结果表明:平头弹弹道极限最高,半球形头弹次之,卵形头弹最低。弹体在低速度冲击时,弹体头部形状对靶板能量吸收率的影响更为显著。平头弹冲击时,靶板迎弹面受到均匀分布的环向剪切力,纤维同时被剪切,基体发生大面积剪切破坏。半球形头弹冲击时,靶板迎弹面受到非均匀分布的剪切力和挤压作用,纤维发生剪切断裂和拉伸断裂,基体发生剪切破坏和挤压破碎。卵形头弹冲击时,纤维发生单一的拉伸断裂,而基体则发生挤压破碎。弹体头部形状对靶板损伤的影响主要集中在迎弹面和中部纤维层。     

2A12铝合金薄板对卵形头弹抗冲击性能研究

利用轻气炮撞击实验研究卵形弹丸冲击总厚度相等的2A12铝合金单层板和双层板,分析靶板分层和板间间隙对靶板失效模式以及抗冲击性能的影响,通过高速相机图片获取弹体速度数据。实验结果表明,单层板的弹道极限高于双层板的弹道极限,包括间隙式和接触式,并且接触式双层板的弹道极限高于间隙式双层板。随着弹体初始速度增加,靶体结构对其抗侵彻性能的影响随之减小。此外,利用Abaqus软件建立了数值模拟模型对实验工况进行了计算,将数值模拟和实验结果进行了对比,两者之间存在较好的一致性,这也表明数值模拟能够有效地测靶体的弹道极限。     

Kevlar层合材料抗弹性能研究

以Kevlar纤维增强层合材料为对象,通过系列弹道冲击实验,研究了层合板的抗弹性能,着重分析了弹头、纤维铺设方式以及板厚等因素对靶板抗侵彻能力的影响,同时对靶板的破坏模式也作了必要的讨论。此外,还通过一种工程近似方法,分析了不同弹头弹丸的弹道极限速度,预测值与实验值具有良好的一致性。     

连续玄武岩纤维增强环氧树脂基复合材料抗冲击性能研究

制备了连续玄武岩纤维增强的环氧树脂基复合材料靶板,并进行了抗冲击性能测试,研究了影响其抗冲击性能的主要因素及抗冲击机理.结果表明,表面处理会使复合材料抗冲击性能下降;而降低织物面密度、提高纤维体积含量可以使复合材料抗冲击性能得到提高.复合材料靶板的主要能量吸收形式为靶板局部变形、分层和纤维拉伸、剪切断裂及纤维拔脱.     

水下冲击载荷下波纹夹层结构动态响应特性分析

为了探讨波纹芯层夹层结构在水下爆炸冲击波作用下的动态响应特性和抗冲击防护能力,首先基于非药式水下冲击波加载试验,结合显示动力学软件对水下结构抗冲击解耦算法的有效性进行了验证。进而利用该算法对波纹夹层板在水下冲击作用下的动态响应进行了研究,得到了波纹夹层结构气背面板塑性变形与冲击波强度间的关系,同时比较分析了波纹夹层板与格栅夹层板及单层板的抗冲击性能。研究结果表明:具有相同面密度的夹层板抗冲击能力高于单层板,其中波纹型夹层板的抗冲击防护能力优于格栅夹层板,抗冲击性能相对于单层板提高了82.45%。     

GCr15弹丸冲击不同厚度GH4169板的变形与破坏模式试验研究EI北大核心CSCD

为理解航空发动机包容机匣用镍基高温合金GH4169遭受高速冲击载荷时的动态力学特性,采用GCr15硬质合金弹丸,利用一级空气炮试验装置对不同厚度(2 mm、3 mm、5 mm、6 mm)的GH4169靶板进行了弹丸速度从96.7~314.2 m/s的弹道冲击试验,对冲击载荷作用下靶板的变形、破坏模式和失效机理进行了系统的试验研究。结果表明:在试验冲击速度范围之内,随着靶板厚度的增加,靶板的变形模式逐渐由拉伸与弯曲主导的蝶形变形转变为局部的剪切变形;同时靶板的破坏模式由花瓣形损伤与冲塞共存模式向单一剪切冲塞模式转变;随着冲击速度的增加,靶板对弹丸动能的吸收能量是逐渐增加的,但在临界穿透速度时出现一个拐点,使得靶板被击穿后吸收能能量的增速变缓,表明靶板被穿透破坏后降低其的吸能能力;当冲击速度为临界穿透速度时靶板变形挠度达到最大值;冲击后靶板的花瓣裂纹数量与弹体速度呈线性关系。当入射速度为284 m/s时,与试验结果比较,修正后R-I公式预测弹丸剩余速度比未修正的结果精度提高7.01%。     

基于内翻复合材料管的冲击吸能器特性研究

提出了一种利用复合材料管向内翻转、压溃来吸收冲击能量的吸能器。吸能器由复合材料管和两端的连接帽组成,其中一个连接帽内端面为平面;另外一个连接帽内端面为曲面,在复合材料管受到轴向冲击时,使管壁内翻,产生分层和断裂,并逐渐填满复合材料管内腔。在复合材料管的压溃过程中,没有任何的碎屑溢出,在管材内腔的碎屑逐渐被压实,进一步提高吸能器的性能。吸能器主要通过复合材料分层、断裂以及复合材料管与套筒间的摩擦来吸收冲击能量。分别使用静态试验和冲击试验研究了连接帽内表面曲率对吸能效果的影响,结果表明,该新型吸能器在减小初始峰值载荷的同时能够增加材料的比吸能,非常适合应用于轻量化的抗冲击结构中。     

复合材料弹道性能的实验与估算

通过玻璃纤维／双马树脂，芳纶／缩丁醛复合材料靶板的实弹实验，获得了不同面密度复合材料靶板的抗弹性能数据，在分析实验数据的基础上建立了复合材料靶板弹击后能量吸收Ｅｖ和弹道极限速度Ｖ５０的理论估算式，并求得单位面密度上的能量吸收值ＢＰＩ。文中所得结果对防弹复合材料的进一步研究和复合材料靶板设计有参考价值。     

纤维取向对TC4/PEEK/Cf层板抗高速冲击性能的影响

为研究高速冲击条件下TC4/PEEK/Cf层板破坏失效行为和机理,采用空气炮高速冲击试验探索了纤维取向对层板抗高速冲击性能的影响,并建立了误差有效控制的有限元模型。使用验证后的模型对不同变量下层板冲击试验进行算例丰富。试验和模拟结果表明：TC4/PEEK/Cf层板高速冲击下损伤模式主要是金属/复合材料界面分层、复合材料内部层间分层、金属塑性变形、复合材料撕裂断开等。通过对比不同纤维取向层板高速冲击破坏特征发现,TC4/PEEK/Cf层板抗高速冲击性能与纤维铺放角度有关。层板整体耗散冲击能量的性能随纤维交叉角度增大而提高,纤维单向铺放层板的弹道极限和能量耗散率最低,0°/90°纤维取向层板的弹道极限和能量耗散率最高,抗冲击性能最优。     

High velocity impact response of Kevlar-29/epoxy and 6061-T6 aluminum laminated panels

The high velocity impact response of composite laminated plates has been experimentally investigated using a nitrogen gas gun. Tests were undertaken on sandwich structures based on Kevlar-29 fiber/epoxy resin with different stacking sequence of 6061-T6 Al plates. Impact testing was conducted using cylindrical shape of 7.62 mm diameter steel projectile at a range of velocities (180–400 m/s) were investigated to achieve complete perforation of the target. The numerical parametric study of ballistic impact caused by same conditions in experimental work is undertaken to predict the ballistic limit velocity, energy absorbed by the target and comparison between simulation by using ANSYS Autodyn 3D v.12 software and experimental work and study the effects of shape of the projectile with different (4, 8 and 12 mm) thicknesses on ballistic limit velocity. The sequence of Al plate position (front, middle and back) inside laminate plates of composite specimen was also studied. The Al back stacking sequence plate for overall results obtained was the optimum structure to resist the impact loading.The results obtained hereby are in good agreement with the experimental (maximum error of 3.64%) data where it has been shown that these novel sandwich structures exhibit excellent energy absorbing characteristics under high velocity impact loading conditions. Hence it is considered suitable for applications of armor system.     

Ballistic Limit of Single and Layered Aluminium Plates

Abstract: This paper presents an experimental and finite‐element investigation of ballistic limit of thin single and layered aluminium target plates. Blunt‐, ogive‐ and hemispherical‐nosed steel projectiles of 19 mm diameter were impacted on single and layered aluminium target plates of thicknesses 0.5, 0.71, 1.0, 1.5, 2.0, 2.5 and 3 mm with the help of a pressure gun to obtain the ballistic limit in each case. The ballistic limit of target plate was found to be considerably affected by the projectile nose shape. Thin monolithic target plates as well as layered in‐contact plates offered lowest ballistic resistance against the impact of ogive‐nosed projectiles. Thicker monolithic plates on the other hand, offered lowest resistance against the impact of blunt‐nosed projectiles. The ballistic resistance of the layered targets decreased with increase in the number of layers for constant overall target thickness. Axi‐symmetric numerical simulations were performed with ABAQUS/Explicit to compare the numerical predictions with experiments. 3D numerical simulations were also performed for single plate of 1.0 mm thickness and two layered plate of 0.5 mm thickness impacted by blunt‐, ogive‐ and hemispherical‐nosed projectiles. Good agreement was found between the numerical simulations and experiments. 3D numerical simulations accurately predicted the failure mode of target plates.     

Q235钢单层板对平头刚性弹抗穿甲特性研究

采用撞击实验和理论模型对单层金属板的抗侵彻性能进行了研究,分析了靶体厚度对抗侵彻性能的影响。通过对比撞击实验和理论模型计算结果,验证了理论模型和参数的有效性。结果表明,采用合适的理论模型能够有效地预测靶板在弹体撞击下的弹道极限。此外,分析了靶体在弹体撞击下的塑性变形总耗能,包括靶板局部变形和整体变形的耗能,同时考虑了靶体材料的应变率效应。在平头弹撞击厚靶的工况中,引入了一个修正函数对靶体厚度进行修正。     

Effect of projectile nose shape,impact velocity and target thickness on the deformation behavior of layered plates

The present study is based on the experimental and numerical investigations of deformation behavior of layered aluminum plates of different thicknesses under the impact of flat, ogive and hemispherical nosed steel projectiles. Thin-layered plates arranged in various combinations were normally impacted at different velocities with the help of a pneumatic gun. Ballistic limit velocity and the residual velocity of the projectiles for each layered combination were obtained experimentally as well as from the finite element code, and these were compared with those of the single plates of equivalent thicknesses. For two layers, the residual velocity was comparable to that of the single plate, however, when the number of layers was increased the velocity drop was found to be higher in the case of the single plate. Ogive nosed projectile was found to be the most efficient penetrator of the layered target. Hemispherical nosed projectile required maximum energy for perforation. Deformation profiles of the target plates in the layered combinations were measured, and it was found that hemispherical nosed projectile caused highest plastic deformation of target plates. Numerical simulation of the problem was carried out using finite element code ABAQUS. Explicit solution technique of the code was used to analyze the perforation phenomenon. Results of the finite element analysis were compared with experiments and a good agreement between the two was found.     

The effect of impact velocity and target thickness on ballistic performance of layered plates using Taguchi method

This paper presents the effect of test parameters such as Impact velocity, configuration and target thickness on ballistic performance of weldox steel plates against 7.62 mm APM2 projectile using Taguchi method. Trials were planned using an L 18 orthogonal array with 18 combinations of test variables to assess the influence of various factors. Numerical simulations have been carried out using Ansys Autodyn code with the above three process variables. Failure mechanisms of target plates of various single and multi-layered configurations were also discussed. Most portion of the kinetic energy of the projectile was expended in plastic deformation of the target material before perforation due to better bending stiffness of the target plate. Results showed that target thickness and impact velocity were the significant variables on residual velocity. Layer configuration was found to be insignificant relating to ballistic performance. Significant interaction is observed between impact velocity and target thickness from interaction plots. Simulated and experimental results showed good agreement with each other.     

Behavior of E-glass composite laminates under ballistic impact

The use of light weight armor against ballistic threats is very important for increasing mobility and survivability. This paper describes ballistic performance of an E-glass/phenolic composite as a function of laminate thickness and projectile impact velocity using mild steel core projectile. The results show that there is a nonlinear relationship between the energy absorption and laminate thickness. The effect of thickness and velocity on energy absorption in the laminates has been explained in terms of interaction time between target and projectile. It is also observed that deformation of the projectile is more dependent on the target thickness than the strike velocity. Changes in failure mechanisms with change in target thickness are also described.     

玻璃纤维-不锈钢网混杂增强环氧树脂层合板对球形弹斜冲击响应特性实验研究

为了研究玻璃纤维-不锈钢网混杂增强环氧树脂层合板在球形弹高速斜冲击下的损伤特性,利用一级气炮对2 mm厚度的玻璃纤维增强环氧树脂复合材料层合板和含一层、三层304不锈钢网的玻璃纤维-不锈钢网混杂增强环氧树脂层合板进行倾角为30°的冲击实验,以揭示304不锈钢网对层合板弹道极限和能量吸收的影响规律,并分析层合板损伤特征及其机理。通过实验发现,含有三层不锈钢网层合板的弹道极限最高,而不含不锈钢网层合板和含一层不锈钢网层合板的弹道极限速度接近。层合板吸收的能量随着弹体速度增加呈现出先增加后趋于平稳,然后急剧上升的趋势。层合板损伤模式为基体开裂和破碎、分层、不锈钢丝拉伸断裂、纤维拉伸断裂和剪切断裂。层合板分层损伤面积随弹体速度增大先增大后减小,最后趋于稳定。当弹体速度较低时,层合板主要发生纤维拉伸断裂、基体开裂、层间有分层损伤产生。随着弹体速度的增大,层合板正面纤维逐渐发生压剪断裂、基体破碎,背面纤维发生严重的拉伸撕裂。      

TC4钛合金板厚度对其撞击失效特性影响研究

为了揭示TC4钛合金板抗撞击性能与失效模式随厚度的变化规律及机理,采用ABAQUS/Explicit有限元软件建立平头弹撞击不同厚度靶板的模型,对弹体撞击不同厚度靶板进行计算。通过对比数值仿真与撞击实验结果,验证仿真模型的有效性。研究结果表明,靶板的主要失效模式、耗能机制、弹道极限随其厚度增加会发生改变,靶板厚度存在对应的转折值。对于TC4钛合金薄板,当靶板厚度比较小时,靶板拉伸撕裂破坏占主导作用。但是,当靶板厚度比较大时,靶板主要失效模式是局部剪切破坏。当靶板厚度小于4 mm、大于8 mm时,弹道极限速度随靶板厚度的增加而增加;当厚度为4~8 mm时,弹道极速度变化不明显。     

Woven glass/epoxy laminates subject to projectile impact

Impact results of woven E-glass/epoxy composite laminates are presented in this paper. A gas gun was employed to launch 12.7 mm diameter hemispherically-tipped projectiles 35.5 g in weight. The developed laser Doppler anemometer (LDA) system was successfully employed to record the projectile velocity history, whose range was from several m/s to twice the ballistic limit of the target, and was converted into the force history by using both the optimization and the polynomial curve-fitting methods. It was found that, when the projectile initial velocity was lower than the ballistic limit, the delamination area was approximately proportional to the initial energy of the projectile, and the relationship between the absorbed energy and initial energy of the projectile followed a straight line of unit slope when it was expressed non-dimensionally. Also, the incremental rate of the peak impact force became gradually smaller and finally reached a constant value at the ballistic limit, and the impact force history became progessively asymmetric. Beyond the ballistic limit, the absorbed energy remained approximately constant regardless of the increase of the initial striking velocity of the projectile. The peak impact force, on the other hand, was surprisingly found to increase again.     

Ballistic limit for oblique impact of thin sandwich panels and spaced plates

Ballistic perforations of monolithic steel sheets, two-layered sheets and lightweight sandwich panels were investigated both experimentally and numerically. The experiments were performed using a short cylindrical projectile with either a flat or hemispherical nose that struck the target plate at an angle of obliquity. A total of 170 tests were performed at angles of obliquity 0–45°. The results suggest that during perforation by a flat-nosed projectile, layered plates cause more energy loss than monolithic plates of the same material and total thickness. There was no significant difference in the measured ballistic limit speed between monolithic plates and layered plates during oblique impact perforation by a hemispherical-nosed projectile.