陶瓷/纤维复合装甲抗弹丸侵彻性能的试验与数值模拟研究

本工作研究了由碳化硼(B4C)/碳纤维(CF)/超高分子量聚乙烯纤维(UHMWPE)组成的复合装甲对抗7.62 mm穿甲燃烧弹的抗侵彻性能.通过实验和数值模拟,系统地研究了陶瓷复合装甲各层对弹丸的作用机理.首先将模拟与实验结果进行比较,验证了模拟方法的可靠性.在此基础上,开展了陶瓷复合装甲的陶瓷面板的材料/厚度数值模拟研究,分别采用氧化铝(Al2 O3)、碳化硅(SiC)、碳化硼(B4 C)作为陶瓷面板,研究了不同厚度陶瓷板的吸能效率,结果表明,以B4 C陶瓷作为面板,当其厚度为10 mm时所得复合装甲的防弹性能最佳.     

蜂窝点阵-陶瓷复合装甲在联合载荷下的动态力学行为EI北大核心CSCD

为了探究具备抗多发弹打击的蜂窝点阵-陶瓷复合装甲在冲击波与破片联合载荷下的防护性能,改善当前防护装甲基于破片或爆炸冲击波单一载荷开展结构设计的不足。通过泡沫铝-弹丸复合弹模拟联合载荷,采用有限元模拟,研究蜂窝点阵-陶瓷复合装甲在联合载荷作用下的结构动态响应与毁伤机理,明确速度差和预变形两种协同作用机制;进一步研究联合载荷中爆炸冲击波与破片抵达先后顺序与抵达时间差对复合装甲防护性能的影响。最终,进行参数化研究,讨论蜂窝点阵-陶瓷复合装甲中,不同子结构关键几何参数对防护性能的影响规律,评估不同子结构的防护贡献,为最优防护性能设计提供指导。     

陶瓷复合装甲优化设计及弹击后剩余弯曲强度

根据防护要求和防护机制,设计了一种C/C-SiC陶瓷/铝基复合泡沫复合装甲。在确保复合装甲面密度为44 kg/m²的前提下,以弹击后剩余弯曲强度为评价标准,以陶瓷板布置位置、各组成层厚度、泡沫金属中泡沫孔径尺寸为研究因素,设计了三因素三水平的正交模拟优化方案,利用有限元软件ABAQUS模拟了子弹侵彻陶瓷靶板的过程及弹击损伤后复合装甲的弯曲实验过程,预测了剩余弯曲强度,并进行了结构优化。根据数值模拟结果制备陶瓷复合装甲试样,进行实弹打靶和弯曲实验以验证复合装甲试样剩余弯曲强度。结果表明,以MIL-A-46103E Ⅲ类2A级为防护标准,剩余弯曲强度最高的陶瓷复合装甲最优化结构形式为：陶瓷板厚度12 mm、陶瓷板做防弹面板、Al基复合泡沫孔径为4 mm+10 mm的混合;对剩余弯曲强度的主次影响因素排序为：陶瓷板厚度>陶瓷板布置位置>Al基复合泡沫孔径。     

黏结层对陶瓷/金属复合装甲抗弹性能的影响研究

采用二级轻气炮加载装置和AUTODYN软件对含环氧树脂黏结层的陶瓷/金属复合装甲的抗弹性能展开了研究。陶瓷面板分为叠层和单层板两种形式,对应于C/E/A(Ceramic/Epoxy resin/Aluminum alloy)和C/E/C/E/A(Ceramic/Epoxy resin/Ceramic/Epoxy resin/Aluminum alloy)复合装甲。结果表明,受应力波传播和破碎锥作用,C/E/C/E/A装甲较C/E/A装甲的陶瓷面板破碎程度更大。具有缓冲作用的黏结层,随其厚度的增加,陶瓷损伤程度逐渐减小,背板侵深也逐渐减小。对Yaziv系数的修订表明,在相同弹速和黏结层厚度条件下,相同面密度的叠层陶瓷装甲抗弹性能优于单层陶瓷装甲。但是,黏结层厚度的增加对C/E/C/E/A装甲的抗弹性能贡献不大,而对C/E/A复合装甲的影响却较大。最后,对于两种形式陶瓷复合装甲,黏结层均使得装甲内透射应力波幅值得到了有效衰减,尤其是C/E/C/E/A装甲。     

多层异质复合结构的动力学响应及抗侵彻性能

为研究多层异质复合结构动力学响应及抗侵彻性能,利用霍普金森试验装置,对不同材料排布顺序及含泡沫铝夹芯的多层复合结构进行冲击加载,通过贴在入射杆和透射杆上的应变片测得入射波、反射波、透射波波形,验证数值仿真模型正确性;结合数值模拟,研究不同结构对试件内部应力波传播特性和应力场分布影响规律;依据复合结构动力学响应特征,设计复合靶板并进行抗侵彻试验,分析靶板塑性变形特征及抗侵彻耗能机制;通过数值模拟分析泡沫铝夹芯厚度对防护性能影响。结果表明,装甲钢后置复合结构及含泡沫夹芯结构有助于减缓应力集中,减小陶瓷损伤面积;泡沫铝夹芯过厚难以为靶板变形提供支撑,降低抗侵彻阻力;五种夹芯厚度h=2 mm、h=5 mm、h=10 mm、h=20 mm、h=30 mm中,h=10 mm对应多层异质复合靶防护性能最优。      

仿生鳞片式拼接柔性防护结构防弹性能研究

目的 根据仿生学原理,借鉴鳞甲类生物柔性拼接模式,设计出由碳化硼陶瓷和超高分子量聚乙烯(UHMWPE,PE)背板复合而成的仿生鳞片式拼接柔性防护结构,以提高防护装备的灵活性和抗多发弹性能。方法 首先通过高温热压成形工艺制备出复合鳞片,然后采用95式5.8 mm钢芯弹进行侵彻试验,最后结合有限元仿真对侵彻过程中的弹击损伤机制和能量耗散形式进行分析。结果 弹丸侵彻导致复合鳞片的陶瓷层发生了严重的碎裂现象,PE背板发生了类圆状凹陷变形,但未被穿透;单次弹击损伤范围被限制在弹击鳞片及其相邻鳞片附近,未形成大面积损伤,表现出优异的抗多发弹性能;弹丸的能量通过弹击鳞片扩散到与其相邻的鳞片上,降低了弹丸对弹击鳞片的损伤,提高了柔性结构的极限抗单发弹性能。结论 仿生鳞片式拼接柔性结构能够有效抵御95式5.8 mm钢芯弹的侵彻,具备柔性的同时还具有优异的抗多发弹性能,可应用于新一代单兵及武器装备的小口径枪弹防护装甲。     

SiCP/Al功能梯度装甲板抗侵彻性能的试验与数值模拟

采用粉末冶金方法制备碳化硅陶瓷颗粒(SiC_P)增强金属铝基复合材料板(MMCs), 并采用热压扩散法制备功能梯度装甲板(FGM)。利用高速冲击空气炮系统, 对纯铝靶板和两种不同铺层结构的功能梯度装甲靶板进行侵彻试验, 并利用LS-DYNA软件对侵彻试验过程进行数值模拟分析, 同时考察等厚、 等面密度下SiC颗粒分布对抗侵彻性能的影响。研究结果表明, 功能梯度板的抗侵彻性能比纯铝板好, 而两种不同铺层结构功能梯度板的抗侵彻性能相差不大。数值计算结果与现有试验结果取得了较好的一致, 说明了数值模拟的有效性。从数值计算结果可以看出, 层状功能梯度板比等厚、 等面密度均质复合材料靶板的抗侵彻能力好, 并可近似地认为等厚、 等面密度下多层功能梯度板的抗侵彻性能对颗粒分布不敏感。     

陶瓷/纤维/阻尼复合靶板抗冲击性能及优化

随着弹体的侵彻能力逐渐增强，复合防弹装甲成为不可或缺的装备之一。基于ANSYS建立了陶瓷/纤维/阻尼复合防弹靶板的冲击有限元模型，揭示了材料参数和几何参数对复合防弹靶板的影响规律，利用多目标遗传算法优化了碳化硅陶瓷/碳纤维/超高分子量聚乙烯纤维/背层阻尼复合防弹靶板结构，并通过实验验证了优化设计结果的可信性。结果表明：同面密度条件下，涂刷一定厚度背层阻尼对靶板防弹性能的提升较为显著；采用遗传算法优化后的复合防弹靶板结构为：6.9mm碳化硅陶瓷/4.8mm碳纤维层合板/6.0mm超高分子量聚乙烯(UHMWPE)纤维层合板/1.1mm阻尼，面密度为36.236kg/m²。相同防弹性能条件下，与陶瓷/装甲钢结构靶板相比，优化后的靶板面密度降低超过49%。     

影响陶瓷装甲抗弹性能的主要因素

根据陶瓷复合装甲的抗弹原理,综述了陶瓷材料性能、陶瓷面板的形状和尺寸、陶瓷装甲的结构形式等主要因素对陶瓷装甲抗弹性能的影响,通过对这些因素的提高和优化来提高装甲的抗弹性能。     

基于犰狳外壳仿生的SiC-超高分子量聚乙烯柔性防护板的试验测试和有限元模拟

个体防护装甲的发展对提高单兵作战能力具有重要意义,基于仿生研究可以为设计高性能装甲提供新的思路。犰狳外壳由六边形鳞片紧密拼接而成,采用分层结构设计,具有很好的柔性和防护能力。本文借鉴犰狳外壳的几何排列模式,采用SiC陶瓷片模仿硬质壳层,超高分子量聚乙烯(UHMWPE)热压板模仿软质壳层,按1∶1厚度比例设计制备仿生复合鳞片,将仿生鳞片紧密排列后封装制成一种新型柔性复合防弹插板。为了验证该种防弹插板的防弹性能并研究其破坏特征,进行弹道极限V0试验测试,结合有限元模拟分析其抗7.62 mm手枪弹侵彻的能力。结果表明:该柔性防弹插板不仅满足防弹性能要求,且具备较好的柔性,可为今后新型防弹插板的设计和优化提供参考。      

复合装甲中吸波层对材料防弹性能的影响

冲击波对复合装甲的破坏程度和方式受到一些因素的影响。采用吸波层来减弱冲击波对材料本身的破坏程度,初步研究了冲击波破坏装甲的形式和机理,并从防止冲击波振荡叠加的角度提出一些提高复合装甲防弹性能的措施。试验结果表明,使用吸波层使复合装甲的防弹性能有了明显的提高。     

陶瓷-金属复合材料在防弹领域的应用研究

陶瓷-金属复合材料具备高硬度、高强度、高韧性以及低密度的优点,已被广泛应用于防弹领域.介绍了几种陶瓷-金属复合装甲形式及其相应特点,重点论述了陶瓷-金属功能梯度装甲的研究进展,并对其前景和当前的工作重点进行了讨论.     

The effect of hybridization on the ballistic impact behavior of hybrid composite armors

In the present study, effect of hybridization on the hybrid composite armors under ballistic impact is investigated using hydrocode simulations. The hybrid composite armor is constructed using various combinations and stacking sequences of fiber reinforced composites having woven form of fibers specifically high specific-modulus/high specific-strength Kevlar fiber (KF), tough, high strain-to-failure fiber Glass fiber (GF) and high strength/high stiffness Carbon fiber (CF). Different combinations of composite armors studied are KF layer in GF laminate, GF layer in KF laminate, KF layer in CF laminate and CF layer in KF laminate at various positions of hybridized layers for a fixed thickness of the target. In this article the results obtained from the finite element model are validated for the case of KF layer in a GF laminate with experimental predictions reported in the literature in terms of energy absorption and residual velocity and good agreement is observed. Further, the effect of stacking sequence, projectile geometry and target thickness on the ballistic limit velocity, energy absorbed by the target and the residual velocity are presented for different combinations of hybrid composite armors. The simulations show that, at a fixed thickness of the hybrid composite armor, stacking sequence of hybridized layer shows significant effect on the ballistic performance. The results also indicate energy absorption and ballistic limit velocity are sensitive to projectile geometry. Specifically, it is found that arranging the KF layer at the rear side, GF layer in the exterior and CF layer on the front side offers good ballistic impact resistance. The hybrid composite armor consisting of a CF layer in KF laminate acquires maximum impact resistance and is the best choice for the design compared to that of other combinations studied.     

Experimental investigation of impact on composite laminates with protective layers

This paper presents an experimental study of low energy impacts on composite plates covered with a protective layer. In service, composite materials are subjected to low energy impacts. Such impacts can generate damage in the material that results in significant reduction in material strength. In order to reduce the damage severity, one solution is to add a mechanical protection on composite structures. The protection layer is made up of a low density energy absorbent material (hollow spheres) of a certain thickness and a thin layer of composite laminate (Kevlar). Energy absorption ability of these protective layers can be deduced from the load/displacement impact curves. First, two configurations of protection are tested on an aluminium plate in order to identify their performance against impact, then the same are tested on composite plates. Test results from force–displacement curves and C-scan control are compared and discussed and finally a comparison of impact on composite plates with and without protection is made for different configurations.     

Ballistic Penetration of Dyneema Fiber Laminate

UHMWPE fiber (Dyneema) reinforced composites are an important class of materials for armors.These materials provide superior ballistic performance to the armor, such as the military armor systems requiring a reduction in back-armor effects or a substrate for hardened facings of steet or ceramic. The reported work characterized the ballistic impact and mechanical performance of Dyneema fiber in composite laminates. The capability of the laminate to absorb ballistic impact energy was influenced by the impact velocity and the laminate areal density. Two kinds of penetration were compared and a two-step model for the penetration was proposed.     

Effects of composite adherend properties on stresses in double lap bonded joints

The effects of composite layer stiffness, thickness and ply orientations on stresses in the adhesive layer of a double lap bonded joint are investigated using three-dimensional finite element analysis code ABAQUS. A special 3-layer modelling technique is used in the finite element analysis. The non-linear behaviour of adhesive is also considered. Six composite laminates with different ply orientations are used in the lap-joint analysis. The composite materials considered in the analysis are – carbon epoxy, boron epoxy, T300/934 graphite-epoxy, and aramid epoxy. The analysis results indicate that the maximum stress in the adhesive can be significantly reduced by changing the stiffness and fibre orientations in the composite layer. Also, the use of hybrid composite (changing the nature of the fibres in two layers which are near the adhesive layer) results in reducing adhesive shear stresses.     

Modeling of the ballistic behavior of gradient design composite armors

The application of gradient design concept in armors offers possibilities in the reduction of weight and cost without significant reduction of ballistic resistance. Experimental results of composite backed plates consisting of layers of ceramic spheres embedded in epoxy showed that a ballistic limit of 3000 ft/s (1000 m/s) can be achieved, as shown in Fig. 1, without weight penalty compared to solid ceramic tiles. The ceramic sphere facing also provides the feasibility for flexible armor manufacturing. The design of such materials includes a plethora of parameters. In order to develop a precise methodology for the optimization of gradient design composite armors, an improved understanding of the relative significance of the design parameters must be developed. One way to study the relative significance of these parameters is through computational modeling. Computational limitations impose compromises in the modeling of both geometry and material behavior. Two types of models are discussed: (a) an approximate fiber/epoxy two-phase model for the backing; and (b) a damage-based, rate-dependent model for the ceramic spheres embedded in the epoxy. The development of a library of fiber architectures based on the unit cell has been initiated, which will open the possibility of the structural optimization along with simulation of the high velocity impact phenomena of advanced composites.     

Ballistic impact response of laminated hybrid materials made of 5086-H32 aluminum alloy,epoxy and Kevlar® fabrics impregnated with shear thickening fluid

The ballistic impact behavior of hybrid composite laminates synthesized for armor protection was investigated. The hybrid materials, which consist of layers of aluminum 5086-H32 alloy, Kevlar® 49 fibers impregnated with shear thickening fluid (STF) and epoxy resin were produced in different configurations using hand lay-up technique. The hybrid materials were impacted by projectiles (ammunitions of 150 g power-point) fired from a rifle Remington 7600 caliber 270 Winchester to strike the target at an average impact velocity and impact energy of 871 m/s and 3687 J, respectively. The roles of the various components of the hybrid materials in resisting projectile penetration were evaluated in order to determine their effects on the overall ballistic performance of the hybrid laminates. The effects of hybrid material configuration on energy dissipation during ballistic impacts were investigated in order to determine a configuration with high performance for application as protective armor. The energy dissipation capability of the hybrid composite targets was compared with the initial impact energy of low caliber weapons (according to NATO standards) in order to determinate the protection level achieved by the developed hybrid laminates. Deformation analysis and penetration behavior of the targets were studied in different stages; the initial (on target front faces), intermediate (cross-section), and final stages (target rear layers). The influence of target thickness on the ballistic impact response of the laminates were analyzed. Differences in ballistic behavior were observed for samples containing Kevlar® impregnated with STF and those containing no STF. Finally, mechanisms of failure were investigated using scanning electron microscopic examination of the perforations.     

Untersuchungen zum Erosionsschutz kohlenstoffaserverstärkter Duroplaste

Investigations on erosion protection of carbon-fibre-reinforced thermosetting plastics A double layer system of polyurethane rubber and a metal foil was described by calculation and experiment. There is a significant increase in erosion resistance of a carbon-fibre-reinforced plastic component by application of this system and the experimental results correlate with theoretical estimations. Among the investigated materials surface layers of titanium and a titanium aluminium alloy respectively possess the best resistance in the range of all angles of incidence. The polyurethane rubber also exhibits a very good erosion behaviour under conditions of normal impact as well as at shallow impact angles at room temperature. So the rubber takes care of a good emergency running quality after a destruction of the metal foil. It was found that the relative erosion rate of the protective metal layer decreases with increasing thickness of the rubber. A thickness of about 0,5–0,7 mm of the protective metal layer is sufficient in practice. The titanium foil should have a thickness of about 100–200 m?m for the design life because if the metal foil is too weak it will undergo destruction rather fast under laboratory conditions. There is no change of the well-known erosion mechanisms with the formation of walls around the places of normal impacts as well as grooving and machining at shallow impact angles by application of the double layer system. An increase in temparature up to 80 °C doesn't cause any change of the erosion rate of the investigated metal foils in the double layer system but will influence the erosion of the polyurethane rubber alone. The galvanic deposition of nickel is another way for the use of the double layer system especially for components with a complex geometric shape.