夹芯式复合结构抗高速破片侵彻性能试验

为抵御反舰导弹产生的高速破片,设计制作了以高强玻璃纤维板为面板、聚氯乙烯(PVC)泡沫材料和高强聚乙烯纤维板为芯层的复合结构,并开展弹道试验研究其抗侵彻性能,为对比分析开展了945钢抗高速破片侵彻试验。结果表明,前置高强玻璃纤维板产生纤维剪切、拉伸断裂、基体碎裂和纤维脱粘破坏,前置PVC泡沫产生压实坍塌、胞壁剪切断裂和压碎破坏,高强聚乙烯纤维板主要产生纤维剪切、拉伸断裂并出现背凸大变形,后置PVC泡沫板产生压实破坏,后置高强玻纤板并未明显破坏裂纹;立方体弹侵彻945钢板时产生严重墩粗变形,钢板产生剪切冲塞破坏;复合结构单位面密度吸能较945钢板提高34%。     

三维正交机织复合材料弹道冲击实验及破坏模式

本文用钢芯弹对三维机织复合材料作弹道冲击测试。得到了弹体的入射速度和剩余速度,比较了常见几种材料的弹道性能评价参数的差异,并考察侵彻破坏模式和靶体最后的损伤破坏形态。在300-800m/s冲击速度范围下观测了材料的冲击破坏形态,发现机织复合材料受弹面和子弹出射面破坏形态不一样,受弹面主要是以纤维的压缩、剪切破坏以及基体开裂为主,出射面以纤维的拉伸、厚度方向的纱线断裂为主要破坏模式。通过对破坏模式和形态的分析,可以帮助建立更加准确的破坏准则,从而在设计抗弹材料时起到一定的作用。     

双轴向经编针织复合材料的弹道侵彻破坏

通过真空辅助树脂传递模压法（VARTM）制造双轴向经编针织复合材料。在350～750m/s冲击速度范围内对复合材料作弹道冲击测试,得到弹体的入射速度、剩余速度及动能损失,弹体的剩余速度与入射速发近似满足线性关系,动能损失随弹速的增加呈现先上升后下降的状态。考察复合材料靶体的弹道侵彻破坏损伤形态,发现复合材料受弹面的破坏区域较子弹出射面的破坏区域小且破坏形态不同,由此揭示双轴向经编针织复合材料的弹道侵彻破坏模式与机理。     

三维正交机织复合材料弹道侵彻有限元模拟

测试复合材料弹道侵彻性质,得到复合材料弹道侵彻过程中子弹的入射速度和剩余速度及冲击破坏形态。基于复合材料的真实细观结构,建立细观结构模型,运用商用有限元软件ABAQUS/Explicit计算复合材料弹道侵彻破坏过程。研究发现三维正交复合材料不同破坏机制:三维正交机织复合材料不产生冲击分层,纤维断裂和基体开裂是主要吸能模式,复合材料冲击破坏是最主要的破坏模式。     

陶瓷/UHMWPE层合板/阻尼材料复合靶板防弹性能研究

提出一种由碳化硼陶瓷、UHMWPE层合板、阻尼材料构成的复合靶板。应用LS-DYNA动力学软件进行数值仿真分析,研究该靶板在12.7 mm穿甲爆炸燃烧弹高速冲击下的性能,并通过实验对数值模拟进行可行性验证。进一步研究靶板抗侵彻性能随结构几何参数变化的关系,探究阻尼材料的最佳分布位置和最佳厚度。结果表明:随着陶瓷厚度增大,靶板吸收子弹动能和弹道性能指数呈线性增加;在UHMWPE层合板厚度较大时,增加其厚度对靶板抗侵彻性能的提升更明显;同等面密度条件下,与提高陶瓷或者UHMWPE层合板的厚度相比,涂刷1 mm背层阻尼材料时,复合靶板弹道性能指数最高,抗高速侵彻性能最好,为阻尼材料作为减震层在抗高速冲击领域的广泛应用奠定了基础。     

基于功能梯度原理的超高性能混凝土抗侵彻爆炸性能

研究了单层结构和功能梯度结构的超高性能混凝土(UHPC)的抗侵彻爆炸性能。制备了3种靶体:普通混凝土靶,超高性能混凝土靶,以及不同种类UHPC组合而成的功能梯度混凝土靶(FGCC),并对不同种类混凝土靶体进行了侵彻爆炸实验,利用AUTODYN有限元软件进行了数值模拟分析。结果表明:从破坏形态上看,在侵彻爆炸耦合破坏下,FGCC靶破坏深度最小,弹坑深度不超过抗钻层范围。从损伤分布上看,混凝土损伤主要集中在迎弹面以及弹孔通道周围并向背弹面延对角线方向传递,纤维增强的靶体保持较好的完整性。从能量角度看,抗钻层高强粗骨料吸收子弹动能的能力强于混凝土基体。综合实验和数值模拟证明了功能梯度结构的UHPC具有优异的抗侵彻爆炸能力。     

基于功能梯度原理的超高性能混凝土抗侵彻爆炸性能EI北大核心CSCD

研究了单层结构和功能梯度结构的超高性能混凝土(UHPC)的抗侵彻爆炸性能。制备了3种靶体:普通混凝土靶,超高性能混凝土靶,以及不同种类UHPC组合而成的功能梯度混凝土靶(FGCC),并对不同种类混凝土靶体进行了侵彻爆炸实验,利用AUTODYN有限元软件进行了数值模拟分析。结果表明:从破坏形态上看,在侵彻爆炸耦合破坏下,FGCC靶破坏深度最小,弹坑深度不超过抗钻层范围。从损伤分布上看,混凝土损伤主要集中在迎弹面以及弹孔通道周围并向背弹面延对角线方向传递,纤维增强的靶体保持较好的完整性。从能量角度看,抗钻层高强粗骨料吸收子弹动能的能力强于混凝土基体。综合实验和数值模拟证明了功能梯度结构的UHPC具有优异的抗侵彻爆炸能力。     

含能破片冲击薄靶的释能时间

为了解释含能破片冲击侵彻薄靶板时的释能时间与侵彻历程关系,用LS-DYNA和理论分析研究了不同靶板材料、不同头部厚度的含能破片冲击侵彻过程和释能时间,得到释能时间与侵彻过程的关系.结果表明,通过调整破片的头部厚度可实现含能破片的靶后释能.     

高性能钢纤维增强混凝土的抗侵彻行为及数值模拟(英文)

采用大掺量超细工业废渣取代水泥,并掺加了天然河砂以及高弹、高强的玄武岩石子,制备了不同强度等级的高性能钢纤维增强混凝土材料。采用φ25mm弹道炮开展了初速度为500～850m/s的正侵彻实验,获得了弹丸着靶速度、最大侵彻深度、弹坑直径以及靶体破坏形态等实验参数,采用经典公式对侵彻深度进行了分析,同时采用非线性有限元方法对侵彻全过程进行了数值模拟。结果表明:侵彻深度随着材料强度等级的提高略有降低,粗集料的掺加有利于提高靶体的抗侵彻能力,随着纤维掺量的降低以及侵彻速度的提高,材料破坏程度明显加剧,数值模拟结果同试验结果吻合较好,侵彻深度的模拟结果与试验值的误差均在5%以内。     

子弹斜侵彻阻尼复合装甲的数值模拟

为了研究复合材料阻尼结构的抗冲击性能,利用ANSYS/LS-DYNA有限元软件模拟了12.7 mm的穿甲燃烧弹弹芯侵彻氧化铝/阻尼层/超高分子量聚乙烯(UHMWPE)复合装甲的过程,分别计算了钨合金弹芯以不同角度及不同速度侵彻靶板时的吸收能量情况,并探究了不同位置阻尼层厚度对复合装甲吸能效果的影响。计算结果表明,随着复合装甲靶板斜置角度的增加,靶板吸收的能量逐渐增加。通过模拟不同速度的钨合金弹弹芯斜侵彻复合装甲的过程,发现在700 m/s～850 m/s速度范围内复合装甲展现出最佳的吸能效果,且在复合装甲中不同位置的阻尼层达到最佳吸能效果的厚度不同。本工作可为后续研究阻尼复合结构的抗中高速冲击性能提供参考。     

聚脲弹性体/纤维增强树脂基复合材料抗冲击性能研究

玻璃纤维增强树脂基复合材料在使用过程中极易受到外力冲击,造成复合材料结构破坏,严重威胁其安全使用寿命。研究了聚脲弹性体涂层对玻璃纤维增强乙烯基树脂复合材料抗冲击性能的影响。通过简支梁摆锤冲击试验和光学显微镜对前涂覆(FCGF)、后涂覆(BCGF)及未涂覆(NCGF)试样进行对比测试。研究结果表明,聚脲弹性体涂层的弹性形变和断裂破坏能够大幅增加冲击能耗,提高整体的冲击强度。当试样聚脲涂层厚度相同时,前涂覆(FCGF)试样聚脲弹性体冲击后并未完全断裂,主要依靠弹性形变吸收冲击能量,起缓冲减震作用;后涂覆(BCGF)试样聚脲弹性体发生断裂破坏能够消耗更多的冲击能量,其整体结构破坏最小,冲击强度更高。     

钢包覆式活性破片侵彻双层铝靶的行为特性研究

为研究包覆式活性破片撞击双层铝靶的毁伤效应和机理,利用14.5 mm弹道枪,开展了同质量、同尺寸的惰性钢破片、钢包覆金属/聚合物型活性破片以不同着靶速度侵彻3 mm+3 mm双层间隔铝靶的实验,分析了活性破片冲击双层间隔铝靶的点火及毁伤机理。结果表明,当破片着速为491~1391 m/s时,两型破片对前靶的穿孔形态和机理相同,为圆孔及冲塞型穿孔,孔直径以及孔直径随着速变化规律也基本相同;当破片着速大于947 m/s时,活性破片对后靶的穿孔开始显著大于前靶,主要是因为两靶间诱发了剧烈化学反应,且破片着速越高,反应越剧烈,后靶的毁伤增强效应越显著,当破片着速为947~1391 m/s时,后靶穿孔面积平均为4.1倍破片截面积,最大为7.2倍;该弹靶条件下活性破片冲击点火阈值速度约为947 m/s。     

Modeling perforation in glass fiber reinforced composites subjected to low velocity impact loading

In this article, experimental results are presented investigating the response of glass fiber composites subjected to low velocity impact loading. The resulting load‐displacement traces and deformation modes have been used to validate a number of numerical models. Here, finite element models have been developed to predict the impact behavior of the composite plates. Damage in the woven glass‐fiber reinforced composite plate was modeled using the Hashin failure criteria. The influence of target size, projectile size, projectile shape, and striking location on the impact response of the composites was investigated. In general, good agreement was obtained in terms of the load‐displacement traces and the failure modes in the composite plates. It has been shown that the perforation energy increases rapidly with target thickness, with the numerical results closely agreeing with the experimental data. Similarly, the energy required to perforate the composite targets increases with increasing projectile diameter, with the failure mechanisms being similar in all cases. Finally, increasing the bluntness of the impactor resulted in a significant increase in the energy to perforate these targets. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Impact behavior of aramid fiber/glass fiber hybrid composites: The effect of stacking sequence

Aramid fiber/glass fiber hybrid composites were prepared to examine the effect of stacking sequence on the impact behavior of thin laminates. The effect of position of the aramid layer on the impact properties of hybrid composites was investigated using driven dart impact tester. The delamination area and fracture surface of hybrid composites were analyzed for correlation with impact energy. The addition of glass layer to aramid layer reduced the impact resistance of hybrid composite due to the restriction in the deformation of aramid layer. The position of aramid layer resulted in variations in the impact behavior of hybrid composites. When the aramid layer was at the impacted surface, the composite exhibited a higher impact energy. This was attributed to the fact that the flexible layer at the impacted surface in thin laminates can experience larger deformation. In three‐layer composites, the aramid fiber‐reinforced composite ( AAA ) exhibited the highest total impact energy due to high impact energy per delamination area (1EDA) in spite of low delamination area. Aramid fiber and glass fiber‐reinforced composites showed a different impact behavior according to the change of thickness. This was attributed to the difference in the energy absorption at interface between laminae.     

高性能纤维增强复合材料应用的研究进展

纤维增强复合材料具有质轻、高比强度和比模量、加工成型性好、耐冲击、耐腐蚀等特性,在轻量化材料领域有着广阔的发展前景,综合对比了玻璃纤维、碳纤维、芳纶及超高相对分子质量聚乙烯纤维等纤维增强复合材料在航空航天、汽车领域、能源工业、环保领域中的应用现状,认为碳纤维增强复合材料在轻量化、高性能化方面具有极大的优势及应用前景。     

Effect of stacking sequence on the compressive performance of impacted aramid fiber/glass fiber hybrid composite

Aramid fiber/glass fiber hybrid composites were prepared to examine the compressive performance of impacted composites. The effect of stacking sequence and surface treatment on compression after impact (CAI) performance of three‐layer hybrid composites was investigated with respect to delamination area. As the impact velocity increased, the laminates exhibited a significant reduction of compressive strength owing to larger delamination area within laminate. The surface treatment aramid fiber reduced the delamination area and enhanced the resistance to buckling. The strength reduction of laminate AAA was considerable because of wide delaminated region, whereas the residual strength of laminate GGG was not affected by impact energy because the laminate absorbed most of impact energy through formation of fiber cracks rather than delamination. Considering stacking sequence, the laminate GAG and GAA exhibited an energy threshold due to insensitivity to impact damage. As a result, the residual performance of composite was primarily dominated by delamination extent rather than fiber cracks.     

Co‐injection molding: Effect of processing on material distribution and mechanical properties of a sandwich molded plate

The effect of molding parameters on material distribution and mechanical properties of co‐injection molded plates has been studied using experimental design. The plates were molded with a polyamide 6 (PA 6) as skin and a 20% glass fiber‐reinforced polybutyleneterephtalate (PBTP) as core. Five molding parameters—injection velocity, mold temperature, skin and core temperature, and core content—were varied in two levels. The statistical analysis of the results showed that three parameters—Injection velocity, core temperature, and core content—were the most significant in affecting skin/core distribution. A high core temperature was the most significant variable promoting a constant core thickness, while core content was the most significant factor influencing a breakthrough of the core. Mechanical properties, such as flexural and impact strength showed a high correlation with the skin/core distribution. The slight increase in falling weight impact strength of the sandwich molded plates, compared to similar plates molded from PBTP only, could be explained from the failure process, which initiates in the brittle core and propagates through the ductile skins.     

Micromechanics of Failure Waves in Glass: II, Modeling

In an attempt to elucidate the failure mechanism responsible for the so-called failure waves in glass, numerical simulations of plate and rod impact experiments, with a multiple-plane model, have been performed. These simulations show that the failure wave phenomenon can be modeled by the nucleation and growth of penny-shaped shear defects from the specimen surface to its interior. Lateral stress increase, reduction of spall strength, and progressive attenuation of axial stress behind the failure front are properly predicted by the multiple-plane model. Numerical simulations of high-strain-rate pressure-shear experiments indicate that the model predicts reasonably well the shear resistance of the material at strain rates as high as 1 × 10₆/s. The agreement is believed to be the result of the model capability in simulating damage-induced anisotropy. By examining the kinetics of the failure process in plate experiments, we show that the progressive glass spallation in the vicinity of the failure front and the rate of increase in lateral stress are more consistent with a representation of inelasticity based on shear-activated flow surfaces, inhomogeneous flow, and microcracking, rather than pure microcracking. In the former mechanism, microcracks are likely formed at a later time at the intersection of flow surfaces. in the case of rod-on-rod impact, stress and radial velocity histories predicted by the microcracking model are in agreement with the experimental measurements. Stress attenuation, pulse duration, and release structure are properly simulated. It is shown that failure wave speeds in excess to 3600 m/s are required for adequate prediction in rod radial expansion.     

Energy absorptions and failure modes of 3D orthogonal hybrid woven composite struck by flat‐ended rod

Three‐dimensional (3D) orthogonal woven composite has high stiffness, strength, and energy absorption capacity along X, Y, and Z directions because there are no crimps in yarn. This paper presents mechanical behaviors and energy absorptions of the 3D orthogonal hybrid woven composite under transverse impact and quasi‐static loading by flat‐ended rod. The failure load and energy absorption of the composite increase with the increase in loading rate. The damage morphology of the composite coupon manifests the compression failure in the front side and tension failure in rear side. There are no delaminations in the composite coupons for both quasi‐static and impact loading for the existence of Z‐yarn in fabric structure. This phenomenon manifests the potential application of the 3D orthogonal woven composite to impact resistance areas. POLYM. COMPOS., 27: 410–416, 2006. © 2006 Society of Plastics Engineers