Effect of basalt fiber hybridization on the impact behavior under low impact velocity of glass/basalt woven fabric/epoxy resin composites

The low velocity impact behavior of E-glass/basalt reinforced hybrid laminates, manufactured by resin transfer moulding technique, was investigated. Specimens prepared with different stacking sequences were tested at three different impact energies, namely 5 J, 12.5 J and 25 J. Residual post-impact mechanical properties of the different configurations were characterized by quasi static four point bending tests. Post-impact flexural tests have been also monitored using acoustic emission in order to get further information on failure mechanisms. Results showed that basalt and hybrid laminates with an intercalated configuration exhibited higher impact energy absorption capacity than glass laminates, and enhanced damage tolerance capability. Conversely, the most favorable flexural behavior was shown by laminates with symmetrical sandwich-like configuration (E-glass fiber fabrics as core and basalt fiber fabrics as skins).     

三维正交机织玄武岩/环氧树脂复合材料高温老化后低速冲击性质

研究了三维正交机织玄武岩/环氧树脂复合材料在180℃高温环境下老化不同时间后的低速冲击力学性能,测试得到了不同老化时间的试样在低速冲击过程中的载荷-位移曲线。研究发现:随着老化时间增加,三维正交机织玄武岩/环氧树脂复合材料能承受的最大载荷下降,位移逐渐增加,载荷-位移曲线斜率逐渐下降;随着冲击能量增加,老化条件相同的三维正交机织玄武岩/环氧树脂复合材料试样最大承受载荷增大,位移和曲线斜率增加。对高温老化后三维正交机织玄武岩/环氧树脂复合材料试样进行SEM观察,发现纤维与树脂基体脱粘有裂纹产生,且裂纹数目和面积随着老化时间延长而增加。      

Hybrid composites based on aramid and basalt woven fabrics: Impact damage modes and residual flexural properties

The low-velocity impact behaviour of hybrid laminates reinforced with woven aramid and basalt fabrics and manufactured by resin transfer moulding was studied. Specimens with different stacking sequences were tested at three different energies, namely 5, 12.5 and 25 J. Residual post-impact properties of the different configurations of aramid/basalt hybrid laminates were characterized by quasi static four point bending tests. Post-impact flexural tests have been monitored using acoustic emission in order to get further information on failure mechanisms. Results indicate that hybrid laminates with intercalated configuration (alternating sequence of basalt and aramid fabrics) have better impact energy absorption capability and enhanced damage tolerance with respect to the all-aramid laminates, while basalt and hybrid laminates with sandwich-like configuration (seven basalt fabric layers at the centre of the laminate as core and three aramid fabric layers for each side of the composite as skins) present the most favourable flexural behaviour.     

An experimental investigation on the impact behavior of hybrid composite plates

In this experimental study, the impact behavior of hybrid composite plates has been investigated. The increasing impact energy was performed on two types of hybrid composite plates (glass–carbon/epoxy) until complete perforation of specimens. An energy profiling method, showing the relationship between impact energy and absorbed energy, was used together with load–deflection curves to determine the penetration and perforation thresholds of hybrid composites. The failure processes of damaged specimens for different impact energies were evaluated by comparing load–deflection curves and images of damaged samples taken from impacted sides and non-impacted sides. Cross-sections of damaged specimens were also inspected visually and discussed to assess the extent of damage, such as fiber fracture in layers, expansion of delaminations between adjacent layers. The perforation threshold of hybrid composite impacted from surface with carbon fibers was found approximately 30% higher than that of surface with glass fibers.     

Impact response of woven composites with small weaving angles

This paper presents experimental investigations on impact response of woven composites with various weaving angles between interlacing yarns. A method for preparing novel woven composites with small weaving angles is presented. The effects of the weaving angle on the impact characteristics such as peak force, contact duration, maximum deflection and absorbed energy are also examined. An energy profiling method seems to be useful for identifying the penetration and perforation thresholds of the woven composites. The damage process of individual woven composites can be reconstructed from comparing the corresponding load–deflection curves, energy profile and images of damaged specimens. The study concludes that the energy absorption capability and perforation threshold of woven composites can be significantly improved by using a small weaving angle between interlacing yarns. For example, the perforation threshold of [0/20]₄ woven composite, which has a weaving angle of 20° between interlacing yarns, is about 40% higher than that of [0/90]₄ woven composite, which has a weaving angle of 90° between interlacing yarns. The higher energy absorption capability of [0/20]₄ over [0/90]₄ is attributed to a lower stiffness caused by a more polarized fiber orientation and a smaller fiber crimp, resulting in a larger maximum deflection, a more extended damage zone and a larger amount of fiber pullout.     

泡沫铝夹层结构复合材料低速冲击性能

以泡沫铝为夹芯材料,玄武岩纤维(BF)和超高分子量聚乙烯纤维(UHMWPE)复合材料为面板,制备夹层结构复合材料。研究纤维类型、铺层结构和芯材厚度对泡沫铝夹层结构复合材料冲击性能和损伤模式的影响规律,并与铝蜂窝夹层结构复合材料性能进行对比分析。结果表明:BF/泡沫铝夹层结构比UHMWPE/泡沫铝夹层结构具有更大的冲击破坏载荷,但冲击位移和吸收能量较小。BF和UHMWPE两种纤维的分层混杂设计比叠加混杂具有更高的冲击破坏载荷和吸收能量。随着泡沫铝厚度的增加,夹层结构复合材料的冲击破坏载荷降低,破坏吸收能量增大。泡沫铝夹层结构比铝蜂窝夹层结构具有更高的冲击破坏载荷,但冲击破坏吸收能量较小;泡沫铝芯材以冲击部位的碎裂为主要失效形式,铝蜂窝芯材整体压缩破坏明显。     

不同层数的超高分子量聚乙烯纬平针织复合材料冲击损伤

研究了不同层数超高分子量聚乙烯(UHMWPE)纤维/环氧树脂纬平针织复合材料的冲击性能,并讨论了其冲击损伤模式。复合材料板分别为4、6、8层纬平针织结构,采用真空辅助树脂传递模塑(VARTM)工艺层合而成,以不同的冲击能量(10~55J)冲击复合材料板直至层合板被穿透,得到冲击能量与吸收能量关系图以及接触力-挠度曲线。分析了不同冲击能量下,复合材料中织物的损伤形式和破坏过程。研究结果表明:在3种针织结构复合材料中,8层纬平针织结构承受载荷的能力最强,6层纬平针织结构次之,4层纬平针织结构最差;随着冲击能量的增加,3种试样的冲击挠度均增大;基体开裂、纤维断裂是试样被渗透时有效的损伤模式,基体和纤维断裂是试样被穿孔时有效的损伤模式。     

The role of temperature on impact properties of Kevlar/fiberglass composite laminates

This paper demonstrates results of an experimental study on Kevlar/fiberglass composite laminates subjected to impact loading at variable temperatures. The effect of temperature on maximum energy, elastic energy, maximum deflection, maximum impact force, ductility, and compression after impact was studied at several low velocity impact energy levels (8, 15 and 25 J). The temperatures considered were in the range of −50 to 120 °C. Results indicated that impact performance of these composites was affected over the range of temperature considered. Testing at ambient temperature is not fully sufficient and therefore additional testing must be performed for full understanding of composite laminate properties.     

Impact and post impact behavior of layer fabric composites

In this study, the effect of impact and post impact behavior of E-glass/epoxy composite plates having different layer fabrics were investigated by considering energy profile diagram and the related load–deflection curves. Different impact energies (5 J–60 J)were subjected to the plates consisting of eight layers of plain weave (1D), double (2D) and triple (3D) layer fabrics. The impact tests were continued until complete perforation of layer fabrics. The damage modes and damage processes of layer fabrics under varied impact energies were also discussed. At the end of the impact tests, the damaged samples were mounted into a compression apparatus to determine the Compression After Impact (CAI) strength of layer fabric samples. The results of these impact and post impact tests showed that contact force occurring between the impactor and the composite specimen increased and the CAI strength reduced by increasing the impact energy. The objective of this study was to determine the perforation threshold of E-glass/epoxy composite plates having different layer fabrics as plain weave (1D), double (2D), and triple (3D) layer fabrics.     

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.     

Impact loading on fibre metal laminates

Static identation and low and high velocity impact tests are conducted on specimens with a circular clamped test area. Monolithic A1 2024-T3 and 7075-T6, various grades of Fibre Metal Laminates (FML), and composites are tested. The energy to create the first crack for FML with aramid and carbon fibres is comparable to fibre reinforced composite materials and is relatively low compared to A1 2034-T3 and FML with R-glass fibres (GLARE). GLARE laminates can show a fibre critical or aluminium critical failure mode. The dent depth after impact of FML is approximately equal to that of the monolothic aluminium alloy. The damage size of FML after impact is considerably smaller than of glass and carbon fibre composite materials. The maximum central deflection during low velocity impact loading is approximately equal to the static deflection at the same energy (i.e., area under load-deflection curve). This deflection can be modelled using the simplified Von Kármán equations neglecting the contribution of the in-plane displacements. For these calculations the shape of the specimen under load was measured. This shape was approximately independent of the central deflection and the type of material.     

Macroscale assessment of low-velocity impact on hybrid composite laminates

Composites are usually brittle materials and have low impact properties. Structural dimensions, stacking sequence, ply materials, ply thicknesses and ply angles are standard variables that influence composite‘s performance against impact loads. Stacking sequence in hybrid laminates affects the failure and impact resistance. Failure mechanisms at the low-velocity impact of a rigid object in hybrid laminates are complex, and the subsurface damage in a composite laminate cannot be detected directly. However, various simulation platforms make it easy to see the impact damage between the plies of laminate. This paper numerically investigated the effect of stack sequence and hybridization of two fiber types against low-velocity impact. The current study adopted four-layer composite laminates of carbon and glass fiber layers with a stacking plan [C/C/C/C], [C/G/C/G] and [G/C/G/C], having lay-up angles as [0°/45°/−45°/90°]. Keeping the impactor mass and the incident velocity constant, the laminates were subjected to low-velocity impact. The damage contours for a failure mode were recorded and compared at the ply level. The numerical study resulted in impact imitations showing comparisons of the damage contours using Hashin failure criteria. Hybrid laminates display better performance in absorbing impact energies; however, hybrid laminates experienced more subsurface damage due to more impact energy absorption.     

Impact characterization of glass/epoxy composite plates: An experimental and numerical study

This study presents the effects of impact energy, impactor mass and impact velocity on the maximum contact force, maximum deflection, contact time, absorbed energy, and overall damage area of glass/epoxy laminated composites, experimentally and numerically. The stacking sequence of the composite plates was chosen as [0°/30°/60°/90°]_S. The impact event was simulated and analyzed by using 3DIMPACT finite element code. The overall delamination area obtained from experimental study and numerical analyses were also examined. It is seen that the numerical results are in good agreement with experimental results.     

The effect of fibre content on the mechanical properties of hemp and basalt fibre reinforced phenol formaldehyde composites

In this study, mechanical properties such as tensile, flexural and impact strengths of hemp/phenol formaldehyde (PF), basalt/PF and hemp/basalt hybrid PF composites have been investigated as a function of fibre loading. Hemp fibre reinforced PF composites and basalt fibre reinforced composites were fabricated with varying fibre loading i.e. 20, 32, 40, 48, 56 and 63 vol%. The hybrid effect of hemp fibre and basalt fibre on the tensile, flexural and impact strengths was also investigated for various ratio of hemp/basalt fibre loading such as 1:0, 0.95:0.05, 0.82:0.18, 0.68:0.32, 0.52:0.48, 0.35:0.65, 0.18:0.82 and 0:1. Total fibre loading of the hybrid composites was 40 vol%. The results showed that the tensile strength and elongation at break increase with increasing fibre loading up to 40 vol% and decrease above this value for hemp fibre reinforced PF composite. Similar trend was observed for flexural strength and the maximum value was obtained for 48 vol% hemp fibre loading. Impact strength of hemp/PF composite showed a regular trend of increase with increasing fibre loading up to 63 vol%. Tensile strength, flexural strength and impact strength values of basalt/PF composites were found to be lower compared to hemp/PF composites. The tensile strength and elongation at break of basalt/PF composite increased by incorparation of basalt fibre up to 32 vol% and decreased beyond this value. Flexural strength of basalt/PF composite decreased linearly with fibre loading. However, the maximum impact strength was obtained for 48 vol% basalt fibre loading. For hemp/basalt hybrid PF composite, the tensile strength decreased with increasing basalt fibre loading. On the other hand, the flexural and impact strengths showed large scatter. The maximum flexural strength value was obtained for 0.52:0.48 hemp/basalt ratio. Corresponding value for impact strength was obtained for 0.68:0.32 hemp/basalt fibre ratio.     

Hybridization effect on the mechanical and dynamic mechanical properties of curaua composites

This study aims to evaluate the performance of curaua/glass hybrid composites focusing on mechanical and dynamic mechanical analysis (DMA). Composites with distinct glass/curaua fiber loading ratios were studied. Flexural strength and modulus, impact strength and Barcol hardness increased for higher glass fiber content. The same was found for storage and loss modulus. The activation energy of the relaxation process in the glass transition region showed a maximum for the all-glass composite, corroborating with the results of concentration of elastic chains (υ_e). Cole-Cole plots were obtained and found to follow the same trend regardless of the glass content, whereas peak height and peak width at half-height were maximum for the all-glass composite.     

Influence of Fiber Orientation and Fillers on Low Velocity Impact Response of the Fabric Reinforced Epoxy Composites

The low velocity impact response of the epoxy composite materials, which were reinforced with various hybrid contents, such as plain pure or hybrid fabrics (carbon, aramid and glass fibers and copper wires) and filler mixtures into the epoxy matrix (aramid powder, potatoes starch, barium ferrite and carbon black) was investigated using a drop weight impact machine. The aim of this study was to characterize and assess the effects of fiber orientation at various angles and filler mixtures into epoxy matrix on the impact response. All the tests were carried out at constant impact energy, namely 90.629 J. Results indicated that the fiber orientation at various angles has a positive effect on impact response, mainly in the case of aramid fabric reinforced composites. In terms of influence of fillers addition into matrix, it was obtained an improvement on the impact response of hybrid fabric reinforced composite as compared to the pure fabric reinforced composites.

     

Investigation of knitting architecture on the impact behavior of glass/epoxy composites

In this study, the effect of impact and post-impact behavior of E-glass/epoxy composite plates having different knitted fabrics were investigated by considering energy profile diagram and the related load–deflection curves. Different impact energies (5–25 J) were subjected to the plates consisting of eight layers of Plain [P]₈, Milano [M]₈, and Rib [R]₈ knitted fabrics. The impact tests were continued until complete perforation of layer fabrics. The damage modes and damage processes of layer fabrics under varied impact energies were also discussed. At the end of the impact tests, the damaged samples were mounted into a compression apparatus to determine the Compression after Impact (CAI) strength of layer fabric samples. The results of these impact and post-impact tests showed that the maximum contact force was observed in the [R]₈ fabric and the minimum contact force was observed in the [P]₈ fabric and the CAI strength reduced by increasing the impact energy.     

玻璃纤维/环氧乙烯基酯树脂复合材料的层间增韧及其低温下低速冲击性能

采用真空辅助成型工艺(VARI)制备了四种无纺布(聚酰胺(PA)、聚氨酯弹性体橡胶(TPU)、乙烯-醋酸乙烯共聚物(EVA)、共聚酯(PEs))层间改性的玻璃纤维/环氧乙烯基酯树脂(GF/EVER)复合材料层合板.在温度为20℃下进行落锤冲击实验,对比分析了不同层间改性的GF/EVER复合材料层合板的低速冲击响应特性和...     

Effect of repeated impacts on the response of plain-woven hybrid composites

The repeated low-velocity impact responses of hybrid plain-woven composite panels were studied by drop-weight experiments. Non-hybrid S2-glass-fiber/toughened epoxy and IM7 graphite fiber/toughened epoxy as well as hybrid S2-glass–IM7 graphite fiber/toughened epoxy composite panels were impacted repeatedly using a pressure-assisted Instron-Dynatup 8520 instrumented drop-weight impact tester. During the low-velocity impact tests, the time histories of impact forces, absorbed impact energies and panel central deflections were recorded. The relations between the impact force and central deflection, whose slope represented the dynamic contact stiffness, were then constructed. The damaged specimens were inspected visually and using the ultrasonic C-Scan method. The effects of hybridization and lay-up sequence on the repeated drop-weight impact responses of woven composites were investigated. It was observed that damage accumulations could be slowed down using hybridization. It was also witnessed that the lay-up configuration of a hybrid composite had a significant influence on damage accumulation rate. The hybrid specimens with glass–epoxy skins survived the double number of successive impacts compared to hybrid specimens with graphite–epoxy skins.     

Effect of Nylon-66 nano-fiber interleaving on impact damage resistance of epoxy/carbon fiber composite laminates

Sixteen-ply quasi-isotropic composite laminates of plain and interleaved AS4/3501-6 composite laminates clamped all around were impact tested to assess the improvement in impact resistance of composite laminates that have been interleaved by electrospun Nylon-66 nanofabric. The impact velocity, force, and energy ranged from 2.0 to 4.0 m/s, 900 to 2100 N and 0.46 to 1.80 J, respectively. Based on this preliminary study, results showed that; polymer nanofabric interleaving marginally increased the laminate thickness, by about 2.0%. Polymer nanofabric interleaving increased the threshold impact force by about 60%, reduced the rate of impact damage growth rate to one-half with impact height and reduced impact damage growth rate from 0.115 to 0.105 mm²/N with impact force. The concept has merit for more detailed study for optimizing and for multi-functionalizing fiber reinforced composite laminates.