Papers by Keyword: Laminated Composite

Abstract: Taguchi based optimization of natural frequency of perforated stiffened hypars is performed to consider the role of fibre lamination, width/thickness ratio of shell and position of perforation centre along x- and y-direction. Natural frequency of stiffened shell is obtained for simply supported boundary condition using finite element procedure based on L27 orthogonal array (OA) considering three settings of each parameter. Main effect plot is analyzed to identify the significant parameters. Natural frequency becomes maximum for a combination of 45⁰ fibre lamination, width/thickness value of 20 and perforation centre position (0.4, 0.4). Interaction graphs identify the interaction parameters. ANOVA study provides the significant contribution of the parameters considered here. Present analysis identifies width/thickness as the most significant factor and other parameters yield very little significance while no interaction is found to be significant. Width/thickness value of shell yields major (98.64%) contribution to natural frequency and other factors yield very little significance. Residual analysis for natural frequency and confirmatory test validate the present study. S/N ratio gets improved by 38.3% at optimal condition compared to the initial parameter setting.

Abstract: In this paper, the post ballistic impact behaviour of kevlar-glass fibre hybrid composite laminates was investigated against 9×19 mm projectile. Eight different types of composite laminates with different ratios of kevlar woven fibre to glass fibre were fabricated using hand lay-up with epoxy matrix. Ballistic behaviour like ballistic Limit (V₅₀), energy absorption, specific energy absorption and Back Face Signature (BFS) were studied after bullet impact. The results indicated that as the Percentage of glass fibre is increased there was a linear increment in the ballistic behaviour. Addition of 16% kevlar fabric, composite sample meets the performance requirement of NIJ0101.06 Level III-A. Since the maximum specific energy absorption was observed in Pure Kevlar samples and the adding of glass fibre increases the weight and Areal Density of the sample, further investigations need to be carried out to utilize the potential of glass fibre for ballistic applications.

Abstract: Laminated metal composites are composed of alternating layers of metals or alloys, bonding together at their interface, which have gained extensive attention because of their advantages such as improved fracture toughness, impact behavior, corrosion, wear and damping capacity. Roll bonding is the most widely used method to process many metallic composites. In this study, we fabricated some kinds of Al/Ti/Al sandwich-like laminated composites by cryogenic roll bonding. We find that cryogenic roll bonding techniques can improve the mechanical properties of laminated composites. Finally, we will discuss the mechanism of improvement in bonding strength and mechanical properties.

Abstract: In order to obtain a real-time interlaminar crack fracture behavior of the laminate composites, in this paper we propose a method of extracting and measuring of interlaminar crack of laminated composite materials based on 2D image analysis via the Matlab software. Extracting the main crack image were conducted using the Matlab script including four different algorithms: the binarization, region growing, morphological, and skeleton thinning, and then a main interlaminar crack image with 1 pixel width were obtained. The length of the main crack was calculated through the sum of pixels of the skeletonized object. The calculated result was closed to the measured result, and the difference between the calculated value and measured value was 0.2%, which can prove the accuracy of the method in present work. The proposed method is of high precision, with strong anti-inference ability and experimental data is stable and reliable, which is helpful to study the crack propagation behavior of laminated composite materials.

Abstract: This paper adopts a flow-punched technology for laminated composite which combines jet-flow and carbon fiber piercing technology. The jet-flow-based preform forming experiment system is constructed, and jet flow technology is used to prepare the interlaminar reinforced carbon fiber composite materials. The reinforced carbon fiber bundle is shot into the microstructure of the laminated composite in all directions and laminated carbon fiber becomes an entire, and then it is treated by vacuum and curing process. This paper provides a technological approach to improve the quality of the laminated composite preform.

Abstract: Based on liquid fusion and atomic interdiffusion of TiB₂-based ceramic and 42CrMo steel, the ceramic-metal laminated composites with interfacial 3D-network span-scale graded microstructures were achieved by combustion synthesis in high gravity field. The presence of respective atomic concentration gradient of Ti, B, C, Fe and the others between the ceramic and the steel reasoned for continuously-graded interfacial microstructure in which the TiB₂ and TiC phases transform sub-micrometer, micro-nanometer grains from the micrometer ones. The Fe-based liquid flow from the ceramic to the steel substrate resulted in the 3D-network distribution of Fe-based alloy phases from the ceramic to the steel substrate. Hence, interfacial shear fracture presented the mixed mode consisting of intercrystalline fracture along fine TiB₂ platelets and ductile fracture in Fe-based alloy phases, presenting interfacial shear strength 415 ± 25 MPa of the laminated composite.

Abstract: W/TiNiNb shape memory alloy laminated composites were fabricated by vacuum hot press, forging and rolling. The microstructure, transformation behavior, mechanical behavior and damping capacity of the laminated composite were investigated by SEM, DSC, DMA and bending test, respectively. The results showed that the W layer and the TiNiNb shape memory alloy layer in the composite was about 15 μm and 5 μm, respectively. The TiNiNb alloy in the composite exhibited the reversible martensite transformation. The composite also had high damping capacity (tanδ=0.03). The three-point bending test showed various plateaus in the stress–strain curve due to delamination processes, which are suitable for enhancing the fracture toughness of the laminates. The flexure strength of the laminated composite was 1260 MPa.

Abstract: By taking Ti-B₄C and CrO₃-Al as the primary system and the subsystem respectively, the curve dependence of CrO₃-Al subsystem on the adiabatic temperature of the reactive system was calculated in chemical dynamics, and laminated composite with TiB₂-based ceramic to stainless steel was achieved without Al₂O₃ inclusions and microcracks at the interface, and the intermediate was clearly presented between the ceramic and the stainless steel through liquid fusion and liquid diffusion of the ceramic liquid and the molten steel. Because of the differences in constitutional diffusion and solid precipitation, the hybrid microstructures was presented in the intermediate, i.e. within the intermediate the ceramic and metallic phases in different size were alternately distributed to form 3-D net ceramic-metal microstructure, while the continuously-graded microstructure from the TiB₂ matrix ceramic to stainless steel was also presented in both volume fraction and size of the TiB₂ and TiC phases.

Abstract: Laminated composite of TiB₂ based ceramic to Ti-6Al-V alloy in graded microstructure were achieved by combustion synthesis in ultra-high gravity field. XRD and FESEM results showed the presence of the graded microstructures at the joint which was characterized by multilevel (TiC_1-x-TiB-TiB₂ + TiB₂-Ti-TiC_1-x-TiB + TiB₂-TiC_1-x-TiB-Ti + TiB-TiC_1-x-Ti + TiC_1-x-Ti) and multiscale (micro-submicro-nano) of the size and the distribution of TiB₂ phases and TiB phases. It was considered that liquid fusion, atomic interdiffusion and a series of metallurgical reaction during solidification were reasoned for the continuously-graded microstructure from the ceramic to Ti alloy. Ballistic mass effectiveness coefficients of TiB₂ based ceramic and the laminated composite with TiB₂ based ceramic to Ti alloy were calculated to be 3.25 and 7.35 respectively by DOP test. The continuously-graded microstructures at the joint from the ceramic to Ti ally was considered to effectively reduce acoustic impedance mismatch between the ceramic and the metal, resulting in the enhanced ballistic performance of the target against the projectile by initiating intensive shear coupling effect.

Abstract: The tearing behavior of fiber-reinforced laminated composite textile plays the key role in the decision of mechanics performance of high altitude airship envelop material, even directly deciding its safety and stability. This paper, based on typical woven fabricated fiber yarns’ characteristics of geometry and mechanics, adopts Euler-displacement deformation analysis to explore yarn bundles deformation effects on tearing behavior and strength of envelope material with prefabricated damage and crack. Also, models with prefabricated crack with different size and textile density are respectively built to find factors that affect tearing behavior and strength of envelope material. From tests, it can be observed that the built models for predicting its tearing strength are in conformity with the experimental data. Nonlinear relationship is reflected between the initial crack width or yarn bundles density with tearing strength. Conclusively, the methods and models adopted in this paper provide an effective and innovative mind on tearing behavior and strength of fiber reinforced envelope material and make the foundation for its engineering application.