Applied Composite Materials最新文献

A novel material, i.e. 2.5D three-harness-twill warp-reinforced woven composites (2.5D-THT-WR-WC), is proposed, which has wide engineering applications. In this work, geometrical relationships with different meso features are discussed through X-CT characterization. On this basis, six unit-cell models with different meso geometrical features are established considering different weft yarn arrangement densities M_F, and numerical simulations are carried out combined with a developed progressive damage model. Comparison with the experimental results shows that the maximum prediction errors of modulus and strength are 6.3% and 11.7%, respectively. Therefore, the developed numerical simulation model can reasonably predict the mechanical behavior of 2.5D-THT-WR-WC. Additionally, as the M_F increases, the mechanical properties in the warp and weft directions decrease and increase, respectively, owing to the inclination angle and the extrusion condition between adjacent layers of the binder yarns. This work provides a design reference for the structural application of 2.5D-THT-WR-WC, which has a significant engineering value.

This paper proposes a finite element (FE) analysis approach in meso-scale to predict the mechanical behavior, including elastic moduli and tensile strength, of SiC nanowires reinforced aluminum matrix (SiC_nw/Al) composites. The study investigates the influence of the volume fraction and the aspect ratio of the SiC nanowires on the mechanical properties of the composites by employing the representative volume elements (RVE) models. The FE results successfully predict the elastic moduli and strength properties of the SiC_nw/Al composites, exhibiting consistency with both the experimental findings and the theoretical predictions. In terms of microstructure, the elastic moduli and strength of the composites generally exhibit an increasing trend with higher volume fractions. However, the aspect ratio demonstrates a more intricate behavior, initially increasing and eventually reaching a saturation value as the aspect ratio increases. The results also reveal significant effects of the extrusion treatment on the mechanical properties of the SiC_nw/Al composites, leading to an increase in the elastic moduli and strength along the direction of the nanowires. The numerical approach presented in this work provides an accurate means of predicting the mechanical properties of SiC_nw/Al composites, thereby serving as a valuable reference for designers.

The hybridization of natural and synthetic fibers is an alternate method to balance the performance and environmental friendliness of fiber metal laminates (FMLs). This research aims to fabricate hybrid aluminum (A)/ carbon fiber (C)/ pineapple leaf fiber (P) reinforced epoxy FMLs with different stacking sequences by the vacuum-assisted resin transfer molding (VARTM) technique. The fabricated hybrid FMLs were subjected to tensile, flexural, thermogravimetric analysis (TGA), and water absorption tests. The tensile and flexural strength of hybrid A₁ (ACPCA) surpassed those of non-hybrid A_P (APPPA) by 252.77% and 165.08%, respectively. The thermal test shows that the hybrid FMLs A₁ with higher CF content leads to better thermal stability than A₂ (APCPA). In addition, from the water absorption test, the A_P and A₂ FMLs, with PALF as outer layers of core materials, absorbed moisture exceeding 6% after 10 weeks, compared to A_C (ACCCA) and A₁ with CF as outer layers of core materials, which only reached up to 2.88% and 4.22%, respectively. From this study, it is worth pointing out that the hybrid A₁ showed comparable performance to non-hybrid A_C. Thus, the appropriate hybridization of synthetic and natural fibers can broaden the scope of the practical application of FMLs with improved environmental friendliness in the automotive industry.

In this paper, the effect of axial yarns on progressive bending damage of braided composite tubes is predicted by simulation. In this paper, Abaqus mesoscopic finite element simulation of lateral collapse of biaxial and triaxial braided composite tubes is carried out. Firstly, the specific material parameters of impregnated yarn and resin were determined by micro-scale periodic unit cell (RUC) model and experiment, and the material properties of resin matrix and impregnated yarn were defined. In the simulation, the resin failure process was simulated according to the ductility and shear damage criteria, and the damage of fiber reinforcement was predicted according to the Hashin criteria. The simulation results show a good correlation with the experimental results, indicating that the Abaqus simulation model established in this paper can further explain the bending damage evolution behavior of biaxial and triaxial braided pipes, and further understand the damage mechanism of braided composite tubes. At the same time, the addition of axial yarn greatly improves the bearing stress and energy absorption capacity of braided composite tube. Finally, the experimental and simulated damage profiles of the two samples were compared.

Carbon fiber-reinforced composites (CFRCs) have been widely used in automotive, aerospace, sports equipment, and other industrial fields, due to the higher strength-to-weight ratio and modulus compared with metals and alloys. Innovations in additive-manufactured CFRCs have opened up new avenues for designing and manufacturing high-performance, low-cost complex composite structures. According to the structure and substrate type of carbon fiber, this paper firstly reviews the existing feasible technologies as well as their key elements and focuses on the research of additive manufactured CFRCs by fused deposition molding (FDM) and selective laser sintering (SLS). Furthermore, the typical applications and envisions of additive manufactured CFRCs were elaborated. Moreover, the existing challenges and problems are summarized from the aspects of materials, equipment, and software. In the future, more interdisciplinary research is needed on advanced materials, multiple processes, advanced equipment, and structural design, and there will be a broader research space for robot-assisted additive manufacturing and green manufacturing methods.

The main aim of this paper was to make rivet joints of metal-composites without drilling the laminated composites. Experimental and numerical approaches were used to show the efficiency of this manufacturing method and its effects on the energy absorption of the metal-composites joint under bending loading. In this research, E-glass/epoxy laminated composites were joined to Al 6061-T6 and ASTM A283 St Grade C. Various number of rivets, i.e., 1, 2 and 4, and two arrangements, i.e., square and diamond, were embedded in the laminated composites. Then, the single lap joints were tested under flexural loading. A 3D finite element (FE) analysis at the meso-scale was performed to compare the response of woven E-glass/epoxy composites with and without drilling. Since the meso-scale model could not be applied to simulate the considered single lap joint, a refined micro-blocks model was also proposed for the regions affected by the riveting process. The experimental results showed that the embedding method significantly improves the energy absorption of the joints. This improvement was around 15% and 28–62% for the Al/composites and St/composites samples, respectively. Besides, the samples with the diamond arrangement have the best flexural properties. The FE analysis demonstrated that the results obtained by the refined micro-blocks model compare well with the experimental data.

This study explores the variation in mechanical properties of additively manufactured composite structures for robotic applications with different infill densities and layer heights using fused deposition modelling (FDM). Glass fibre-reinforced polyamide (GFRP), and carbon fibre-reinforced polyamide (CFRP) filaments are used, and the specimens are printed with 20%, 40%, 60% and 100% infill density lattice structures for tensile and three-point bending tests. These printed samples are examined in the microscope to gain more understanding of the microstructure of the printed composites. To characterise the mechanical properties, a set of tensile and three-point bend tests are conducted on the manufactured composite samples. Test results indicate the variations in tensile strength and Young’s modulus of specimens based on the printing parameters and reveal the tensile and bending behaviour of those printed composite structures against varying infill ratios and reinforcing fibres. The experimental findings are also compared to analytical and empirical modelling approaches. Finally, based on the results, the applications of the additively manufactured structure to the robotic components are presented.

This paper aims to assess how the impact behaviors of multi-ply flexible fabrics change by different projectile impacts using numerical simulations. The paper starts with the generation and verification of a multi-scale finite element model. Subsequently, a ten-ply flexible fabric is numerically subjected to the impacts of six different types of projectiles: 22-caliber conical, spherical, and right circular cylindrical (RCC), as well as 0.30-caliber conical, spherical, and RCC. The remaining sections of the paper explore the ballistic protection behavior of the ten-ply flexible fabric from all aspects, including ballistic limits, changes in energy, displacements, and damage patterns. The research findings suggest that the latter plies of the fabric have significant importance in dissipating energy compared to the initial plies, regardless of the type of projectile impact. This is because the first plies of the fabric tend to fail prematurely and reach their maximum strain limit before they can effectively dissipate energy. Although the initial plies showed consistent trends across all projectiles in terms of energy transfer, the size of the post-damage area and failure modes were influenced by the characteristics of the projectiles. Overall, this research emphasizes the need to explore the ballistic capability of multi-ply flexible woven fabrics impacted by different projectiles to improve both the construction and effectiveness of soft body armor.

Honeycomb crash absorbers have been widely studied as energy absorption devices for use in automotive industries. However, none of these investigations have studied the side impact of empty and foam-filled honeycomb absorbers and adding stiffeners between the different layers of the corrugated sheets which are composing the honeycomb structure to analyse the structure under transverse (L-direction) impacts. In this paper, the foam-filled and reinforced honeycomb crash absorbers are investigated under axial (T) and transverse (L) loading directions. Experimental results for both empty and foam-filled specimens under quasi-static and impact loads were implemented to validate the developed finite element model. Finite element analysis (FEA) was performed to find out the crashworthiness behaviour of the structure under axial and transverse impacts according to road conditions. Finally, a new design of stiffened honeycomb crash absorber was developed and investigated to reduce the level of acceleration experienced by the passengers during the crash event. In this regard, it is concluded that all the requirements related to the energy absorption capabilities and generated deceleration under impact loading can be met by introducing an advanced method to reinforce honeycomb absorbers using stiffeners. It is also proven that the thickness of these stiffeners will not significantly influence the force levels. Due to increase of wall thickness from 1 to 3 mm, the mean crushing force increased from 129 kN to 148 kN. This growth is not sufficient as the goal is to obtain a mean crushing force of 300 kN. Thickening the stiffeners would lead to a loss of efficiency of the structure, as the small increase in mean force would not make up for the gain in mass. Thus, increasing the corrugated sheet’ thickness becomes necessary.

The purpose of this work was the evaluation of electrical conductivity and piezoresistive response of seawater aged glass fiber/epoxy composites (GF/E) with the incorporation of multiwall carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs) and their hybrid combination (MWCNT/GNP) at two mixing ratios (7:1 and 3:1). Seawater exposure leads to the phenomenon of moisture absorption in GF/E, which negatively affected their bending properties, causing a higher susceptibility to damage mechanisms related to matrix cracking, fiber/matrix interfacial debonding and delamination. However, the addition of MWCNT/GNP hybrids to the GF/E composites induced a positive effect on the electrical response resulting in improved piezoresistive properties (strain sensitivity) and damage sensing under monotonic flexural loading. The results of piezoresistive response experiments also confirmed excellent strain sensing capabilities under cyclic loading condition for both unaged and aged composites, demonstrating the efficiency of using the hybrid combination of MWCNTs and GNPs for electrical sensing applications of composite structures in seawater aged conditions. It was found that the 3:1 mixing ratio allowed better electrical performance of GF/E composites and piezoresistive capability was preserved even after sea water aging.