Composites Part C Open Access最新文献

The aim of this study is to explore the use of sustainable basalt fiber (BF) as compared to glass fiber and talc in injection molded engineering polyamide 6,6 (PA 6,6) plastic composite. Basalt fibers having lengths of 3 mm and 12 mm were added to PA 6,6 at 23 and 30 wt.% to fabricate the composites. The addition of basalt fiber restricts the mobility of the polymer chain in the composites, leading to its increased viscosity. Rheological results showed that the out-of-phase response to the applied stress indicated that the 3 mm basalt fiber composite could dissipate more energy, and the elastic behaviour of the composite under deformation increased with increasing basalt fiber wt.%. The fiber length had a larger effect on the mechanical properties of the composites as compared to the fiber load. The 12 mm basalt fiber composites at 23 wt.% and 30 wt.% produced higher tensile strength and modulus than the 3 mm basalt fiber composites while the 3 mm basalt fiber composite at 30 wt.% resulted in a 25 % increase in flexural strength. The experimental and the theoretical modulus predicted by the rule of mixtures showed an interaction between the matrix and the basalt fiber. Morphological analysis shows more agglomeration in composites with 3 mm fiber than the 12 mm. Glass fiber-reinforced PA 6,6 showed slightly higher performance than basalt fiber-reinforced PA 6,6. However, the basalt fiber-reinforced composites demonstrated better performance in tensile strength, flexural modulus, flexural strength, and heat deflection temperature than talc-reinforced composites.

The research focus has shifted towards lightweight structures with high energy absorption capabilities due to advancements in automotive safety technology. This study specifically investigates the impact of cross-sectional area on the energy absorption characteristics of hemispherical composite shells. The experimental phase involves characterizing a glass fiber epoxy composite, followed by the manufacture of hemispherical composite shell specimens with varying cross-sectional areas. These specimens undergo quasi-static axial compressive loading, and the energy absorption parameters are analyzed. The results indicate a significant influence of the composite cross-sectional area on the crushing behavior of hemispherical shells, with a observed decrease in specific energy absorption as the cross-sectional area increases. Additionally, a 3D Finite Element (FE) model is created using ABAQUS FE code to numerically simulate the crushing process. The model’s predictions are compared and validated against experimentally measured values, demonstrating a satisfactory correlation.

In this study, an analytical and numerical analysis of a hybrid sandwich structure with a lattice core produced by additive manufacturing with composite facesheets is carried out. This paper aims to analytically calculate the mechanical behavior of the hybrid sandwich structure under three-point bending and to verify the results by the finite element method. The analytical method used in this article for the analysis of the composite sandwich structure is the First-Order Shear Deformation Theory (FSDT). The numerical analysis of the hybrid sandwich structure was performed in ANSYS. In the analyses, homogenized models of lattice structures, which had been previously validated, were employed to reduce the number of elements and thereby save time during the solution process. As a result of the study, an extensive investigation into the deformation, shear, and normal stress values of sandwich structures with lattice cores of varying aspect ratios has been carried out. The findings suggest a potential for optimization in lightweight structures, which could lead to innovative advancements in design and manufacturing processes within the aerospace and automotive sectors.

Bacterial wound infections are prevalent in daily life. However, conventional tissue adhesives lack antimicrobial properties. In this study, a redox method was employed to prepare a nano-silver solution with tannic acid as a dispersant. Subsequently, the nano-silver solution was combined with the precursor solution of the hydroxyethyl methacrylate/vinylpyrrolidone (HEMA/NVP) hydrogel. Finally, it was put under ultraviolet light to produce the hydrogel. The hydrogel exhibits remarkable extendibility (1223 %), an elastic modulus compatible with human skin tissue (3.7 ± 0.5 kPa), the strong adhesion to porcine skin tissue (24.67 ± 1.15 kPa) markedly exceeds that achieved by clinically utilized fibrin glue, low swelling ratio (75 ± 1.55 %), and demonstrates good in vitro antimicrobial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, it displays excellent biocompatibility with fibroblast cells (NIH/3T3) with cell viability above 80 %, favorable blood compatibility with goat blood, and moderate coagulation ability. It provides more possibilities for clinical wound repair.

Carbon fibre reinforced polymer (CFRP) laminates are used in various studies as Li-ion polymer (LiPo) battery packaging. However, their suitability as a packaging material is not well understood. The present study investigates the liquid absorption (water and lithium bis(trifluoromethanesulfonic)imide (LiTFSI) electrolyte immersion tests) and barrier layer properties (water vapour transmission rate (WVTR) and oxygen transmission rate (OTR) tests) of a 200 gsm woven CFRP laminate to assess its suitability as a battery packaging material. This is the first study to show that prolonged immersion in battery electrolyte does not change the mechanical properties of a woven CFRP laminate. Hence, the CFRP laminate may be suitable for structural battery components, such as current collectors and electrodes. However, CFRP should not be used as battery packaging, as OTR and WVTR values of the CFRP laminate were found to be five and one order of magnitudes higher than typical battery pouch materials (i.e. aluminium foil), respectively.

In this study, undulations and their influence on the longitudinal compressive strength of a unidirectional glass fiber reinforced polymer (GFRP) composite are investigated theoretically and experimentally. The objective of this research is to explore the failure mechanisms in FRP and to characterize the mechanical properties of FRP as a function of fiber orientation. For this purpose, a multiscale material model is developed that considers a stochastic fiber orientation distribution (FOD) and models matrix fracture-initiated failure. The relationship between compressive strength and undulation is investigated experimentally on standardized specimens made of unidirectional GFRP. The fiber orientations are measured using X-ray computed tomography and ImageJ image analysis, resulting in a binormal distribution of fiber orientations in the series of samples tested. To examine the failure process in detail, the compression tests are simulated using finite element analysis (FEA). Both the FEA results and the measured compressive strengths confirm the model assumption of matrix fracture-initiated failure under longitudinal compressive loading. The presented analytical model realistically represents the correlation of compressive strength with the FOD.

An experimental method was developed to examine the dynamic compression properties of structured polyurethane composites used as press belts within a shoe press of a paper machine. The objective was to investigate the influences of the geometrical surface structure and the matrix material composition on the compression properties. Two polyurethane formulations were tested under varying specimen conditions. The results show that the dynamic compression modulus increases with the applied load rate and that temperature and water saturation reduce the influence of dynamic effects on the compression modulus. Furthermore, it was observed that modifications of the matrix material have a more significant impact on the dynamic compression modulus than adaptions in the geometrical structure. This is addressed to the relatively small variations in possible surface designs. Finally, a rate-sensitivity index is introduced to quantify the tested specimens’ rate-sensitive behaviour.

The objective of this work was to investigate the effect and optimization of turning parameters such as spindle speed, feed rate, and depth of cut as well as wood sawdust content on the roughness quality of wood-plastic composites (WPCs). The Box–Behnken design and response surface methodology were used in experiments. Three roughness parameters, namely average roughness (Ra), root mean square average of roughness (Rq), and average maximum height (Rz) were employed to evaluate the surface quality of WPC samples. Based on the findings of the experiments, the Ra, Rq, and Rz values reduced with increasing spindle speed in a range of 430 to 1030 rpm, whereas the values increased when increasing the feed rate in a range of 0.05 to 0.15 mm/min. Also, an increase in depth of cut ranging from 1 to 3 mm and WPCs with a higher amount of wood sawdust in a range of 30 to 50 wt% raised their surface roughness. Finally, optimal conditions for the turning of the WPCs were determined to comprise a spindle speed of 781 rpm, a feed rate of 0.05 mm/min, a depth of cut of 2.8 mm, and wood sawdust content of 30 wt% with the highest desirability score of 1.000. Under such conditions, the sample had Ra, Rq, and Rz values of 1.8, 2.2, and 11.3 µm, respectively. The optimal conditions for turning can be used to effectively process different WPC products into various shapes.

This paper presents numerical modelling of the ballistic impact response of hybrid laminated structures, which are developed through combinations of ceramics, Ultra-High-Molecular-Weight Polyethylene (UHMWPE), Kevlar and compressed wood. It is, for the first time, to embed the compressed wood in the ballistic panel and numerically investigate the impact response of the hybrid structures made of the multiple constituent materials. Different constitutive models and the related failure criteria were employed in the modelling to capture the ballistic responses of the constituent materials and hybrid structures. The numerical simulations were compared with the corresponding experimental results with acceptable correlation. The essential features of the hybrid composite structures subjected to high velocity impact were simulated by the finite element (FE) models, such as deformation and failure modes, back-face signature and the residual velocities. The FE models developed are ready to be used to assist design lightweight composite armour with optimized ballistic resistance and self-weight.

The study aimed to test the hypothesis that biochar's unique properties, such as its microporous structure, can enhance concrete's resilience to high temperatures. Despite expectations of reduced crack formation and enhanced fire resistance, the experimental results revealed a limited impact on concrete's fire behaviour. The investigation involved the use of two biochar types, fine and coarse biochar as replacements for cement and aggregates, respectively. Fine biochar exhibited higher water absorption and Young's modulus than coarse biochar, but both resisted ignition at 35 kW/m² radiative heat flux and had peak heat release rates below 40 kW/m². Incorporating these biochars at varying weight percentages (10, 15, and 20 wt.%) into concrete led to a gradual decline in compressive and tensile strength due to reduced binding ability with increased biochar content. Exposure to 1000 °C compromised mechanical properties across all the samples. However, the biochar concrete maintained compressive strength (compared to the control) with up to 20 wt.% biochar as a fine aggregate substitute after exposure to 600 °C, and as a cement replacement after exposure to 200 °C. This substitution also yielded a significant reduction in CO₂ emissions (50 % reduction as the biochar loading amount doubled) from concrete manufacturing, showcasing biochar's potential for sustainable construction practices. Despite not fully supporting the initial hypothesis, the study demonstrated biochar's viability in reducing carbon footprint while maintaining concrete strength under certain fire conditions.