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The general two-dimensional (2D) woven laminated composite (GWLC) is widely used in aviation, aerospace and high speed railways, and its superior specific stiffness and strength substantially reduce the weight of the structural components. However, when the GWLC is damaged by flexural, shear and impact loads, the layers are prone to delamination. To improve the interlayer properties of the GWLC, a loop warp yarn is added to the plain fabric by means of three-dimensional (3D) weaving technology, resulting in a double-side-loop fabric with Z-directional fibers. This paper investigates the double-notched shear (DNS) properties, in-plane shear properties, and flexural properties of GWLC and a new double-side-loop 2D woven laminated composite (DWLC). The test results verify that adding the loop warp yarns can greatly improve the interlayer properties of the general 2D woven laminated composites. The DWLC increases the interlaminar shear strength by 81.5%, the in-plane shear strength by 49.4%, and the flexural strength and modulus by 90.2% and 61.4%, respectively. The excellent mechanical properties of the DWLC lay a foundation for loop fabrics in engineering applications. [ABSTRACT FROM AUTHOR]

Carbon fiber paper reinforced thermoplastics (CPT) have broad application prospects because of its simple production process and good mechanical properties. Currently, polyamide 6 (PA6) is a promising matrix for CPT and is widely used for mass-production. However, the performance of CPT materials in marine and harsh environments must be evaluated because of its environmental sensitivity. In this study, the seawater absorption of CPT was analyzed using Fick's diffusion law. The flexural properties of CPT in harsh and marine environments were studied by three-point bending. Based on the results, it was concluded that seawater and high temperatures have negative effects on the flexural properties of CPT. Microscopy results showed the mechanisms of failure under the action of seawater and high temperatures. Droplet test was employed to analyze the interfacial shear properties between the fiber and resin. The results showed that after seawater immersion, the interfacial shear strength had a discernable decrease. [ABSTRACT FROM AUTHOR]

Carbon fiber paper–reinforced thermoplastics (CPTs) are widely used because of their formability and superior mechanical properties. Polyamide 6 (PA6) is used as a resin matrix in carbon fiber-reinforced composites owing to its good mechanical properties and adhesion with the carbon fibers. However, PA6 tends to absorb moisture because of the presence of hydrophilic groups in the polymer backbone. This may negatively affect the mechanical and interfacial properties and reduce the service life of CPTs products. Therefore, this research focuses on the long-term applicability of CPTs in aqueous environments. In this study, CPT plates were fabricated by compression molding and subjected to long-term aging in a hydrothermal environment, and the effects of long-term aging on the properties of the composite were investigated. The water absorption behavior was found to follow Fick's diffusion law, the interfacial property was determined by the microdroplet test, the surface morphology was analyzed by 3D laser scanning microscopy, the physicochemical properties were determined by differential scanning calorimetry and Fourier transform infrared spectroscopy, and the flexural properties were determined by the three-point bending test. A modified rule of mixture and the Kelly–Tyson model were applied to describe the changes in the flexural properties. The findings of this study provide guidance for the further application of CPTs products. [ABSTRACT FROM AUTHOR]

To improve the applications of beetle elytron plates (BEPs, which are biomimetic sandwich plates inspired by beetle elytra), the flexural performance and its synergistic mechanism of multibody molded BEPs were investigated via cantilever testing and finite element method (FEM). The results are summarized as follows. (1) Although debonding damage causes failure of the multibody molded BEPs and honeycomb plate and the reasonable range of trabecular size for BEPs is narrow, both the optimal loading capacity per mass and failure deformation of the BEPs are over two times those of the honeycomb plate. (2) A flexural synergistic mechanism is revealed in the trabecular-honeycomb core structure of BEPs; this mechanism causes the maximum deformation of core structure to gradually transfer from the honeycomb wall to the trabeculae with the increase in η (the ratio of the trabecular radius to the distance between the center points of two trabeculae), which means the different stretching behaviors in these core structures. (3) Unlike the compressive mechanism of BEPs, by controlling and balancing the deformation degrees of the trabeculae and honeycomb walls, the flexural mechanism achieves a minimum core deformation and an optimal flexural performance. These results suggest a qualitative relationship between the deformation behavior of trabecular-honeycomb core structure and bending performance of the whole BEP, and provide a solid foundation for subsequent research and the considerable application potential of this biomimetic sandwich structure in many fields. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced thermoplastics (CFRTP) show relatively high mechanical properties and are expected to be feasible materials for mass production of light-weight structures. In particular, discontinuous CFRTP (DCFRTP) with affordable resins have been developed to realize excellent formability and mechanical properties. Currently, polyamide 6 (PA6) is a promising matrix for CFRTP in mass-produced automobiles. However, due to the hygroscopic and viscoelastic properties of polyamide resins, the influence of water absorption on the mechanical properties of CFRTP under varying temperature is necessary to be investigated. In this study, the influence of water absorption on the mechanical properties of discontinuous CF/PA6 composites was investigated. Chopped carbon fiber tape reinforced thermoplastics (CTT), which are randomly oriented strand (ROS) composites, were selected as DCFRTP. The mechanical properties of the composites were investigated by a three point bending test between −40 and 125 °C, as a function of water absorption. The flexural modulus were calculated using the Timoshenko beam equation to predict degradation by water absorption. The mechanical properties of CTT have a relatively high sensitivity to water absorption. [ABSTRACT FROM AUTHOR]

The steady increase in production of corn based ethanol fuel has dramatically increased the supply of its major co-product known as distiller’s dried grain with solubles (DDGS). Large amount of DDGS and corn flour are used as an animal feed. The elusieve process can separate DDGS or corn flour into two fractions: DDGS fraction with enhanced protein and oil content or corn flour fraction with high starch content, and hull fiber. This study investigated the feasibility of using fiber from DDGS and corn grain as alternative fillers to wood fiber in high density polyethylene (HDPE) composites made with two different sources of polymers. Two fiber loading rates of 30 and 50% were evaluated for fiber from DDGS, corn, and oak wood (control) to assess changes in various physical and mechanical properties of the composite materials. Two HDPE polymers, a bio-based HDPE made from sugarcane (Braskem), and a petroleum based HDPE (Marlex) were also compared as substrates. The biobased polymer composites with DDGS and corn fibers showed significantly lower water absorption than the Marlex composite samples. The Braskem composite with 30% DDGS fiber loading showed the highest impact resistance (80 J/m) among all the samples. The flexural properties showed no significant difference between the two HDPE composites. [ABSTRACT FROM AUTHOR]

Two kinds of 2.5D deep straight-joint structure ultra-high molecular weight polyethylene (UHMWPE) (twisted and original) fibers woven fabric reinforced epoxy resin composites were prepared by the hand lay-up method. Subsequently, the flexural property, microstructures, and failure mechanisms of the composites were also investigated. The average flexural strength of 2.5D deep bend-joint structure twisted fiber and original fiber woven fabric composites were 176.66 MPa and 204.45 MPa, respectively. The results of the characteristics indicated that the twist was the main factor which affected the flexural performance. Flexural property vitally relied on the strength of the fiber itself. Twist decreased the strength of the yarns, which meant that when the mechanical property of woven fabric reinforced composites was improved, the yarns must be kept straight in the woven fabric. The study are extremely valuable to guide the improvement of the mechanical property of the woven fabric reinforced composites. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE) fiber/epoxy composites were fabricated by a vacuum assisted resin infused (VARI) processing technology. The curing condition of composites was at a cure temperature of 80 °C for 3h in a drying oven. The characteristics of 2.5D (shallow bend-joint and deep straight-joint) structure and 3D orthogonal structure were compared. The failure behavior, flexural strength, and microstructures of both composites were investigated. It was found that the flexural property was closely related to undulation angle θ. The flexural strength of 3D orthogonal structure composite was superior to the other two structures composites with the same weave parameters and resin. [ABSTRACT FROM AUTHOR]

The growing ethanol production around the world demands more value-added applications for its main byproduct, distillers grains. The present work reports the study of using corn based distillers dried grains (DDG) as biofillers for biobased epoxy resin and the mechanical, physical and thermal properties of the composites. The biobased epoxy resin is the blend of diglycidylether of bisphenol-A based resin and epoxidized soybean oil. The incorporation of DDG into the biobased resin accelerated the curing process as evident from the differential scanning calorimetry and temperature-modulated Fourier transform infrared spectroscopy. The 40 wt% DDG filled composite showed an excellent retention of flexural strength of up to 94 % of that of the neat epoxy. Furthermore, the composite filled with the DDG treated with epoxy functionalized oligomeric silsesquioxane showed even better flexural properties thanks to the improved wettability of the biobased resin with the filler. Dynamic mechanical analysis showed a 12 % increment in storage modulus for the surface-treated DDG composites over the biobased resin. The improved interfacial adhesion between the DDG and matrix through the surface modification was also observed in the morphological characterization with electron microscope. The study demonstrates the viability of combining DDG biofiller with the epoxy bioresin to produce novel biomaterials at low cost. [ABSTRACT FROM AUTHOR]

In this paper, acrylonitrile-butadiene-styrene (ABS) nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nano-clay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix. [ABSTRACT FROM AUTHOR]

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Pre-tensioned construction material is utilized in engineering applications of high strength demands. The purpose of this study was to evaluate the effect of the pre-tensioning fibers of fiber-reinforced composite (FRC) using three-dimensional finite element (FE) analysis. The 3D FE models of particulate composite resin (CR), FRC and composite resin reinforced with pre-tensioned fibers (PRE-T-FRC) were constructed. The uniaxial three-point bending test was simulated using FE analysis to calculate the principal stress distribution. In the FRC and PRE-T-FRC, stresses were higher than CR, and they were located in the fiber. However, the maximum principal stress value at the composite of PRE-T-FRC was lower than the FRC and CR. Composite resin reinforced with pre-tensioned fibers was advantageous for stress distribution and lowering the stress at the composite itself. Experimental studies on physical properties of pre-tensioned FRC are encouraged to be conducted. [ABSTRACT FROM AUTHOR]