Applied Mechanics and Materials Vols. 365-366

Abstract: Influences of whey protein isolate (WPI), sodium caseinate (NaCas) and soybean protein isolate (SPI) on gelatin (GA) film properties were investigated by comparing with common plastic films. The results suggested that WPI and NaCas caused tensile strength (TS) of GA film increasing from 6.38MPa to 7.17MPa,7.52MPa; water vapor permeability (WVP) decreasing from 18.46*10^-13g m^-1 s^-1 Pa^-1 to 17.92*10^-13g m^-1 s^-1,16.46*10^-13g m^-1 s^-1; and resulted in oxygen transmission rate (O₂TR) decreasing from 128.315cm³m^-2d^-10.1MPa^-1 to 37.352 cm³m^-2d^-10.1MPa^-1, 38.129 cm³m^-2d^-10.1MPa^-1.WVP of GA films increased 13.2% and O₂TR decreased 4.1% as the addition of SPI. NaCas-GA composite films was the optimal group which had significant advantage on Ts, optical properties and barrier properties.

Abstract: Twisting has an influence on not only the strength, luster, softness, and elasticity of the yarns, but also the properties of the resulting fabrics. This study aims to evaluate how the rotor twister speed and the thermal treatment temperature influence the properties of the polyethylene terephthalate (PET) plied yarns and wrap yarns. Both yarn types are made with a twist coefficient of 1, 1.5, or 2, and then thermally treated in an oven at 70, 110, and 150 °C. The resulting plied yarns are wrap yarns are tested for tensile strength and elongation, and their surface is also observed by a stereomicroscope to determine the influences of the two parameters. The results of the experiment show that twist coefficient does not influence the tensile strength nor the elongation. The tensile strength of various plied yarns and wrap yarns is approximately 4.4cN/dtex; the variation in the twist coefficients is too small and thus hardly causes any significant differences in the yarns properties.

Abstract: Chitosan (CS) and gelatin (G) both have good biocompatibility and biodegradation, qualifying them for use in tissue engineering. In this study, CS and G are blended with different ratios to make the mixture solution, and then freeze-dried to form three-dimensional porous CS/G bone scaffolds. The surface, cross-section, porosity, and pore size of the resulting bone scaffolds are observed and analyzed. According to the experimental results, the addition of gelatin gives the CS/G bone scaffolds morphology with few pores. As can be seen from SEM observation, there are linear pores in the cross-section. In addition, with a larger quantity of gelatin, the CS/G bone scaffolds have a lower porosity.

Abstract: The micromechanical properties of a Al alloy/SiC hollow sphere syntactic foams composite material have been studied using the Solidwork simulation code applied the finite element method (FEM). The simulated results have shown that the values of quasi-static compressive strength, plateau stress, and densification strain are 175 MPa, 120 MPa and 0.50, respectively. The general trend of dynamic stress–strain graphs is similar to quasi-static compression graphs. The compressive properties of the composite are not strain rate sensitive. The simulated peak strength value is ≈140 MPa. Al matrix and SiC hollow sphere exhibit different mechanical behaviour. The ultimate stress is found near the interface of composites. The failure initiates by the fracture of weak particles, some of the cracks can propagate to the matrix as well. Shear band formation in the matrix and shearing of SiC_hs lead to the major failure activity.

Abstract: Interpenetrating phase composites (IPCs) are becoming an important class of materials as the result of the development of a number of new techniques for producing composites with interpenetrating microstructures. In this paper, the mechanical properties of a B₄C-ZrB₂/Al IPCs have been studied using the Solidwork simulation code applied the finite element method (FEM). The results have shown that the B₄C-ZrB₂ ceramic matrix and Al network exhibit different mechanical behaviour. The ultimate stress is found near the interface of the composites. Simulated data shows ultimate tensile strengths of up to 453 MPa at a failure strain of up to 0.5%. The compression strength was up to 615 MPa with 0.41% compressive strain to failure. The composites show an excellent resistance to high cycle fatigue. Fatigue life for specimen was 5.1×10⁴ cycles for 210 MPa while R =-1.0, and 5.6×10⁴ cycles for 133 MPa while R=-0.05. Infiltrated Al addition was the leading reason for the fracture toughness improvement of the composites. The simulated results are consistent with the experimental results well.

Abstract: Calcium phosphate bone cement (CPC), a bioceramic, is commonly used in artificial bone scaffold for impaired bones. In this study, CPC is mixed with polylactide (PLA) fibers and porogenic agent to form CPC/PLA composite bone scaffold. The compressive strength of the resulting bone scaffolds is evaluated and the fractured cross-section is observed by a scanning electron microscope (SEM), thereby determining the influence of fiber length. The experimental results show that the shorter the fiber is, the greater the compressive strength is.

Abstract: The compound fabrics comprised of double layers of nonwovens and carbon fabrics were prepared by needle-punching and thermal bonding techniques. The thermal bonding and number of layers effect on thermal insulating and sound absorbing property have been discussed. The resulting compound fabrics have thermal conductivity decreases to 0.02 W/(m*K) for single layer of thermo-bonded compound fabrics and sound-absorbing coefficient reaches to 0.848 at 4000 Hz for 3-layer un-thermo-bonded fabrics .

Abstract: The dynamic puncture resistance of multi-layer integrated composite which was comprised of glass fabric reinforcement or Kevlar fabric reinforcement and nonwovens were discussed as related to recycled Kevlar fibers amount, number of layer and K-ply position for purpose of cost reduction and performance improvement. The result shows that, 20 wt% Kevlar fibers contained in nonwovens have the optimum puncture resistance. And the dynamic puncture force increases linearly with number of layers, and also improves proportionally as increasing number of K-ply. The resultant multi-layer composite is expected to be used as body armor interlayer and packaging materials.

Abstract: Technical development and rapid telecommunication create convenient consumer products, but produce electromagnetic radiation that hurts the human body, which makes the development of antistatic and electromagnetic-wave-resistant textiles important. This study combines polylactic acid (PLA) fibers and low melting point polylactic (LPLA) fibers by needle punching to make PLA nonwoven fabrics. The lamination layer number is then changed to explore its influence on the mechanical properties of the PLA nonwoven fabrics. Next, the nonwoven fabrics are spray-coated with polyaniline (PANI) to form the PANI/PLA nonwoven fabrics. The PANI/PLA nonwoven fabric with a lamination layer number of 5 has the optimum tensile and tear strength. A coating of PANI can reduce the surface resistivity.

Abstract: The effect of Kevlar fibers amount, number of layers, thermal bonding and fabric type on constant-rate puncture resistance of low-cost compound fabrics are discussed. Therein, compound fabrics were prepared by nonwovens and woven fabric via needle-punching and thermal bonding processes. The result shows that, Kevlar fibers amount and number of layers are both positive to improvement of puncture resistance. And thermal bonding process increases the wearer safety of puncture-resistance materials. For different kinds of fabrics, compound Kevlar fabric shows the maximum puncture resistance.