Advanced Materials Research Vols. 415-417

Abstract: A concrete barrier used on rural highways of China was proposed. The crashworthiness of the concrete barrier was analyzed using the non-linear explicit dynamics FE code LS-DYNA. The finite element models of car, bus and concrete barrier were developed and validated using experimental results. These models can be used to simulate the dynamic collision process and evaluate the performance of the road safety barrier on rural highways. The nonlinear performance of materials as well as the boundary conditions was considered. The results show that the concrete barrier could contain and redirect the car and bus in the collision.

Abstract: This study investigates the effect of moisture content on the bending fatigue properties of T300/914 composite laminates immersed in water for 7 days and 14 days. Displacement-controlled three-point bending fatigue tests were conducted on specimens. After 40,000 cycles the fatigue test was stopped and the properties were measured on the tested specimens. Reduction in material strength was found to depend on the level of moisture content. Experimental results reveal that the moisture content in the laminates increased with immersion time and that moisture absorption accelerated damage propagation in the composite. Hygrothermal ageing lowered the threshold level for the onset of fatigue. The experimental results were further validated by the supportive micrographs that illustrate different moisture content and their morphology before and after moisture absorption.

Abstract: A kind of small sample for implant test was designed for thin-wall components. The notch type and calculation method for test load were determined through theoretical analization that proved to be reasonable by practical test verification.

Abstract: The cyclic deformation including the ratcheting of TA16 titanium alloy was investigated experimentally at room temperature. Experimental results under symmetrical strain-controlled cyclic loading with various strain amplitudes show that the responded stress amplitude keeps almost unchanged with the increasing number of cycles. It is concluded that TA16 titanium alloy can be regarded as a cyclic stable material. Remarkable ratcheting was also observed under asymmetrical stress-controlled cyclic loading, i.e., ratcheting strain increases with the increasing number of cycles. The ratcheting strain strongly depends on the stress level and increases with the increase of applied mean stress, stress amplitude and stress ratio. These findings are useful to reasonably model the cyclic deformation of TA16 titanium alloy.

Abstract: Silicon-hydrogen crystalline models are proposed to estimate theoretical hydrogen storage capacity in porous silicon media with nanostructure features like cubic nodules, columnar forests and thin wall honeycomb like networks. To simulate these nanostructure features and their hydrogen storage capacities, three basic crystalline types (cubic, column and plate) have been developed as building blocks for constructing H-Si weight storage models under the assumption of that hydrogen is chemically bonded to available surface silicon atoms. Using these models, the hydrogen weight storage capacity for all feature dimensions from unit to infinitely long can be estimated. According to these theoretical models, the best nanostructure for hydrogen storage is cubic nodule, columnar forest and thin wall network in that order. They have weight storage capacity limits of 5.77%, 5.21% and 2.78% respectively for infinitely large feature dimensions.

Abstract: In view of comprehensive evaluation of the Three-Proof performance for modern aircraft, and based on the damage mechanism of heat and humidity, salt air, and mildew, the comprehensive evaluation index system is established. The weight of each evaluation index is determined with mathematical statistics method and the operations research theory. The comprehensive evaluation model for aircraft Three-Proof performance under the influence of multi-factors is established by using the technology of multi-index comprehensive evaluation synthesis. Through normalized and standardized processing of the data, the Three-Proof performance comprehensive evaluation was carried out on several kinds of typical aircraft in our country. The evaluation result is reasonable, which confirms the credibility of the model as well as the method.

Abstract: The influence of crosslink agents on properties of modified-NRs was investigated. The results prove that the presence of oxirane rings and/or chlorine atoms on the ENR and CENR molecules prominently affects on overall studied properties of the vulcanized rubbers. Crosslink agents also play significant role on Mooney viscosity, curing and tensile properties of the vulcanized rubbers, however, they are less influence on dynamic mechanical and thermal properties.

Abstract: Different laid modes of aluminum alloy section bars and their mortise and tenon joints were bending tested, and their mechanical properties were compared, in order to research on the influence that forming a mortise and tenon joint brought to the original bars. Opening a hole laterally and inserting another shorter bar in the hole changed the bending properties and energy absorption capacity of the original bar. In horizontal laid mode, the mortise and tenon joint was weaker than the original bar when bearing bending load, but it was stronger in vertical laid mode. Weld beads of the mortise and tenon joints were strong enough to maintain the structure integrality before the main section bars were destroyed by load.

Abstract: A new tubular cathode support for Direct Ethanol Fuel Cell (DEFC) was prepared by the gelcasting process using mesocarbon microbead(MCMB) and graphite as the main raw materials. The effects of different graphite doping ratios on tensile strength, bending strength, crushing strength, volume resistivity and shrinkage rate for the prepared tubular cathode support were studied by experimental test. The result showed that the prepared tubular cathode support had very good comprehensive performance. The tubular cathode support with 10% graphite exhibits the best performance such as bending strength 25MPa and resistivity30µΩ•m, and it satisfied the DEFC cathode working conditions and performance requirements.