Applied Mechanics and Materials Vols. 121-126

Abstract: By dint of nonlinear mechanics theory and method, and based on rock creep characters, do some analysis to the model of rock mechanics, so we can get conclusions and stability about rock system’s stationary state under the action of uniaxial compress. It has some directed senses to the underground rock project under mining effects.

Abstract: Molded pulp material has been paid much attention for the cushioning package, yet there is no perfect method for evaluate the cushioning properties of different molded pulp configurations, which hampers the advance of molded pulp industry. In this paper an Equivalent Area Theory are put forward in order to study the cushioning properties of this material and the molded pulp pallet is taken as practical example. By experimental and theoretical analyses, the cushion coefficient and maximum stress curve of the molded pulp pallet is obtained, and a design method of molded pulp pallet is established.

Abstract: With the help of electron backscatter diffraction (EBSD ) and orientation distribution function (ODF) analysis, experiments of the different batch annealing were conducted to give an study of recrystallization and texture of Cold-rolling Low Carbon sheet steel based on CSP , and the relationship between initial isothermal temperature and drawing properties has been investigated. The recrystallization soon finished the grains during annealing produce relatively strong {111} and {111} texture，at this temperature region as the initial isothermal temperature, the double isothermal cover annealing process design, enabling access to a strong favorable texture and uniform pancake grains, and the proper temperature is the key control factor level.

Abstract: Molecular dynamics simulation has been employed to investigate the adsorption behavior of glutamic acid and aspartic acid on Cu (001) surface, and the inhibition mechanism was also discussed. The results indicated that the two corrosion inhibitors could both adsorb on the Cu surface firmly due to the interaction between polar groups and surface. The two inhibitors both have excellent corrosion inhibition performance. However, the inhibition performance of glutamic acid is better than aspartic acid.

Abstract: The microstructures of 11 kinds of commercial steels quenched from high temperature were deeply studied by optical microscope and canning election microscope. It was proved that packet martensite in medium and high carbon steels is not lath martensite, but rather packet plate martensite. Through the analysis of crystallography，it was found that four change rules of crystal orientation may arise during the process of martensite transformation. Two inner interfaces spontaneously formed were only discovered in martensite transformation process: small-angel boundary (misorientation angle is 0 ~ 10º) and twin boundary (misorientation angle is 70º32’). The former mainly appeared in low carbon martensite, and the latter principally formed in medium and high carbon martensite. The twin boundary packet mechanism in medium and high carbon steels has made in detail in this paper.

Abstract: The inverter-fed traction motor is one of the key components in the locomotive. However, the motor insulation failures have repeatedly occurred in premature. The failure mechanism for insulation under continuous impulses is different from that under sine waves. The single stress approach in design stage and also in ageing studies offers relative simplicity, but it is inapplicable to real life operating conditions which mostly are of multi-stress type. In this paper, a novel test apparatus of insulation failure time was designed for accelerating aging test. Meanwhile, electrical breakdown experiments on magnet wire insulating polyimide film (FCR 100) used in the inter-turn insulation of JD117 inverter-fed motor was conducted. The effects of multi-stress including impulse amplitude-temperature and impulse frequency-temperature were investigated respectively. The test results under different conditions were analyzed based on statistic analysis of Weibull distribution. Finally, insulation life models under combined thermal and electrical stresses were proposed using the multi-stress approach. A fitted formula for ageing life was presented which had two independent variables of voltage and temperature. The generality of the model lies in the fact that it can be used for designing of insulation system of all electrical components containing solid insulating materials surrounded by gas. Since the model is based on the probability of insulation deterioration under the action of the stresses applied, that gives us the opportunity to calculate the life time of insulation system for given system of stresses, the materials selected and the requested probability of failureless system operation.

Abstract: To satisfy the requirements of rapidity, stability and accuracy in positioning of pump-control electro-hydraulic servo system, the paper designs a multi-mode extension control switcher, which can realize switchover between different control modes and give full play to each control mode to meet the requirements of control system for various performances. In order to apply this method to practice, the principle, the control algorithm process and part program segments of multi-mode extension control realized by Mitsubishi PLC was introduced, and experiments was done to verify the control effect. The result shows that multi-mode extension control of pump-control electro-hydraulic servo system using PLC can satisfy the demands of control system.

Abstract: An optimum process for a two-step press forging of stepped holes in a metal sheet was proposed .Numerical simulation on the two-step process was carried out by using DEFORM-3D. Distributions of effective strain and effective stress were obtained. The study showed that the process not only can form the stepped, but also can increase the surface quality and strength of stepped holes in sheet metal parts, According to the numerical simulation’s process parameter , an experimental die was designed, the simulation results were in good agreement with the experimental data

Abstract: The numerical simulations of mold filling and solidification process for the A380 aluminum alloy were done by the supposed mathematical model. The casting defects in the process of mold filling and solidification were predicted by the result of the casting simulation. The casting defects of simulation are well compared with the practice. Some measures presented were improved for the existing technological process.

Abstract: For the bolts on the experiment table, there are two main kinds of forces, namely, shear force and tensile force. This paper will test these two different forces that the bolts received, verifying their compliance with the service life. Finding out which situation is better by comparing the safety coefficient under the static load and the fatigue life under the fatigue load. And then put forward some reasonable measures for improving to make the bolts meet the fatigue life of the experiment platform.