Applied Mechanics and Materials Vols. 66-68

Abstract: The microstructure of high-entropy Alloys AlFeCuCoNiCrTix (x=0, 05, 1.0) with different titanium contents had been studied. The results showed that: (1) The microstructure of AlFeCuCoNiCrTix exhibited the trend from dendritic structure to eutectic-cell structure as the titanium contents increasing and spinodal decomposition, nanoprecipitation and amorphous phase can be also observed; (2) Composition segregation appeared (especially Cu) and Ti promoted the segregation of Cu; (3) Alloys was consisted of FCC and BCC, and phases gradually converted from FCC+BCC1 to FCC+BCC1+BCC2 with addition of titanium and BCC2 became the leading phase; (4) Both ordering and spinodal decomposition coincided due to the difference of atomic size and high entropy effect.

Abstract: Focus on the topography features of V-shaped deep river valley in Ada dam area, the influence of intensively, moderately and slightly weathered stratum as well as the action of river valley erosion on geostress field was considered. Then, the 3-D initial geostress unloading model was established based on the measured geostress data and geological conditions. Combining the finite element numerical method and inversion theory, multiple regression analysis was established between the measured and corresponding calculated results of geostress. Then, the optimal regression coefficient could be derived. In addition, for convenience of comparison, another method was adopted by ignoring the action of river valley erosion. Through the comparison between the computed values by two methods and the measured geostress values respectively, it is found that the computed values by the former method are more close to the measured ones. Therefore, the distribution rule of initial geostress field can be obtained accurately, which provides important reference for design and construction of Ada dam and its diversion tunnel layout.

Abstract: In this paper the surface of wood/polyethylene (PE) composites were treated by liquid oxidation, and the structure of surface for wood/polyethylene composites before and after treatment was characterized by contact angle, fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM); combined with bonding strength test, the effect of concentration for handling solution and addition of oxidant on bonding properties of wood/polyethylene composites was also investigated. The results showed that the contact angle of surface for wood/polyethylene composites reduced and the surface wettability had been improved after liquid oxidation; the -C-O- and C=O functional groups were formed on the treated surface and the surface roughness increased; meanwhile, the shear bonding strength for the treated sample increased significantly after treatment. And these changes would be more obvious when enhancing the concentration of handling solution and adding oxidant.

Abstract: The surface of wood/polyethylene (PE) composites was treated by low-pressure glow discharge of air plasma to improve its adhesion properties. And the changes on the surface properties of the treated composites under different discharge time were studied by contact angle, AFM and FTIR analysis. To determine the effect of plasma treatment on the adhesion of the composites, shear bond strength tests were conducted. The results showed that the contact angle decreased gradually with the increasing of discharge time. The roughness of plasma treated samples increased. The FTIR analysis results showed that the polar groups such as -OH, -C=O and -O-C=O were formed on the surface of the composites treated under plasma. The data of shear bond strength analysis also showed that the adhesion strength of composites increased remarkably after plasma treatment, and the durability of bonding joint under water and heat environments also be improved.

Abstract: The paper researched on the globoidal indexing cam, and established the parameter design system based on VC++ Object-Oriented method and Pro/E secondary development, which can guide user to complete the data input with the friendly interface. It made synthesis of the mechanism and generation of the cam profile automatic. The system is proximate, easy to operate and adjust. Then the assembly model was built under the circumstance of Pro/ENGINEER directly. And meanwhile the movement of the mechanism was simulated and the interference was checked so that we can certify the design. This is a new method for the mechanism's deep research and extensive application.

Abstract: This paper has designed the T-channel, the fish-tail channel and the coat-hanger channel, and compared them separately. The conclusion has been obtained, which the coat-hanger channel conforms to the production technological requirement of melt-blown nonwoven fabric. In order to further confirm the coat-hanger channel design, the pressure and speed distribution of flow process which polymer melt flow in the channel have been simulated by ANSYS. The results indicated that the coat-hanger die channel conformed to the design requirement perfectly.

Abstract: A two degrees of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction of brake disk and pads is built firstly, the numerical method is taken to study the impacts of stiffness on automobile brake groan. The calculation result shows that the variation of stiffness and has different influence on automobile brake groan. So the brake groan could be controlled through the adjustment of the relevant parameters according to the real vibration state of brake disk and pads.

Abstract: A one degree of freedom nonlinear dynamics model of self-excited vibration induced by dry-friction was built firstly, the numerical method was taken to study the impacts of structure parameters on self-excited vibration. The calculation result shows that the variation of stiffness can change the vibration amplitude and frequency of the self-excited vibration, but can not eliminate it, Along with the increase of system damping the self-excite vibration has the weakened trend and there a ritical damping, when damping is greater than it the self-excite vibration will be disappeared.

Abstract: In order to study the ground vibrations induced by high-speed train passing on viaduct, two FEM sub-models, the train-bridge-pier model and the pile foundation-soil model, are established by means of the software of ANSYS. The effectiveness of the numerical models is tested and verified by comparing with other existed results. Moreover, the influences of different train speed and the damping ratio of soil on ground vibration are analyzed.

Abstract: The paper introduced a computer-aided industrial design system: Forklift Truck’s Multi Plan Optimizaion System, and demonstrated the modules’ function and techniques with examples. Considering the requirements for efficiency and precision in the forklift styling, the author developed the forklift optimizing software for its styling, which includes parameter optimization, color optimization and part combination three modules. The parameter optimization module can vary the user defined parameters of the forklift models and generate new models. Color optimization module can group the model surfaces and render the groups with different color. New color plans are generated through random changing of the colors in each group. The parts combination module divides forklift into several parts and build lib for each part. The module can pick parts from the lib and assemble them into a whole forklift and demonstrate them. The thesis developed a proto system on the Solidworks platform with VBA programming tools. Interactive genetic algorithms are applied to realize the three module’s function.