Applied Mechanics and Materials Vols. 101-102

Abstract: The adhesion and the compressibility of the soft soil will vary as the earth gravity changes. In this study, the pressure-sinkage characteristics in low gravity conditions were investigated by three-dimensional Discrete Element Method (DEM). The data of the DEM parameters were obtained by analyzing the pressure-sinkage relationship embedded in laboratory testing data. The pressure-sinkage experiments of the sample soil in different gravities were simulated by using the software PFC3D. Using the Bekker formula, the values of pressure-sinkage parameters were obtained. The results show that, when the earth gravity changes from one sixth of the standard earth gravity to the standard earth gravity, the sinkage exponent increases lineally. The cohesive module of deformation increases along the conic trend. The low gravities have a sensitive affect on the data of the frictional module of deformation, and the data distribute beside a line. The change laws of the pressure-sinkage parameters provide instructions for the optimization design of vehicles working in low gravity field planet.

Abstract: The thrust cylinder is one of the most important components in thrust system of the shield machine. The enormous thrust force and radial load makes the cylinder work under bad environment. In this paper, it uses nonlinear finite element method to simulate the thrust cylinder structure of a type shield machine. From the simulation results, the contact stress distribution of the oil cylinder guide sleeve and the deformation of the piston rod are discussed, and then the way to reduce the stress concentration is proposed. It provides the theory basis for the design and check of the thrust cylinder.

Abstract: In order to develop an automated segmentation system for jacquard fabric images, a new approach based on MRMRF algorithm with variable weighing parameter is proposed in this paper. Firstly the variable weighting parameter different to the one in traditional MRMRF is described, which can provide a more accurate vector. The next step is MAP estimation and the model for texture segmentation. During this iterative process the initial value is big enough to learn more accurate parameters of feature energy. With the iterative number going on, the value will decrease and stop decreasing when the iterative number comes to some degree. Lastly the experiment results show that the new approach works better than the traditional method with constant weighing parameter.

Abstract: The motion equation of boom system of pump truck carrying concrete flow is set up based on the coupled vibration theory of cantilevered pipe and the finite element theory. Dynamic stress history of boom system with parameters of dip angle α=0°is simulated combining MATLAB simulation analyses with ANSYS finite element model. The feasibility of this method is verified through field experiment. Stress histories are simulated by adjusting parameter of dip angle as follows: α=20°,52°and 80°.Great stress points are painted on the Goodman Fatigue Limit Diagram measured by experiment. And then fatigue strength assessment of boom system is done. The research method can be used for the design calculation of similar products.

Abstract: The rigid-flex coupled multi-body dynamic model of Motoman HP20 was built in this paper. The parts geometry shapes were modeled in 3D modeling software and imported into the multi-body platform. Then the joints were added to the parts. The arms were analyzed in FE software and modal neutral files were obtained. Then rigid parts were replaced by the modal neutral files. Driven curves of each arm joint were obtained by D-H method. The modal analysis of system was also made to analyze the robot dynamic characters. The results give some suggestions for robot motor selection and structural dynamic optimization.

Abstract: A research program is currently underway with the purpose of developing a double-layer air jet looms with solo-supported gas device. Issues related to the design and feasibility analysis of the solo-supported high pressure gas device are discussed. The results of simulations show that assistant nozzle is necessary during weft insertion motion, but too many assistant nozzles would cause the flow velocity reduce. And it is confirmed that flow channel with one main and four assistant nozzles is one of the best designs to keep the flow velocity at the middle line of flow channel more than 90m/s and make the loom work swimmingly.

Abstract: A novel structure of a six-wheel all-terrain mobile robot with the integration of active and passive control is presented in this paper. According to different complex terrain environments, three-dimensional simulation models of the six-wheel all-terrain mobile robot were built using ADAMS software and the dynamic simulation analyses under different terrain conditions were accomplished. Using the ADAMS model, the kinematic and dynamic characteristics curves of the whole robot and parts of robot were obtained. The simulation analyses provide the theoretical basis for the optimization of the mechanical structure, control system design and the selection of drive motors. Simulation results show that the structure of this kind of robot has good mobility and obstacle-climbing performance.

Abstract: The temperature is a key factor that affects the metal deformation and the material property in the rolling process. The metal deformation is often carried along with the variety of temperature. Moreover, the plastic work is converted into the thermal energy during the process of the metal deformation. Therefore, the numerical simulation of the rolling process should take the temperature factors into consideration to improve the prediction accuracy. In this paper, we use the full three-dimensional Rigid-plastic finite element method to predict the temperature distribution which relate to linear or non-linear boundary condition of the free surface. Based on the simulation, the impact of radiant heat-transfer coefficient on the temperature prediction can be obtained. The comparison of the calculated results between the linear and non-linear boundary conditions demonstrates that the temperature obtained on the linear boundary condition has higher accurateness than that obtained on the non-linear boundary condition.

Abstract: In this paper, Taguchi experimental design method is applied, and injection molding CAE simulation analysis is conducted. Influence factors of warpage of products are analyzed. According to the results of ranking, influence factors of warpag are the packing pressure, packing time, melt temperature and mold temperature. The packing pressure is the most important influence factor. To get the best level combination of various factors, mixed level orthogonal experimental design is applied to the optimization. Optimal levels of combination process parameters are obtained and the quality of injection products is greatly improved.

Abstract: Multidisciplinary design optimization of a biaxial capacitive micro-accelerometer with the crab-leg flexural suspension is discussed. Considering the influence of microstructure design, fabrication process and detection circuit, as well as the constraints of fabrication limitations, damp design and adhesion factor, a multidisciplinary optimization model is developed by global criterion method. Furthermore, genetic algorithm is applied to obtain the multi-objective optimum of the proposed multidisciplinary design model.