Applied Mechanics and Materials Vols. 556-562

Abstract: Build a three-dimensional model of BTA deep hole drilling, simulation the static characteristic of the three-dimensional model using Ansys simulation software,observed the wear condition of the BTA drilling teeth, middle teeth and side teeth in the Experiment,verify the results of simulation,providing a basis for the BTA drilling structural optimization.

Abstract: In order to fulfill the requirements of docking successfully, a scheme of step-by-step docking is proposed, the implementation methods to realize initial connection and accurate docking are given, the preliminary docking mechanism of a double flexible manipulator is designed, a testing system for RP flexible manipulator is established, corresponding experimental prototype is developed, and the mechanical model for relevant flexible regulation is made up to do experimental study. The result shows that the established RP flexible system can well satisfy the requirements of initial connection in the step-by-step docking, thus proves the feasibility of the proposed scheme.

Abstract: The theory of orthogonal test provides a new design idea for the design of muffler with complicated structure. The second baffle plate position, outlet pipe perforation rate, connecting pipe diameter and perforation rate of a heavy vehicle exhaust muffler are chosen as the level factors. The sum of the transmission loss in the frequency range from 510Hz to 640Hz is chosen as the evaluation index. Based on the orthogonal test theory, GT-POWER software is used to analyze the evaluation index under different level factors. According to the orthogonal analysis table, optimization of the internal structure for the muffler is carried out. The optimized results show that attenuation performance of the optimized muffler in the optimized band is superior to the original muffler and the frequency bands allowing noise to pass through is significantly reduced.

Abstract: Based on time precise integration method, an improved precise integration method, which called, is studied in the paper to solve the dynamic equation of , where v is an unknown n dimensions vector, Hv and f are respectively the linear homogeneous part and nonlinear part on the right end of equation. Then the calculation expressions of the method are given. The numerical example of nonlinear dynamic analysis of low pressure rotor of high parameter turbine shows that the proposed method is no need to solve the H ^-1 and the computational accuracy and efficiency can be ensured.

Abstract: To discover the interaction rules between the cutterhead of shield machine and the soils, the model experiment of shield machine tunneling is performed, and the particle discrete element model of the experiment is built. By adjusting the particle parameters, the simulated cutterhead torque is compatible with the experiment observed results. Then the displacement of soils in the front of the cutterhead, behind the cutterhead, and in the front of the chamber board is obtained. The soils in the front of the cutterhead try to flow into the nearest opening. However, the soils behind the cutterhead move toward the wall of out barrel. The movement of soils in front of the chamber board is in accordance with the rotation direction of the cutterhead.

Abstract: Base on clinching process, an air-hydraulic intensifier clinching devices was designed. In order to accurately control the quality of clinching, the displacement sensor and pressure sensor were joined in the control loop. So two different control feedback loops were founded. With two different ways of clinching tests, a clinching test method was founded, and the joint strength is analyzed. The result was that the shears strength and fracture strength in different directions of clinching samples are different.

Abstract: The interaction between vibration and friction exists widely in the mechanical system. In order to research the effect of the vibration amplitude on the contact point friction in the mechanical system, a new apparatus is developed independently to measure the point contact friction influenced by the changing amplitude. The data acquired through the apparatus show that the friction at the contact point decreases with increasing of the amplitude. In terms of theoretical analysis in this paper, the increasing of the amplitude actually reduces the contact area at the point. In addition, the friction at the contact point is proportional to the contact area. So, the friction decreases with the decreasing contact area caused by the increasing amplitude.

Abstract: The mechanical fit between the connecting rod's small end and the bush is a typical interference fit. In this paper, an elastic-plastic finite element model of the assembly of the connecting rod and the bush is built based on ABAQUS simulation platform and simulation experiments are carried out by adopting the method of design of experiments. The magnitude of interference and the thickness of the bush are set as the test factors and the maximum radial deformation of the connecting rod’s small end hole, the radial contact pressure between the connecting rod and the bush, the plastic deformation of the bush and the fatigue strength safety coefficient of the connecting rod small end are set as the response variables. Based on the response surface equations, the multi-objective optimal approximate mathematical model is set up and the Pareto optimal set are gained and discussed.

Abstract: The most critical issue of the blanket module remote maintenance operation is to remove or replace the heavy module with high positioning accuracy of 1mm. Located in vacuum vessel (VV) of the nuclear fusion device, the blanket module is weight up to 500kg, thus the grasp and installation of blanket module come to be the essential problem during the maintenance operation. To meet the requirement, we propose a new hierarchical control strategy of rough and fine positioning technology based on combined sensors. The detail procedures and implementation of the control scheme has been carried out successfully on Virtual Robot Experiment Platform to demonstrate the feasibility of the control strategy.

Abstract: A new 3-DOF parallel mechanism is presented and its kinematics analysis model was established based on the vector method. Based on the speed equations of the mechanism, its singular conditions and singular configurations were analyzed systematically. Moreover, a given mechanism’s singularity was simulated by using cylindrical coordinate search method based on its inverse displacement solutions. The results show that the workspace of mechanism with outset chains is much bigger than mechanism with inset chains. The analysis and simulation on singularity provide a theoretical basis for the dimension synthesis and optimization of this kind of parallel mechanism.