Applied Mechanics and Materials Vol. 487

Abstract: The high performance algorithm for supercomputer simulation of magnetic nanoparticles arrays was elaborated and implemented in parallel c++ code. Our program package allows a modeling of magnetic hysteresis phenomenon in the system of the magnetic spherical monoaxial one-domain dipole nanoparticles fixed in node of a square lattice with the period of 10^-8 m in frame of Stoner-Wolfforth approach. During numerical experiments dependences of a type of curves of a hysteresis on number of particles and values of a critical field are investigated. It was showed, that the area of loops has proportional dependence from individual critical field of nanoparticles.

Abstract: According to the surface formation mechanism of elliptical vibration cutting (EVC), EVC process and three dimensional cutting surfaces are analyzed in this paper. The model of EVC surface topography is established based on curved surface remove function under the assumption that the tool edge is sharp enough. Simulation analysis of surface topography is conducted to verify the established model. The present research clarifies the law that cutting parameters influent on EVC surface topography. Whats more, it provides some references for optimizing the selection of EVC cutting parameters and further improving EVC surface quality.

Abstract: Because we did not consider the dynamic characteristics of system components in static voltage stability analysis, the reliability of the static analysis of the results is reduced. So if we want to explain the mechanism of the voltage instability fundamentally, we must adopt the method of the dynamic analysis. This paper discuss the small disturbance analysis method and the continuation algorithm analysis method of the dynamic analysis method, then research the mechanism of voltage collapse and the results of the dynamic analysis. A load model and the dynamic system for the voltage stability studies is the key of the voltage stability to the maturity.

Abstract: Self-loosening is one of the major failure reasons for bolted joints. Utilizing the finite element method, a 3-Dimension finite element model under dynamic shear loading is built to study the loosening of bolted fastener phenomenon. And the effect of increment step length, initial clamping force, amplitude of the shear load, thread tolerance, friction coefficients on the loosening process are studied.

Abstract: Since the fast response of the internal structure of the Electrorheological (ER) suspension fluids occurs in the controlled space (electrode distance is generally 1-2 mm) of the applied electric field, where the main feature of the ER suspension fluids in the certain time and spatial scales is low shear rate but high flow resistance, which means the Mach number and the Reynolds number are generally small, it can be researched as micro-scale flow. According to this characteristic, the author proposed a discrete-particle-motion model of the ER suspension flows based on the Lattice Boltzmann method(LBM) of the Mesoscopic kinetic theory. The results of the dynamic simulation showed that the model solved the problem of describing the changes of the rheological properties of some local flow fields and the influences on the particle movement during the two-way coupling in this flow field.

Abstract: The mechanism of using prestressed carbon fiber reinforced plastics (Pre-CFRP) sheet to strengthen reinforced concrete beams with anti-arch deflection method was proposed. And then the corresponding theoretical analysis was derived, and the effectiveness of this reinforcement method is verified by experiment in laboratory to improve the girders stiffness and cracking load.

Abstract: In order to make the paralyzed live on their own and return to the society to the most degree, mechanical exoskeleton technology is tried to applied in the field of auxiliary equipment. First, degrees of freedom and mechanical structure at the each joint of lower extremity exoskeleton was ascertained.Then a three dimensional modeling design for the lower extremity exoskeleton was carried out with SIEMENS NX8.0 and a walking gait on a flat for it was planned on MATLAB basing on inverted pendulum model.Finally the legs model was simulated on ADAMS.The result of the simulation was basically the same as planned gait which can better satisfy the requirement of human walking and can be used as reference for developping the physical prototype of lower extremity exoskeleton.

Abstract: Analysis of Flexible Body is a difficult problem in system dynamics analysis. In the paper, the basic theory of ADAMS flexible body and some methods of adding flexible bodies to a model are introduced. And build a system simulation model. Through manipulator grasping tomatoes examples verify the effectiveness of ADAMS flexible body grasp simulation, provide stress and elastic deformation data basis for manipulator grasping flexible body.

Abstract: The force load research of disc cutter can be used in the design of disc cutter, in order to improve the working life, determine when to change another cutter. Based on the working platform of ABAQUS finite element analysis module, single disc cutter rock-breaking of the simulation model is established, and according to the theory of rocks plastic rule, dynamics analysis and dynamic simulation are done when the cutter is in rock-breaking process by which, the added force can be got when the disc cutter and rocks contact each other in different wear conditions of contact force in the process of the dynamic contact each other. The results show that with the cutter damage increasing, the added force is increased and cutters maximum instantaneous stress load is 1.5 ~ 2.5 times than the average stress load, which has a negative influence on working efficiency. To have a clear understand of cutters design and working life and when to change another cutter in working time, the results also offer an engineering parameters for researching the load state of TBM tunneling.

Abstract: Pressure pipelines have been applied widely in the chemical industry, the petroleum enterprises and the electrical power plants. Leakage and explosion accidents happened frequently owing to the weakness of the pressure pipeline. To monitoring the pressure pipeline weakness, a novel method is presented by using optical FBG (FBG: Fiber Bragg Grating) sensors to carry on the real-time monitoring of the pressure piping surface strains. A typical pressure pipeline was fabricated with weak position of L shaped, Tee shaped and U shaped joints. The strains of the weak position were analyzed by the ANSYS software, and then the same weak positions were monitored by experimental method of FBG sensor. The FBG sensor was verified a feasible means to monitoring the pressure pipeline by comparing the ANSYS software results with the experimental results of FBG sensors.