Advanced Materials Research Vols. 291-294

Abstract: A new topology optimization model with holes’ geometric constraints for continuum structure is presented. It is solved by an evolutionary optimization method based on interval relaxation, in which the problem is divided into two subproblems of topology optimization process and size/shape optimization process. The optimal topology of structure can be found gradually by introducing interval relaxation factor to adjust holes’ size constraints, delete noneffective holes and by generating new holes based on the sensitivity analysis of objective function. Interior penalty-function method is employed as an optimization technique for the size/shape optimization of the structure corresponding to the topology. When the holes’ size bounds are the actual values, the optimal solution is the smallest objective function structure in the various topologies. Thus realizes the holes’ geometric size and location design, topology design and layout design together. The optimization results of example shows the method proposed is of good effectiveness and engineering applicability.

Abstract: Introduced the working principle of active magnetic bearing unit and took the electric spindle with 5.5kW for example, finite element analysis of the magnetic fields of radical magnetic bearing was analyzed through finite element analysis by ANSYS software to find out the variation of magnetic field distribution and affecting factors. Analysis results showed that radical magnetic bearing had small leakage magnetic field, the principal axis’ maximum offset from the ideal center line was 0.0025mm and the principal axis had superior radical running accuracy when the circularity of supporting journal on principal axis was 0.003mm, the unilateral air-gap value was 0.3mm while the principal axis suspended normally and the inside track’ circularity of magnetic pole was 0.007mm. It can meet the working requirements of precision machine tool. The research results provided theoretical basis for structural optimization of the active magnetic bearing unit.

Abstract: Minimally invasive robotic surgery has been investigated in various surgical application due to high accuracy, fine manipulation capability, tele-operation. Haptic feedback plays a significant role in MIS. In this paper, a dynamics model of a haptic robot is established, and PID algorithm is proposed. To prove the proposed method, an experimental system has been developed. Simulations and experiments show proposed methods is an effective method to master-slave MIRS.

Abstract: In order to improve the comprehensive performance of concrete truck mixer, considering the kinetics between concrete and blade, a parametric design model is built to find the relation between the parameters of the blade and performance. Based on subdividing function, the drum is divided into different parts called helix, the helix is designed as different blades for each part, then all the blades are combined into a complete helix. According to the design requirements (slump, the bevel angle of the drum), the corresponding blades are created. The simulation and engineering test show that this parametric design model can improve the comprehensive performance, besides, this method provide a new way to solve the detail design problem between multiphase and blade.

Abstract: To solve the problem of piston striking cylinder and pumping insufficiency, an optimization method of concrete open-loop pumping displacement control is derived and presented. In order to control piston stroke effectively, the optimization model of concrete open-loop pumping displacement control parameters is built based on considering the system’s open-loop characteristics. Satisfying the physical constraint of preventing piston striking cylinder and maximizing piston’s effective stroke are taking as the evaluation criterion during the modeling process. Using this method, simulation and experimental research has been proceeded in a type of concrete pump. The result shows that concrete pumping piston can not only meet the noninterference physical constraint, but also increase the pumping efficiency significantly under variable loads. The optimization model provides a new method that can be used in engineering practice for solving the design problem of concrete pumping open-loop control system under variable loads.

Abstract: It is difficult in finite element model(FEM) updating, because the essence is a mechanical anti-question solving. In the paper, the suppositional material method is utilized to model the FEM of a mirror frame system, and the required updating parameters are defined. The functions between the natural frequency and the updating parameters are established based on the response surface method. Based on the response surface model and the modal experiment results, the sum of absolute value of relative errors between the results of experiments and simulations is defined as the optimization objective, four required updating are identified automatically. The first three natural frequencies of updated mirror frame system are better accordant with the experiment results, which proves the method correct and reliable.

Abstract: The nonlinear forced vibration of damped circular sandwich plates is studied. From the movement equations of circular sandwich plate expressed in displacement components, got the relevant nonlinear vibration equation by Galerkin method. The changing of initial deflection, stiffness and a harmonic force which can affect kinetic characteristic of configuration was researched. The FRF of primary resonance periodical solutions were obtained, synchronously modal analysis experiment for composite material plates were tested.

Abstract: Calculations of the end-plate semi-rigid joints are carried out with a FE-program ANSYS. Some results of the calculations are introduced in this paper. The influences of the joints semi-rigidity on the deformation, the bending capacity and the internal force of the structure are researched; the initial rotational stiffness, the elastic ultimate moment and the plastic ultimate moment of the steel joints and the composite joints are compared. Some results may be useful for the design of the end-plate semi-rigid joints.

Abstract: Many new control techniques and energy dissipation systems which can decrease the response of wind vibration and earthquake. But there is less research on the mixed control system of Damper and TMD. In order to improve the shortcomings of Damper system and TMD system, combining their respective advantages reasonably, the mixed control system of Damper and TMD were analyzed in this paper. A 20-storey Benchmark model was used to compare the effects of various control systems under 2-directional earthquake. Taking the displacement reducing coefficient (DRF) as the objective function, Damper system, TMD system, and the mixed control system of Damper and TMD are optimally designed based on Genetic Algorithm (GA). Numerical results show that the mixed control system of dampers and TMD proposed in the paper can work in coordination and complement each other to achieve better control effect.

Abstract: Stess spectrum serves as prerequisite of analysis on fatigue failure, which is the major cause of malignant industrial accident. The dynamic load coefficient is calculated by allowing for dynamic response of steel structure in complete working cycle and regard steel structure and load as a vibraton system of two degrees of freedom. The load date and its statistical characteristic is collected.through observation of 600t-176m gantry crane in some ship-building base. Then based on Monte Carlo method, the load is simulated and loaded on finite element model. Finally the stress spectrum of key parts of structure is calculated.