Applied Mechanics and Materials Vols. 215-216

Abstract: Central cavity in the workpiece of cross wedge rolling is a high-level product defect which would seriously weaken the strength of material. Based on the three-dimensional elastic-plastic finite element analysis method, numerical simulation of cross wedge rolling parts with minute central cavities was performed. The area changes of the minute central cavities were obtained, and combined with the internal stress state during the rolling process, the viewpoint that tensile stress in the three-dimensional directions is one factor that leads to cavity growth was expound.

Abstract: Using UG to build a shell of the three-dimensional solid model, using the finite element software on the solid floor is analyzed, the shells fall into 8 drop, respectively, to various forms of stress and strain were compared, and the shells of the reliability analysis.

Abstract: Cement anchor pegs have been used in acetabular cup fixation. This paper analysed various designs of cement anchor pegs using the finite element method. The design parameters have been investigated including the diameter, length, position and chamfer of the cement anchor pegs. It was found that introducing a chamfer to the cement anchor pegs would reduce the maximum stress by 25 percent in the cement mentle. The analysis in this paper provides the foundations further work to be carried out including a detailed model of bone and cement interfaces.

Abstract: Due to the pressure difference between the restrictor’s internal and external, the restrictor’s performance comes under the influence of deformation in practical use. The analysis method combines the air lubrication analysis and structural FEM. The thickness, modulus of elasticity, fixation method of the porous restrictor was analyzed. The result illustrated that: the load capacity increases and stiffness decreases when the modulus of elasticity or thickness decreases. When the edges, annulus and center of the plate are fixed at the same time, the restrictor has the same load capacity and stiffness as that the deformation is neglected.

Abstract: Dynamic stall is an aerodynamic phenomenon that may occur when an airfoil is subjected to rapid, cyclical changes in angle of attack with respect to the incident ambient flow. This phenomenon can often produce repeated and significant changes in lift and moment coefficients within very short time frames, which manifest as severe and rapid changes in structural loads. Rotorcraft such as helicopters and wind turbines are particularly susceptible to dynamic stall, which is a highly undesirable operating condition. The condition plays a part in limiting the forward speed of a helicopter whilst also producing cyclical loads that accelerate fatigue. The structural issues are more severe for wind turbines, where blade spans approaching seventy to eighty metres are becoming common. Research into techniques for reducing the severity of the undesirable effects of dynamic stall is often conducting in laboratory environments using wind tunnels as the main investigative tool. The required cyclical changes in angle of attack are achieved by using machines that oscillate the test airfoil about an axis parallel to the span of the wing. Such mechanisms can be powered electrically, mechanically, pneumatically or hydraulically, and have various combinations of complexity, advantages and disadvantages. The current work describes the design process of an electrically powered dynamical stall test rig. The use of CAD / CAM to assist in the performing of design calculations and a comparison of the rig with other mechanisms is presented.

Abstract: The finite element modes of composite columns were built. The nonlinear analysis of the common steel column and the partial concrete encased steel composite columns were conducted. The load-displacement curves were getting. The strength of partial concrete encased steel Strengthened columns was much higher than the common steel column. Finally, Construction design suggestions and theory study of the type of partial concrete encased steel composite columns are advanced according to the results of analysis and computer simulation.

Abstract: with the speed rising of railway train and the weight lightening of car-body, the frequency range of car-body is widened and the natural frequency is decreased. Especially, the local modes of car-body are caused by suspension device under the car-body bottom, which lead to large vibration response, influence the ride comfort and fatigue failure of structure. In this paper, the whole mode of car-body was analyzed through finite element software. The local mode of car-body bottom and side wall were computed by method of equivalent stiffness constrain. The results show that the local mode of car-body is mainly caused by asymmetry suspension device. The modal analysis method and local modal analysis method adopted in this essay provide the reference and guide the dynamic structural design.

Abstract: In engineering design, according to not considering past experience information; hence, to make structure parameters for achieving high confidence level, much data for traditional reliability-based robust design must be adequately collected, analyzed, and tested. However, in practical engineering, it is very difficult for doing much test, only for getting in the form of finite test samples. Under the conditions, it has much difficult for the traditional reliability-based robust design. In the article, we present a new reliability-based robust design method that solves the form of incomplete information. The method adopts a Bayesian inference technique to estimate reliability, gives definition of Bayesian reliability. In the research, the mechanical parts bayesian reliability-based robust design mathematical model is established and the bayesian reliability-based robust design approach is presented. The numerical results illustrates the method presented is an efficient and practical reliability-based robust design approach.

Abstract: Introduced the conventional failure criterion of the precision of motion of mechanism and the analytical methods of reliability, and then focused on fuzzy failure criterion of precision, advanced mechanism fuzzy reliability formulas, and illuminated the application of this method.

Abstract: Introduced a transmission system of a new oscillation buoy ocean wave energy generation device, the system can transform the mechanical energy into electric energy. A pair of gear model was built by SOLIDWORKS, the parameter is just the same as the real data, then imported the model into ADAMS. Under the same simulation parameters, two experiments were done, one engaged without failure, the other engaged with one broken tooth of drive wheels. Calculated TIME and STEPS by Shannon sampling theorem, simulated the marker point’s acceleration of the drive gear, then obtain image data of time domain and frequency domain, after analyzed, found this method has a significant meaning to practice.