Applied Mechanics and Materials Vols. 166-169

Abstract: Ping Pong has been considered as one of the most popular sports in the world. Fast break and curving ball technology is this game’s core technology, it will be very important to deeply understand this through biomechanical study. In this research, we based on fast break and curving ball features of kinematic to reveal the table tennis forehand techniques. High speed motion analysis was recorded from eight male subjects. The action was divided into three major phases: back swing, attack and follow through. At the end of back swing stage, break and curl technologies, the speed parameter shows some differences. While the fastest speed in ball contact frame, the speed of curling ball was significantly higher than the fast break. Further study could be carried out in detailing analysis at sub-stage of the action for integral considering.

Abstract: In order to study and improve moment-curvature hysteresis model of reinforced concrete shear walls, experiment of reinforced concrete shear walls was conducted. Based on experiment of reinforced concrete shear walls, moment-curvature relationship is deduced and moment-curvature hysteresis curves are obtained. The existing moment-curvature hysteresis models of reinforced concrete walls are discussed and improved, and the calculated moment-curvature hysteresis curves with the modified model fit well with experimental results.

Abstract: The paper presents studies on numerical modelling of beam-to-column joint behaviour in typical service and exceptional design situations. The complexity of such investigations arises from highly nonlinear effects associated with the prediction of joint performance, such as structural imperfections, large displacements and rotations, inelastic properties of steel and concrete, bonding effects between steel and concrete, and slip between concrete and structural steel, among others. The paper addresses these problems and provides validation of numerical modelling techniques trough comparison with experimental data for joints under hogging and sagging moments.

Abstract: In this paper, we checked the mechanical response of a simple frame structure with and without the existence of interval parameters taken into account. Discovered the differences between the traditional analysis methods of the structure and the analysis methods with the range of parameters taken into account. Gave their own ideas about the mechanical response of the frame structure considering the uncertainties, and provides a reference method for the accurate calculation of the actual structure considering the range of parameters.

Abstract: The field functions of the spline finite point (SFP) method were constructed by the linear combination of B-spline basis function, and the higher-precision results would be obtained with less discrete nodes by the SFP method. In this paper, based on Reddy's third order beam theory, a motion equation was developed by the SFP method to analyze the first five natural frequencies of piezoelectric laminated beam under different axial forces. The influence of second-order effect caused by the axial force on vibration control was discussed based on the modal control theory and the Linear Quadratic Regulator (LQR) optimal control method. It can be concluded that the SFP method is suitable for the dynamic analysis of piezoelectric beam which needs less computational cost and has high accuracy. The vibration of the structure can be effectively inhibited by the LQR method and modal control theory. And the axial force has significant impact on the natural frequencies and control voltage of piezoelectric beam.

Abstract: Multi-way tubes on air conditioning condenser are considered as research objective. The ordinal hydro-forming method and finite element simulation method are utilized to analyze the influence of process force on wall thickness such as internal pressure, axial force ,balance force and their matching relationship. The uniform experimental design method and regression method are utilized to solve the prediction model of wall thickness. The results show that the slope of straight line loading path has a significant effect on branch height, the greater the slope is, and the higher the height is. What’s more, the fold line loading path can effectively improve the branch height while the shock loading path can effectively improve the wall thickness‘s uniformity.

Abstract: Element-free Galerkin method (EFGM) is successfully applied to solve the bending problem of plates on a Winkler foundation. The shape function which is characteristic of high-time continuity is formulated by means of weight function. A way to incorpor- ate the self-adaptive influential radius in weight function is proposed. Based on variational principle, this paper derives control equation for the bending of plates on a Winkler foundation from Mindlin-Reissner plate theory. Using penalty function mothed, assembled stiffness matrix which is real symmetry positive definite matrix is deduced. This method can solve the bending problem of plates with different boundary conditions on a Winkler foundation. The corresponding computer programs of EFGM and post-process programs are also developed. Numerical examples show that EFGM solving the bending of plates on a Winkler found is reasonable and feasible. This present study provides a newly effective numerical method for the Winkler foundation bending problem and expands the application field of EFGM.

Abstract: This paper studies how polymer alters the flexural toughness of concrete. By selecting five different types of polymer mixing into concrete; results indicate that polymer has obvious effect to enhance toughness of concrete evaluated by toughness index T. By crack path prediction analysis, the crack path of polymer-modified concrete is more tortuous and consumes more energy while crack propagation than ordinary concrete.

Abstract: This paper presents experimental and finite element analysis result of a full-size Buckling Restrained Brace (BRB). The brace consists of a steel core encased in a steel tube filled with concrete. The low-cycle fatigue check was incorporated into the cyclic test program. Test results show that the BRB product can develop stable hysteretic responses up to core axial strain of 1.3% and the maximum compressive loads is 1.23 times the actual yield load. The specimen performs well through the whole test sequence. Nonlinear finite element analysis was conducted for a comparison analysis, and contact interactions between the steel core and concrete infill were modeled. The finite element model can reasonably predict the compression behavior and post-yield strength of the specimen.

Abstract: As an important part of hydroelectric power station,wind cover is under a high temperature stress in the process of running the station,and the structure may be in danger.This paper analyze a hydropower turbine wind cover’s temperature stress in two different conditions with large general-purpose finite element analysis software ANSYS.Study shows that in the worst case of load combination,Wind cover appears higher tensile stress values.In order to ensure the structural safety, the measures of arranging ring bar and vertical bar on the outer wall of the wind cover are suggested.