Applied Mechanics and Materials Vols. 249-250

Abstract: Friction stir welding (FSW) technology requires a meticulous understanding of the process and consequent mechanical properties of the welds in order to be used in the production of high performance components. This paper deals with an experimental campaign aimed at the evaluation of the mechanical properties of AA6061-T6 friction stir welded joints. The joints are obtained by varying the welding parameters, namely, tool rotating speed and feed rate. The non-threaded tool is made of hot work die steel H13. The quality of the joints is evaluated in terms of both hardness and tensile strength. Moreover, for going a step further to study and control welding heat input in FSW process, a piezoelectric load cell is installed between the fixture table and the machine tool workbench in order to measure the welding forces in different directions.

Abstract: Hasofer-Lind method was applied to reliability design of cylindrical shell with internal pressure. The respective reliability design thickness of different diameter ratio was obtained in the case and compared with the thickness by the second moment reliability design method. The results showed that the wall thickness of cylindrical shell with internal pressure is the thinnest by using Hasofer-Lind method. And it is closest to the wall thickness of the second moment method in which the performance function was defined as the difference in actual wall thickness and the wall thickness needed for cylindrical shell with internal pressure.

Abstract: Statistical energy analysis(SEA) method has many advantages in analysis of high frequency, high modal density and complex dynamic systems. Dividing high-speed train cab into a series of sub-systems, the SEA model of high-speed train cab was established. The factors affecting the cab noise, such as modal density, damping loss factors, coupling loss factors, were gotten by theoretical analysis combined with experiments. Using large eddy simulation method, the fluctuation pressures from train head surface were calculated. Using fluctuation pressure as excitation source, wind noise spectra and power flow of sub-systems in cab were obtained, which provided the basis for the control of high-speed train cab noise.

Abstract: A kinematic model of mobile-cylinder engine is suggested. Analysis of motion equation solutions reveals periodic pulsations of rotational frequency in the system which leads to non-uniform rotation of a crank shaft. The amplitude and pulsation phase depend essentially on geometric and kinematic parameters of the model. Discussed are possible ways of the model optimization so as to damp the amplitude of rotational frequency pulsations.

Abstract: With the increasing demand of the consistency on li-ion batteries, to be more stable and consistency for the holding force upon the battery’s charging by the electrode tab-clamps during the battery forming process becomes the basic requirements. This paper offers a new method to test the holding force of a spring clips by using a membrane-type force-sensitive resistive sensor as sensing element. According to the experiment and analysises, this paper also shows the linear fitting on the Pressure-Resistance Characteristic Curve of the sensor, which is close to the actual situation, and provides a basis for the follow-up data processing of the testing system. Multi-groups analysis of experimental data indicates that it is a simple and feasible method to test the holding force of the spring clips using in li-ion battery charging and discharging.

Abstract: In this paper, the average equations are given through using the multi-scale approach method. By using the Melinkov function, the nonsingular linear transformation and the Poincaré map, the sufficient condition for existence of periodic solution of the nonlinear dynamical system about the FGM subjected to aero-thermal load is derived.

Abstract: This paper presents a residual stress prediction model for high-speed machining using the finite element method in conjunction with neural network. The finite element method is utilized to simulate a chip formation process, which is constituted step by step from the workpiece removal process under the conditions of high-speed machining. The residual stress distributions underneath the machined surface of the workpiece are determined subsequently. The artificial neural network is in turn applied to synthesize the data calculated from the finite element method and a prediction model for residual stress distributions within the machined subsurface of the workpiece is thus constructed. The model can predict the residual stress distributions at different locations beneath the machined surface of the workpiece for various workpiece materials under different combinations of cutting conditions such as cutting speed, feed rate, rake angle and edge radius of the tool more effectively.

Abstract: The accurate information of road friction coefficient allows the control algorithm in vehicle activity system to adapt to external driving conditions. This paper developed a slip-slope friction coefficient estimation method based on Unscented Particle Filter. A 7-DOF non-linear vehicle dynamic model was established. The normal force of tire was approximately calculated from the vehicle dynamic model; the slip and longitudinal force of tire were estimated through a combination of tire mechanical model and UPF(Unscented Particle Filter) method. Finally slip-slopes of different adhesion level roads was obtained. Through virtual test environment in ADAMS/Car, the estimation method proposed was verified to be effective and reliable under various road condition. From the method the relationships between the slip-slope and road friction coefficient are achieved.

Abstract: A wheel hub is a key rotor component of automobile. Nowadays alloy wheel hubs are used more and more widely. They are typically lighter for the same strength and provide better heat conduction. As we know that do a FEA (finite element analysis) is necessary before and after the alloy wheel hubs have been made. In this paper, a detail analysis was done with FEM (finite element method), and the stress distribution of wheel hub we got was consistent with the real distribution. Also the FEA results show that the maximum stress is much less the yield stress and the working safety factor is less than the allowed safety factor and it is useful for further work such as fatigue life prediction and reliability assessment.

Abstract: The deformation field and stress states of special orthotropic piezoelectric plate are analyzed. Based on elastic theory, the refined equations of bending thick plate are derived by using Elliott-Lodge’s general solution and Lur’e method without ad hoc assumptions. At first, expressions were obtained for all the displacements and stress components of a piezoelectric plate. Based on boundary conditions, the refined equations for the plate with anti-symmetrical transverse surface loading are obtained.