Applied Mechanics and Materials Vol. 367

Abstract: This paper proposed a finite element formulation to analysis the vibration of couple-stress continuum. A four-node discrete couple-stress element relaxed the requirement of C₁ continuity is developed. This element is modified by a bubble function, based on the classical four-ode Lagrange element. The element includes the internal bending constants and the internal initial moment of rotation. Numerical examples show that the present FE scheme is accurate for the eigenvalue analysis of couple-stress continuum structures, especially for the low order frequency analysis.

Abstract: The purpose of this paper is to introduce a new design of CPM training machine of recovery for knee joints which provides a constant-speed, translational and steady recover environment. A parallelogram mechanism and a magnetorheological fluid mechanism are used to ensure the patients not only to perform passive train in the earlier period after operation but also do active train in different stages without the influence of gravity compensation. The training machine makes the recover motion meet the physiology need of the joint motion after operation and has the applicable significance in medical practice.

Abstract: The paper describes and compares selected failure and plasticity conditions of concrete. The CEB-FIB condition, the von Mises plasticity condition with modification for concrete and the Chen-Chen condition are studied. The conditions are compared in 2D and two of these conditions are also used for numerical analysis of a deep beam. The software BSA is chosen for the analysis in the paper. The software BSA is based on the finite element method.

Abstract: This paper presents a study to investigate response of adjustable speed drives due to voltage sags. A small ASD of 0.39 kW, 50/60 Hz, and 400-480 V was used for testing how drives will respond to voltage sag types; A, B, C and D. The drive response is influenced by sag magnitude, sag duration and phase angle shift. Behavior of the diodes rectifier for conducting is influenced by sag magnitude and phase angle shift represented by sag of types C and D. The diodes rectifiers are reverse biased when it was supplied by voltage sags. Even though there are no charging currents to dc bus capacitor during voltage sags, the drives did not directly trip to certain sag magnitude and sag duration. Sensitivity of the ASD to voltage sag types is presented in voltage tolerance curve. Sag of type A produces highest sensitivity on the ASD and it trips for sag magnitude of 62.5% and 250 milliseconds in duration.

Abstract: Recently, micro-inverter has received great attention due to its excellent performance under local shade condition. However, this kind of inverter needs large DC-DC voltage gain to implement grid-connected power generation for single photovoltaic module. This paper presented a new single switch high voltage gain DC-DC converter, which is consist of a double output voltage Boost converter and a flyback converter. The outputs of both converters are connected in series to supply power for the load, so the proposed converter has high voltage gain. Moreover, the input circuit is shared by the boost converter and the flyback converter in this new converter, which facilitates the converter structure and improves the converter efficiency by recycling the transformer leakage energy. The double output voltage boost converter can reduce the turn ratio of the flyback transformer and it can decrease the leakage inductance of transformer and diode voltage stress. In addition, the clamp capacitor can limit the power device voltage stress and simplify the circuit design. The paper analysis the operation process of presented converter and gives the detailed deduction of relevant formula to guide the converter design. Experimental results verify the presented converter.

Abstract: This paper presents the design of PID controller and State-Feedback controller with integral action to control the position of DC motor.PID controller is tuned using Ziegler-Nichol’s rules. State-Feedback controller is designed by determining the state feedback gain matrix using Ackermann’s formula. The aim of this paper is to compare the time domain characteristics of system response between PID controller and State feedback Controller with integral action. The Simulation results are demonstrated using MATLAB.Graphical User Interface (GUI) is developed for both the controllers. According to the Simulation result, State-Feedback controller with integral action has the better performance in terms of peak overshoot and settling time as compared to PID controller.

Abstract: The paper aims to underline the importance of applying complete optimal control to electric drives, in particular to Permanent Magnet Synchronous Motor (PMSM). The proposed optimal control has three components: the feedback componentassures energy minimization; the forcing component assures the zero steady state; the feedforward compensating component assures fast compensation of the disturbance. The methodology of obtaining this type of the advanced optimal control is based on variational calculus. The solution is a nonrecursive one, avoiding memorizing it from the final time to the initial time, as in the recursive case. Moreover, the solution is orientated to numerical implementation by using a zero order hold in order to solve adequately the matrix Riccati differential equation (MRDE). The practical implication of using the proposed method is the on-line computing possibility of the optimal control solution. The influences of the control weighted matrix upon the manipulated variable of the PMSM electric drive are shown by numerical simulation.

Abstract: This paper proposes a single-phase nine-level Hybrid Cascaded Multilevel Inverter (HCMLI) for Proton Exchange Membrane (PEM) fuel cell with a novel pulse width-modulated (PWM) technique. This technique employs multiple reference signals and a single triangular carrier wave which is used to generate PWM pulses. The inverter offers much less total harmonic distortion and can operate at near-unity power factor. Its performance has been verified based on Total Harmonic Distortion using MATLAB/SIMULINK.

Abstract: In this paper, investigation on starter solenoid to develop a generalized model based simulation methodology to simulate contact bounce characteristics and tuning of the parameters to reduce or eliminate the contact bounce in existing solenoids complying with all functional and cost constraints. Using the measured data, a generalized model based simulation methodology is built using Matlab Simulink to establish contact bouncing characteristics, which is highly non-linear in nature, under various conditions/parametric variations like electromagnetic force, air gap, hard stops, spring rate and mass. The simulation model reveals that the contact bounce is reduced to zero when the stiffness of the spindle spring is in the range of 1050 N/m to 1250 N/m. Thus we can conclude that the methodology adopted helps in understanding the characteristics of existing solenoids and providing practical suggestions for potential feasible modifications that can be incorporated in the existing solenoids so as to tune their physical system parameters for an optimum response.

Abstract: Based on the application of the single-phase electric energy meter, selected the STC11F52XE microcontroller of STC micro technology company and energy measurement chip CS5460A of Cirrus Logic as the controller, sampled the user's voltage and current by time-sharing sampling with the multi-channel analog switch, controlling the ON/OFF of the electric energy of multi-user with the bidirectional holding magnetic relay, design a prepayment electric energy meter with multi-functional for Multi-user based on GPRS communication technology. This meter achieves the electric energy meter standard with one-level.