Applied Mechanics and Materials Vol. 607

Abstract: Engineered Material Arresting System (EMAS) is a new type of soft ground arresting system that can safely arrest the overrun aircraft in an allowed distance without injuring aircraft passengers and damaging aircraft landing gear. The paper provides an overview of the EMAS background firstly. A numerical simulation is carried out by VB.NET software through reasonable hypothesis and simplification the system of dynamic model. The model is reasonable and feasible compared with prototype experiment results.

Abstract: Enhancement of fuel consumption and transmission efficiency needs a continuous improved variator performance in continuously variable transmission (CVT). This paper focuses on the improvement of a slip controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using model for variator dynamic in the CVT. The slip control purpose is to improve the performance of variator and to increase the efficiency of CVT by determination the line pressure which generates the clamping force. The selection of slip reference-point is taken at the transition region between the micro and macro slip region to guarantee the maximum variator efficiency. The adaptive fuzzy logic control (FLC) and Linear Quadratic Regulator (LQR) controllers are applied to control the clamping force. The proposed control systems are designed to ensure the existence of a slip values within the region, which has the traction coefficient maximum value, while the load disturbances caused by suddenly changed torques in the drive lines. These approaches have potential for the CVT efficiency improvement, as compared to PID controller. The adaptive fuzzy logic control technique uses a simple group of membership functions and rules to achieve the desired control requirements of slip in CVT. Simulation results show that satisfactory slip improvement is achieved together with good robustness against suddenly changed torques. It is further revealed that all adaptive fuzzy logic control and LQR controller have a valuable effect on minimizing the slip amount and maximize the variator efficiency

Abstract: Safety membrane is a good mechanical device that can be applied in middle and small hydropower stations instead of a surge tank. This present study deals with the determination of three most important parameters of safety membrane, rupture pressure, diameter, and number. The mathematical model of transient process is established by introducing the method of characteristic, which is used for the simulation of the rupture behavior of safety membrane. Then the model is applied to a specific hydropower station that only can employ safety membrane as the regulating measurement, and it shows good performance. The achievements of the study can serve as a reference for similar projects.

Abstract: Particleboard jointing during screw fixing activities weakens the furniture, kitchen and household joinery. Screw jointing on the particleboard surface contribute to the particleboard fracture. Fracture on the particleboard surface will promote failure in jointing. This study was done to determine the effect of applying different style of screw insertion technique on fracture and fatigue failure. Three different style of screw insertion technique applied was self-drilling, pilot-hole and pilot-hole with countersunk (P+CSK) insertion technique. From the study, applications of P+CSK screw insertion technique caused highest number of damages. 57% of common chipboard screw samples were damaged when P+CSK screw insertion technique was used. Most fracture failure is the type 6 mode. There is no significance difference in number of damages for self-drilling insertion technique and pilot-hole insertion technique. Therefore, self-drilling insertion technique, which is the insertion technique used by kitchen cabinet installer was preferable due to the ease of handling during screw insertion.

Abstract: Based on double trailing arm suspension, relating to two-wheel-drive structures with inhibition of vertical vibration: a motor-integrated electric wheel-drive system and an electric wheel-drive system of which the motor can swing up and down and act as a dynamic absorber. In the paper a unified differential equation of motion of the two electric wheel drive systems was deduced, and Matlab and Adams were applied to simulate and analyze the ride comfort of the two drive systems. The analysis results show that compared to the traditional In-Wheel Motor Driven EV, the vertical acceleration of the car body of either of the two drive systems is lower, which significantly increases the ride comfort of car. Between the two electric wheel-drive systems, the latter system with dynamic absorber motor is more efficient to inhibit vertical vibration.

Abstract: The working principle of a new kind of double-acting pneumatic-hydraulic pressure amplifier having two-step output pressure driven by the pneumatic cylinder with rodless piston is introduced. The output flux and the output pressure calculating formulae are also given out. Compared with the known single-acting pressure amplifier,the innovative pressure-amplifier is simple in structure and has much higher working efficiency. It can also output adaptive two-step liquid pressure, which is similar with the hydraulic differential connection, thus it is easy to realize move quickly in low pressure and move slowly at high pressure. This system also fits a trend of green manufacturing for using green air as transmission medium and with closed oil without leak to output pressure liquid.

Abstract: Standpipe is a connection between surge chamber and tunnel, which can greatly reduce the quantities. This present study deals with how to take the influence of standpipe into consideration and what extent is the influence. The mathematical model of standpipe is established by introducing the method of characteristic. Then the model is applied in one pumped storage power station with long standpipe of 67m. Results show that the standpipe has great influence on whatever tank surge or pressure. And with the increasing standpipe length, the upsurge and minimum draft tube pressure present downtrend. The influence of standpipe in tailrace surge chamber should be considered in design phase. The achievements of the study can serve as a reference for similar projects.

Abstract: Through the establishment of motor electromechanical coupling vibration model, torsional vibration characteristics of motor is analyzed in starting process. With 1000T lubricating oil ship electric propulsion shafting as the object of study, the free vibration and the forced vibration characteristics are analyzed. In two cases of considering the electromagnetic excitation torque and without considering the electromagnetic excitation torque, the responded vibration of electric propulsion shafting is calculated. The low noise design of the motor and propulsion shafting provides a theoretical basis.

Abstract: This paper presents a design of mini actuator without using permanent magnet for auto-focus (AF) compact camera module (CCM) built on mobile phone, tablet PC and notebook. The current through the coils of electromagnets will yield magnetic force to move the moving part up and down. Comparing with conventional spring-type voice coil motor (VCM) and non-spring type VCM, the proposed actuator eliminates the concerns of rare earth supply and magnetic flux leakage which can fail the function of magnetic flux sensitive device such as e-compass. The proposed actuator also simplifies the power converter design from bipolar scheme as required by conventional non-spring type VCM to unipolar. A comprehensive electromagnetic analysis is performed by using finite element method to characterize the performance of the proposed actuator. Numerical simulations demonstrate that the magnetic flux leakage in the proposed actuator is much smaller than those by conventional design.

Abstract: From the calculation method of natural frequency of single-rotor system whirling vibration, this article puts forward corresponding dynamic equations. Several modeling of single-rotor system are established, with different numbers of shaft elements, relative number of degrees of freedom, four types of modeling the shaft and disk interface. Error and accuracy of natural frequency are analyzed with modeling properties. The above all mentioned results make it possible to summary influence characteristics of modeling for rotor system.