Applied Mechanics and Materials Vol. 697

Abstract: We designed a type of pilot-operated self-sustaining time delay power on/off circuit which consists of a duplex switch, time delay circuit and a dual-coil, dual-contact electromagnetic logic control relay. We also depicted a dual-coil, dual-contact electromagnetic relay logic control circuit diagram dedicated to this design. Structures and specific couplings of the circuit were presented and analyzed. Functional analysis was also carried out for a variety of work processes performed on the circuit at static or dynamic state, and the results showed that the circuit, in addition to fulfilling its primary function for time delay shutdown of the main circuit, is also capable of automatically powering-off the control circuit and the control power supply when the device is left unattended. This design greatly meets the needs of current time delay control technology, and thus has a great commercial potential.

Abstract: Aiming at the deficiencies of traditional PID control algorithm, the application of Fuzzy PID control algorithm is proposed in variable frequency speed regulation system of glass edge grinding machine. The design of fuzzy PID controller is presented in the paper. The paper not only introduces the system principle and models for inverter and AC asynchronous motor but also tells the principle of Fuzzy PID Controller and its design method. A simulation model including traditional PID Controller and Fuzzy PID Controller is established in MATLAB/Simulink. Through the analysis of the difference between the two controlling outputs, the better performance of Fuzzy PID Controller in response speed, accuracy and stability is proved effectively. The result can be used as important criterion to the practical application of Fuzzy PID control algorithm.

Abstract: Currently, there are less online monitoring forecast methods about running condition and fatigue life of mechanical parts, and the current methods have higher false alarm rate. To solve this problem, danger theory of artificial immune system were introduced into condition monitoring methods. An algorithm to predicting the using state or fatigue life of mechanical part was proposed. In this algorithm, the definition and the generation of danger signals are proposed combined with fatigue life and reliability of mechanical parts. According to the results of simulation and experiment, the theoretically residual fatigue life and reliability calculated from simulation analysis kept accordance with the actual residual fatigue life and the real reliability. This verified the validity of this algorithm proposed in this paper.

Abstract: A vibro-impact dynamic model of a typical single-stage spur gear train has been proposed in this study. The lumped parameter dynamic model includes the constant meshing stiffnesses, the linear time-invariant viscous damping values and the gear clearance (backlash) non-linearity allowing teeth separations. With taking account of the effect on impact of gear tooth when meshing, the dynamic equations of motion are solved for the steady period response by use of analytical method under given periodic motion conditions. The feasibility of the given periodic motion conditions is demonstrated by comparing the analytical results with that of numeric simulation method. A Poincaré map of the system is established. The stability and bifurcation of the system are studied using analytical methods. Finally, the theoretical analyses are verified using numerical simulation.

Abstract: With the application of LED display, traditional manual insertion is unable to meet market demand. LED auto-insert machine solve the problems in manual insertion, such as workforce shortage, low efficiency, high error rate and so on. Based on depth study of LED insertion technology, a new automatic transfer system have been successfully developed in this project, which solve the problems of auto-sorting, polarity detecting, rotation adjusting and position adjusting. Compared with the existing transfer system, the new auto-transfer system improve the system accuracy and reliability, reduce the cost of research, and realize automatic transmission with high speed and high precision.

Abstract: In this paper, authors made contrast with the three finite element methods in analysis accuracy and usability .Those are all based on the structural analysis of mining excavator arm. The first fem is using UG solid modeling capabilities to create model .The finite element model is generated by UG_ANSYS, including setting the loads of material properties and boundary conditions ,also loading work. The process is called preprocessing completely .Then export a“. inp” file,after that, imported that file directly into ANSYS software for solving. The second one is to import solid mode created in UG into ANSYS software directly ,then take pretreatment and solution accordingly.The last one is using UG modeling and UG NX NASTRAN (the finite element analysis function) for structure analysis. It is concluded that using UG completely pretreatment of ANSYS analysis method and UG NX NASTRAN method feel more convenient to operate it with the high analyze accuracy,with the two methods , designers can modify mining mechanical arm weak positions more easily.In turns,they can improve the designing level of physical prototyping.

Abstract: In order to research the thermomechanical behavior of multidisc friction pairs system, three dimensional model is established for numerical simulation under simulated braking process. Based on some accurate boundary conditions, the temperature fields and thermal stress fields of friction discs and separator discs are simulated using finite element method. The temperature fields and contact stress fields of friction disc and separator discs are obtained, and their regularities of distribution are studied spatially and historically. To verify the simulation results, an experimental investigation is carried out. The results offered references for analyzing failure forms and causes of the wet multidisc friction pairs system.

Abstract: The piezoelectric field and structure field of piezoelectric resonator of ultrasonic motor are intercoupling. It is difficult to obtain the solution under some circumstances because of the complex stress boundary condition and the influence of coupling effect. An electro-mechanical coupling finite-element dynamic equation is established on the basis of the Hamilton’s Principle about piezoceramic and elastomer. The equation is decoupled through the shock excitation of the piezoelectric resonator and the piezoelectricity element and material provided by finite-element analysis. As a result, an admittance curve as well as the distribution status of the nodal DOF is obtained, which provides an effective method to solve electro-mechanical coupling problems.

Abstract: Hydraulic technology is one of the key techniques of modern transmission and control. Closed type hydraulic power transmission system is weight ratio, fast action, easy to realize the advantages of flexible stepless speed regulation, flexible power transmission. In this paper, the closed hydraulic system of double bidirectional variable hydraulic pump and the bidirectional quantitative motor, the drive system for crawler type machinery, advantages, in the walking system design process can reasonable calculation and power matching, reasonable selection of power components, the universal value of engineering application.

Abstract: Vehicle ride comfort determines vehicle performance, affects the ride comfort and reliability. Aimed at the problems in establishing the vehicle dynamics model by traditional classical mechanical methods, the vehicle ride comfort simulation analysis scheme on the basis of virtual prototyping technology is put forward. Based on Multi-body dynamics, the virtual prototype vehicle model was established. According to the national standards, the vehicle ride comfort simulation scheme was designed, including the simulation test with sine wave excitation, the simulation test on triangular bump road and random uneven road. Through the test, the root mean square of weighed acceleration can be got and the evaluating process can be accomplished according to the ISO standard. The results show a good ride comfort of the testing vehicle. Virtual test provides a useful reference for the complex mechanical product design of physical prototype.