Applied Mechanics and Materials Vol. 900

Abstract: The flexible flywheel assembly used in the powertrain of an automatic-shifting automobile connects the engine crankshaft and the torque converter and provides a protection to potentially damaging axial movement between the crankshaft and the torque converter. In this research, a fully parameterized model of a flexible flywheel assembly is created, and then optimum design procedures with a zero-order optimization scheme are applied to investigate two cases: the first is to maximize a summation of modal frequencies of the structure; the second is to minimize the maximum equivalent stress in the model. Both optimum design cases have shown improvement in their objective functions, with one of the modes in the first case achieving the greatest improvement of +45.7%.

Abstract: The uncertainty of mechanical system performance is strongly influenced by the properties of system components such as mass, stiffness-damping coefficient, and friction coefficient. Based on computational simulations, the system performance under uncertainty conditions can be estimated. However, the nonlinear dynamic behavior of friction is difficult to simulate in numerical simulations, this research is therefore employed a smooth stick-slip friction force model instead of the Coulomb friction force model. Monte Carlo simulation (MCS) combined with multibody dynamic (MBD) simulation is proposed to evaluate the uncertainty characteristics of the system components and stick-slip friction force between two contacting bodies. Numerical simulations applied the proposed method were performed to consider the effects of uncertainty of friction coefficient on the machining accuracy of a three axes CNC (Computer Numerical Control) machine tool.

Abstract: This research presents a dynamic analysis of a large-scale hydraulic cylinder actuator via numerical simulation. A model of the actuator built with dynamically parameters is implemented basing on fluid mechanics and vibration theories. In which, coefficients of viscous damping and stiffness generated by compressibility and viscous characteristics of hydraulic oil are considered. Hence, the large-scale hydraulic cylinder actuator can be investigated via an equivalent model of mass-spring-damper. In order of obtaining the system response, numerical simulation is done with some realistic actuator parameter sets. The results are consistent with reality and can be used as valuable fundamental for large-scale hydraulic cylinder actuator design.

Abstract: In this paper, two kinds of spatial position and attitude controllers based on fractional order algorithm and algorithm are designed. Based on the basic assumptions, the model is established and the control of the spatial positioning of the manipulator is studied. The control effects of traditional controller and fractional order controller are analyzed and compared by numerical simulation method. At the same time, the effects of parameters and of fractional order controller and controller on system performance are simulated and analyzed. The results show that the fractional order controller has faster and better robustness than the traditional controller. The research of fractional order controller has become a new method to predict the space trajectory tracking and positioning of the manipulator and to ensure the positioning accuracy of the manipulator.

Abstract: The mold clamping mechanism is an important mechanism of injection machine, and the mold clamping mechanism with good kinematic characteristics is the goal pursued when designing injection machine. Traditionally, the mold clamping mechanism must have at least one toggle effect at clamped position; when the mold is at open position, the mold clamping mechanism does not need to have toggle effect. In this paper, 2 mechanisms of existing patents are used to illustrate the process of the dimensional synthesis and kinematic analysis of mold clamping mechanism with double toggle effects at clamped position. The kinematic characteristics of 2^nd mechanism is better than 1^st mechanism.

Abstract: The simulation and application of industrial robots has developed very quickly in recent decades. Along with the development of computer science, a lot of softwares to perform dynamic simulation have been created. The results of simulation can be used for layout evaluation, kinematic, dynamic study, off-line programming to avoid obstacle and for design mechanical structure of robots. A co-simulation of 2R industrial robots have been performed by Recurdyn and Matlab. The input parameters are executed under Matlab, and then exported to Recurdyn environment. Kinematic parameters will be executed by RecurDyn then exported to Matlab. The main tasks of this paper are performing 2R robotic manipulator kinematic simulation in two postures with the same trajectory and the same time. Thus, the result of simulation can be compared with theories. Finally, a real 2R robot model was used to verify the trajectory with CAE simulation.