Abstract: In this paper, based on the nonlinear elastic theory, dynamic modeling for a thin plate with large deformation is proposed considering high-order deformation terms using hybrid-coordinate formulation. Through the calculation the potential energy and kinetic energy of the plate, rigid-flexible coupling dynamic equations is established. It is shown that the difference between the deformation results obtained by the present high-order dynamic model and those obtained by one-order approximate dynamic model is not significant in case of large deformation ,both them can calculation large deformation problem. However, the amplitude of vibration obtained by the present high-order dynamicmodel is smaller than that obtained by one-order approximate dynamic model. Furthermore, dynamic stiffening and softening effect of the rigid-flexible coupling system undergoing translational large overall motion is investigated. It is shown that with the reduce of the modulus of elasticity, the influence of the translational acceleration on the vibration frequency of the rigid-flexible coupling system is more significant.
Abstract: MDO and reliability design are independently processed in the traditional aircraft design. The designs process is thus consuming compute intensive, so that integrated design of MDO and reliability is required. To achieve the integration, there are two problems needed to be solved. First, a reliability function needs to be expressed by performance design parameters in a probability form. Second, the reliability function needs to be imported into MDO arithmetic. For the first one, stress-strength interference theory is useful. According to the theory, performance design parameters are described in the formulas which calculate probability of reliability. For the second, the reliability function is considered as a part of optimization objective functions or as a constraint function. The simulation of aircraft design shows that the above method is useful and effective to the actual project.
Abstract: High cycle fatigue of blades caused by forced vibration is an outstanding problem in turbine machines such as turbo engines and ground gas turbines. Dynamical sensitivity analysis (DSA) is put forward and the mathematic model is erected according to blades. DSA on blades includes sensitivity analysis on inherent characteristic (DSAI) and sensitivity analysis on excitation environment (DSAE). The influence laws of dynamical parameters are gained through DSA, and therefore the optimization design on blades is feasible. DSAE is presented by dint of numerical methods, aerodynamic forces in engines possess multifrequency and spatial distributing characteristics, so DSAE on blades is performed against these characteristics and some results are obtained. Finally the resonance criteria are advanced and a new dynamical design method is put forward.
Abstract: In order to obtain a second-order mathematical model of the ball screw feed drive systems in the designing stage, this paper proposed a simulation modeling method based on model reference adaptive system. In this method, a parallel model reference adaptive system, which regarded the mechanical model as the reference model and regarded a second-order model as the adjustable model, was designed use only input and output measurements based on Popov’s hyperstability theory. And the second-order model’s parameters could be achieved by simulation. The proposed method was confirmed effective through case study. The results show that: the second-order system’s parameters can be identified correctly, and the output of the mathematical model can be followed preferably by the second-order system. The error is less than 0.02mm.
Abstract: In this article, quasi-static tensile and dynamic tensile tests of three common bolt materials (three kinds of steels) were conducted, and their stress-strain curves at various strain rates were obtained. By this means, the mechanical properties of three common bolt materials were analyzed. Based on the John-Cook model, author established the constitutive relation models of three materials which could describe their strain rate dependence, and used these models in the numerical simulation. The research show us that bolt material strain rate effect not only could affect the bolt impact strength, but also could not be ignored in the study of impact strength of equipments connected by bolts. The research has great significance to the study of impact resistance strength of equipments and bolts.
Abstract: HTC 100 CNC lathe is a heavy machine tool. The lathe bed is the important part of the machine tool. The static characteristic of the lathe bed directly influence the machining accuracy and production efficiency of the machine tool. At present, the lathe bed design general depends on the designer’s experience. In this paper, the static analysis of the HTC100 CNC lathe bed is carried out with ANSYS 12.0. The node equivalent stress distribution cloud, the total deformation distribution of Lathe bed and the maximum distortion under various kinds of working conditions are obtained. According to the result, the structure of lathe bed design tends to conservative and the distribution of static stiffness is unreasonable, which is necessary to optimum design.
Abstract: This paper presents a flexible deviation model of sliding-doors developed using influence coefficient method. By introducing the deviation factors such as seal strip reaction force and door’s dynamic deformation, the closed-loop relationship of size of the sliding-door system when it is in closed state is further established. Then based on the influencing relationship of the sliding-door deviation on the system flexibility and stiffness, the influence of the deviation on the door dynamic performance is obtained. Finally, through analyzing the frequency response of a real sliding-door, the optimal door deviation design is proposed and the effectiveness of the method is also verified.
Abstract: Gear box in caterpillar is designed with the static strength theory. While the dynamic characteristics of planetary parts in different working condition is difficult to obtain with the limit of traditional method, so research on reliability and fatigue life prediction of gear box is very difficulty which result that designed life is much longer than practical life. The reliability of caterpillar is affected deeply. The dynamic loads suffered by gear box in different working condition is obtained based on running simulation with MSC.ATV, and then the fatigue life of planetary frame is calculated with fatigue life prediction system of gear box. The study case prove the new method is feasible.
Abstract: With the applied development of Cam mechanism in modern civilization, the running speed of cam mechanisms is increasingly high , the inertial force of system follower raced up.Dynamic analysis and dynamic design must be considered when analyzing high-speed cam mechanism. This article takes combustion engine high-speed Valve cam for example, adopt cyclical motion rule when calculating , follower system would be equaled to Single freedom dynamic model and movement equation would be established. Meanwhile, establishing the movement equation . Use MATLAB to work dynamic response change curve to obtains the different period ratio to push the regulation sector principal oscillation response and ttop the secto sor hangover response far the influence, thus makes the explanation to the period ratio reasonable choice.
Abstract: 6_PUS parallel mechanism is a new type manipulator which has two guide rails, along which six sliders connected with tie rods by hooke joints are driven by linear motor and then motion platform is driven by tie rods. In order to obtain precision loci of motion platform, linear motor should be controlled exactly. During the modeling of 6_PUS parallel mechanism, RBF NN is selected to approach the nonlinear of this manipulator, and neuron PID controller is used to regulate the controlled object. In this paper, regulating rules of the control system is introduced in detail, and the control efficiency is proved by experiments which show neuron adaptive PID controller can deal the nonlinear of 6_PUS parallel mechanism and get preferable control precision to ordinary PID controller.