Abstract: The study of WJ-8 rail fastening is about the relationship between lateral horizontal force and rail’s lateral displacement, and the rail fastening’s transverse stiffness was obtained since the rail slipped. The rail lateral displacement was measured by using the loading device of rail’s lateral horizontal force which was changed as needed. Moreover, when the lateral horizontal force changes, it was analyzed that how it affected rail’s lateral displacement and rail fastening’s transverse stiffness under different bolt torque conditions. Therefore, the recommended value of transverse stiffness is acquired which is based on analyzing the test results.
Abstract: The structure and principle of the two-stage pressure hydro-pneumatic spring were introduced. the physical and dynamic vehicle models with it were established under AMESim environment. Static characteristic curves of the two-stage pressure hydro-pneumatic spring were drawn. A single chamber hydro-pneumatic spring was used to compare the suspension dynamic travel and body vertical acceleration of the vehicles equipped with two-stage pressure hydro-pneumatic spring. The results show that two-stage pressure hydro-pneumatic spring can effectively enhance the vehicle riding comfort by decreasing body vibration.
Abstract: Power transmission towers are major equipment of State Grid,the safety of the tower foundation is very important to the power system,nondestructive testing to foundations is necessary when excavation is impossible.In this paper, the dynamic response analysis of the impact-echo method for power transmission tower foundation with flaws is solved based on finite element method; the result of numerical analysis is consistent with the depth of the setting flaw, which shows the feasibility of detecting flaws in transmission tower foundations with the impact-echo method.
Abstract: Laterally interconnected air suspension combines the right and left air springs with pneumatic pipes, which can protect the auto-body parts from fatigue damage and increase the service life of vehicles. The mathematical model of full vehicle with laterally interconnected air suspension was established based on the analysis of its working principle, and a test bench was built. The simulation and experimental results show that, laterally interconnected air suspension can reduce the peak of dynamic body torsion load effectively, especially for steady state conditions, in which the body torsion load caused by the spring force can be nearly eliminated.
Abstract: Aiming at the uncertainty propagation analysis in modeling of FE model for structure, supported Vector Regression (SVR) method was presented to construct the implicit mapping between structure response and uncertainty parameters. The computational process of forward transfer of uncertainty parameters has been clarified. Three level testing criteria was used to evaluate extensively precision and generalization ability of RSM(Response Surface Modeling) based SVR. The super parameters in RSM were clarified through graded cross-validation. Uncertainty quantization analysis of GARTEUR model prove that the RSM based SVR has higher accuracy. Confidence level 95% finite element model was built because the confidence interval of nature frequency mean-value and variance were computed.
Abstract: A dimensionless nonlinear state-space model was established considering the structural particularities of digital hydraulic cylinder, and dynamic bifurcation characteristics of the system were analyzed and validated based on MATCONT. The results show that, when the piston diameter, valve orifice area gradient, ball-screw pitch and the maximum desired speed are not designed appropriately, digital hydraulic cylinder is prone to Hopf bifurcation. Limit cycles that the stable and the unstable neutralize each other at subcritical Hopf bifurcation points, causing the system tracking outputs divergence from continuous oscillation to increasing oscillation. Losing synchronism of stepper motor is essentially a form of the instability caused by system supercritical Hopf bifurcation.
Abstract: This paper aims to get the kinematic performance and control parameters of moving mooring marine current turbine system such as velocity, period of motion, speed increasing ratio, motion trail, tension of cable, steerage and timing of control, strength of the platform and etc. This article first gets the hydrodynamic parameters with CFD and then builds the equations of motion, and the system simulation test was carried out with Matlab and Adams. The result shows that this moving mooring marine current turbine system can move on a designed trajectory by steering in flow environment. The velocity of the platform is about six to eight times to the current speed. The simulation lays a foundation for the development of engineering prototype. There have been plenty of information proved the theoretical breakthrough but we still need to face great challenge in the project practice in the coming future.
Abstract: Natural Gas Hydrate has become a research focus at home and abroad at present. This paper expounds the concept of natural gas hydrate and its types. Analyze its study process and research situation, and make a brief description of its distribution, mining and related environmental problems by tracking the discovery history of gas hydrates. Then put forward the problems in instant need of solving and the key research contents.
Abstract: Stainless steel is difficult to machine, especially micro-hole machining. In order to obtain the effect of drilling force by tool material and cutting parameters, the drilling experiments on stainless steel 1Cr18Ni9Ti have been done by diameter of 1.2 mm containing cobalt high speed steel and carbide drill. According to the experimental results, analysising the reason of drilling force change under different parameters and establishing a carbide drill drilling force empirical formula which combined with the regression analysis method.