Applied Mechanics and Materials Vols. 477-478

Abstract: In order to impede stress wave propagation in mechanical boom system, this paper study on contact interface rough effect on stress wave propagation. The model of stress wave propagation was established. On stress wave test platform, it was tested that stress wave through the contact interface roughness between two contact interface. The results show that small surface rough is benefit for stress wave through contact interface; with the surface rough increase, stress wave through contact interface reduce.

Abstract: In order to make the school bus seat structure meet the seat safety standards, in this paper the finite element simulation analysis method was adopted to establish the finite element model of the school bus seat frame. Based on this model, respectively, at two different height of seat, and two different numerical test forces were applied to the school bus seat, and in two cases the performances of the seat frame were analyzed and its safety was evaluated. For the analysis result improvement design and modal analysis were conducted, and all those ensure the seat performance to meet standards of school bus seat safety and requirements of seat comfort.

Abstract: The mechanical state recognition process, the feature parameter vector problem of high dimensionality, this paper designed a system to achieve the mechanical condition of the driving conditions online monitoring and evaluation. The system has accumulated a large number of driving condition monitoring data for data mining provides a data source, but also to ensure all of this paper's findings authentic.

Abstract: With the mature of floating offshore wind turbine technology, floating wind farm building in the deep sea becomes an inevitable trend. In the design of floating offshore wind turbine, the change of structural form is the main factor influencing hydrodynamic performance. This research, taking a typical sea condition in China's coastal areas as the object of study, designs a novel semi-submersible foundation for NREL 5 MW offshore wind turbine in 200 m deep water. In the design, deep-draft buoys structures are used to reduce the force of waves on the floating offshore, while damping structures are used to optimize the stability of wind turbine and reduce the heave amplitude. By means of numerical simulation method, the hydrodynamic performance of semi-submersible support is studied. Meanwhile, the response amplitude operators (RAOs) and the wave response motions of platform are calculated. The results in time domain indicate that the floating wind turbine system can keep safe and survive in the harsh sea condition, coupling wind, waves and currents. It is showed that the designed semi-submersible support of platform has excellent hydrodynamic performance. This change of structural form may serve as a reference on the development of offshore wind floating platform.

Abstract: With the wind turbine become larger due to technology development, the effects of wind load on the dynamic behaviors of wind turbine system play a more important pole, especially for offshore wind turbine system with floating platform. To research such effects, the dynamic behaviors of a new semi-submersible platform of a 10 MW wind turbine in 300 m deep seawater are studied in this study. Firstly, frequency domain analysis is done to show the performances of the semi-submersible platform and prepare hydrodynamic coefficients for time domain analysis. Then time domain analysis is studied with the consideration of the coupled load effects of the wind turbine floating platform, mooring lines and ocean environment. Main load components on the wind turbine floating platform are disposed, and the effects of wind load are studied as a key point. Though the result shows that wave load still dominates the contribution to motions of rolling, heaving and surging, the contribution of wind load becomes more important than current load in the operation case, which is different of traditional floating platform.

Abstract: Deep-sea offshore wind resources are extremely abundant. Large offshore wind turbine is the future trend to utilize of deep-sea offshore wind resources. Because of excellent heaving, pitching and rolling performances, tension-leg platform ( TLP ) is one of best floating support structures for large wind turbine. However, under extreme environment condition, the large tendons which are required for large offshore wind turbine TLP platform will meet extreme response, even lead to damage. Extreme response of tendon of a 10 MW offshore wind turbine TLP platform ( an improved MOSES TLP ) in the extreme environment condition is studied here. It is showed that the global motions can meet the basic requirements for 10 MW floating wind turbine, where the maximum angle of TLP is less than 10⁰. Meanwhile, the maximum tendon tension of the TLP in the simulation is less than the breaking force, which meets the requirements of API rules on tendon of TLP.

Abstract: A delay-coupled flexible-joint system is investigated in this paper. Because of the different time scales, the flexible-joint system could be transformed into a fast subsystem and a slow subsystem. The geometric singular perturbation method is used to obtain the slow manifold defining as the equilibrium of the fast subsystem. The eigenvalue analysis of the fast subsystem reveals a relation between the stability of the slow manifold and the time delay. The analysis results provide an idea of suppressing the small amplitude periodic oscillation via adjusting the time delay. Numerical simulations are performed to display the effectiveness of this method.

Abstract: For the passive and semi-active suspensions are characterized as with constant parameters which cannot cope with time-variant road conditions, the suspension results are difficult to be satisfied. Although, the active ones are better than previous two on suspension performance, until now which are still far from real application for the drawbacks of complicated structure, large volume, costly, and difficult maintenance. Here, Ball Screw (BS) is with the characteristics of smaller volume, precise positioning, and well handling high-speed forward and backward transmissions. Instead of hydraulic or pneumatic mechanisms used for vehicle suspension, BS is adopted to be the main body of the proposed New Adaptive Suspension System (NASS). Besides, in order to overcome the unavoidable time-delay resulted from mechanical or computational operations, the Kalman filter, integrated with suspension controller, is used to estimate the road conditions. The effectiveness and feasibility of this proposal are confirmed through simulation studies.

Abstract: This paper has conducted a structural analysis by workbench after establishing a stable platform for automotive three-dimensional model, primarily concerning whether the platform can provide a benchmark to meet the requirements of equipment, including the numerical analysis of whether the platform tilt angle under load can achieve the requirements as well as the scheme of improvement direction of the structure.

Abstract: Based on Roller Straightening Theory and Elastic-Plastic Beam Research, A Appropriate Mathematical Model of Straightening has Set up.The Author Regards the Tube as a Continuous Bending Beam and Discuss in Detail the Relationship between the Straightening Force and the Bending Moment. Calculating the Amount of Deflection for Tube. in this way ,it Provided a Scientific Basis for the Copper-Clad Steel Tube Straightening Parameter Set and Engineering Application.