Applied Mechanics and Materials Vols. 204-208

Abstract: Semi-submersible plays an important role in ocean oil and gas exploitation. This paper carried out some researches for the dynamic positioning system (DPS) of a deep water semi- submersible. Mathematic modal was made, and a special program was created with M-language for the time-domain dynamic analysis of the dynamic positioning system of the deep water semi-submersible, on basis of the mathematic modal. PID control strategy, kalman filtering theory and optimal thrust allocation method were used in the analysis. Simulation result indicated the DPS of this platform is safe and efficient.

Abstract: The author firstly summarized the principles, performance and theoretical resilience model of the new type electromagnetic damper. The theoretical resilience model is further improved on this basis—normalizing the impact of vibrant frequency and vibrant amplitude on resilience as the impact of single parameter velocity amplitude. The results show that improved model can give a better effect as shown in experiment. This lays a sound foundation for simulation calculation in developing products using for practical engineering and installing the structural vibration reduction system of electromagnetic damper.

Abstract: A perturbation procedure, in which the elliptic perturbation method and the hyperbolic perturbation method are applied, is presented for predicting heteroclinic connection of limit cycle or self-excited ocsillator. The limit cycle can be analytically　constructed first by the elliptic perturbation method after Hopf bifurcation, in which the amplitude of limit cycle can be　controlled by the modulus of elliptic functions. The heteroclinic trajectories, which are formed by the heteroclinic connection of limit cycle, can also be constructed by similar perturbation　procedure but adopting the hyperbolic functions instead of　elliptic functions. And the criterion of heteroclinic connection is given in the perturbation procedure. A typical self-excited oscillator is studied in detail to assess the present method.

Abstract: EPS module is connected like roy brick to form a hollow wall, then grouting the without vibrate concrete to form the thermal-insulating shear wall. Based on the experiment data, analyzed the aseismatic behavior of EPS module shear wall under horizontal cyclic loads by ANSYS software. Compared EPS module shear wall with the traditional shear wall on crack status, stress and strain distribution, rigidity, and attenuation coefficients of rigidity. Compared the experiment data with the finite element analysis result by ANSYS, discussed the method of analyzing this new plate material by finite element analysis, which can be basis for experiment and analysis on this material.

Abstract: In this paper, based on the deformation of bonded tensile-compression prestressed concrete beam, the nonlinear analyses are presented about whole loading process of tensile-compression prestressed concrete beam by internal force equilibrium and deformation compatibility of cross section. Then the M-f computation programs are developed, and the computational results are consistent with that of test. Finally, the ANSYS programs are used to analyze and test the computational results from M-f computation programs. Research findings in this paper provide a basis for further study of tensile-compression prestressed concrete.

Abstract: It is a hot research project of single slide skill on the U-ground in Winter Olympic Games. According to the force acting on the U side by snowboarder, considering Newton's second and third laws, the maximum twist formula are derived, the calculating results show that twist angle is increased up to 15% by using our model.

Abstract: This paper studies the nontrivial positive solutions to a semilinear elliptic system in the n dimensional Euclide space. By constructing new variational space, using the linking theorems and some embedding theorems, this paper proves the existence of positive solution to a semilinear elliptic system, and improves the results of Li and Wang.

Abstract: This paper studies the reductions and properties of strictly contact diffeomorphisms in contact dynamical system. By constructing new norms and using some estimate techniques, this paper proves that the induced homeomorphism of contact homeomorphism is Hamiltonian, and computes the norm of such homeomorphism under reduction in contact dynamical system.

Abstract: The original signals always mix with certain noise through blasting engineering test of underground structure, such as fan noise, environmental noise and mechanical noise. That makes the useful information of signal characteristics hidden in the noise signal to cause major error for the site test. The superposed signals of the original signal got by using numerical simulation and artificial white noise signal were processed through different de-noising methods based on wavelet transform. After the de-noising effects were evaluated by the evaluation standard signal de-noising performance, the best wavelet function, the effective scale of wavelet decomposition, and the threshold estimation rules were got settled on. Finally, the best de-noising method of blasting vibration signal is got to lay the foundation for the underground structure safety evaluation based on the wavelet transform theory.

Abstract: The dynamic behavior is an important index to evaluate the seismic property and structure damage of historic pagoda. On the base of the research of protection technology on Jinaozhou pagoda, the key points and schemes for applied ambient random excitation technology to determine the dynamic behavior of ancient masonry pagodas is introduced. Test results obtained are ideal, and obtain some datas that are beneficial to Jinaozhou pagoda preservation through comparison of test results during four years. It is believed that the present research can provide a valuable reference for the eternal protection, reasonable development and utility & Long-term health monitoring of similar ancient pagodas.