Applied Mechanics and Materials Vols. 444-445

Abstract: The couple shear wall structures are well known for their anti-lateral stability, they have a promising future in macro complex high-level structures. Coupling beam dampers are the key components of coupled shear wall structures. In this manuscript, metallic in plane yield coupling beam damper with four types of poration and different pore areas are analyzed by Finite Element Method. It is found that the hourglass-shaped poring coupling beam damper has superior hysteretic behavior and higher carrying capacity comparing to other types of poring damper. In addition, the optimized poration parameters are further obtained by using Kriging surrogate model, which maximize the carrying capacity and enhance hysteretic behavior of the hourglass-shaped coupling beam damper.

Abstract: This paper presents the calculation method for fatigue load parameters of light-rail traffic of the steel-concrete joints of Caiyuanba Yangtze River Bridge. Based on that the light-rail vehicles meet conforms to the normal distribution assumption, rain-flow counting method is adopted for the internal force amplitude of the steel-concrete joint induced by the light-rail traffic, which is then equivalent to fatigue load of constant amplitude according to linear cumulative damage criterion from Miner. With regard to design and research for similar bridges, this method can be referred to.

Abstract: The finite element modal analysis was used to study natural frequency of circular saw blade, when slotted. Finding the frequency of slotted is smaller than no slotted saw blade, showing that slot can have the effect of noise attenuation. The increasing of slot length, slot width, slot position, slot number can reduce the natural frequency of circular saw blade on the whole. The orthogonal text was used to study slot parameters. Finding that slot parameters’ influence of primary and secondary relations on saw blade first five natural frequency is slot position > slot number> slot length > slot width.

Abstract: The spline finite point method (SFPM) that is based on the third order shear deformation beam theory (TSDT) is introduced to investigate the shape control of smart beam, which is integrated with PZT and SMA actuators. The governing equations of the smart beam are given by the SFPM and TSDT. The shape control problem is formulated as the problem of minimizing the objective function to study the shape control effects of the smart beam under the different control methods. To demonstrate the less computational cost and higher accuracy of the SFPM, several numerical examples are calculated. The advantages of both smart materials and the effective control of smart structure can be obtained by the hybrid actuators.

Abstract: To calculate the characteristics of the lateral vibration in the main shaft system of the hydro-turbine generating set, a three-node elastic shaft element was proposed. Its dynamic equation was derived and the interpolation function, translational inertia matrix, rotational inertia matrix, gyroscopic matrix and the stiffness matrix were obtained. Based on Matlab platform, a FEM program was developed for calculation and its correctness was verified through a numerical example. The study shows that, compared with the method using two-node shaft element, the results of the three-node shaft element are closer to the theoretical solution and the accuracy is higher.

Abstract: In the paper, the stability of the double-walled carbon nanotubes (DWCNTs) under the initial axial stress are studied. Galerkin and harmonic balance method are used to analyze the relation between the amplitudes and the frequencies of the tubes. The results show that the critical initial stress plays a significant control role in the amplitude-frequency curves. When the initial axial stress is less than the critical initial stress, DWCNTs have twice dynamical mode transitions corresponding to twice noncoaxial vibrations, however, when the initial axial stress is larger than the critical initial stress, the topological forms of the amplitude-frequency curve are changeable, which are corresponding to coaxial vibration or three possible noncoaxial vibration type.

Abstract: Considering two-way fluid-structure interaction and using finite element software ANSYS simulation study of cylindrical pier at different flow rates caused by the interaction of the river and pier piers vibration problems, through the discrete solution of wet modal method, and combined with engineering example, the analysis results using Lanczos method extraction, introduction of green's function of point source, using the finite element-boundary element analysis wet modal and wet frequency of the structure. Numerical results show that: Frequencies of wet modal than no fluid medium under the influence of modal frequencies is much lower. So for underwater structures, when analysis the modal,it is must be considered the fluid influence of wet modal.

Abstract: In this paper the NHDMOC method which succeeded in studying stress wave propagation with one dimensional strain was applied to study the one-dimensional stress wave propagation. In this paper, the ZWT nonlinear visco-elastic constitutive relationship with 7 parameters to NHDMOC, and corresponding equations were deduced The equations was verified from the comparison of elastic stress wave propagation in SHPB with elastic bar and visco-elastic bar respectively. Finally the dispersion and attenuation of stress wave in SHPB with visco-elastic bar was studied.

Abstract: The piecewise quadratic Hermite polynomials are employed in the finite element context to analyze the static and free vibration behaviors of Euler-Bernoulli beam. The desirable C1 continuity is achieved for the piecewise quadratic Hermite element that is required for the numerical solution of the Galerkin weak form of Euler-Bernoulli beam. In contrast to the classical cubic Hermite element, the piecewise quadratic Hermite element has a piecewise constant curvature representation within each element and thus the integration of the stiffness matrix is trivial. Several benchmark problems are shown to demonstrate the convergence properties of the piecewise quadratic Hermite element. The frequency error of the beam free vibration with this quadratic Hermite element is derived as well. Numerical examples consistently verify the analytical convergence rates.

Abstract: Basic principle of generalized gradient based digital image (DIC) method for subpixel-accuracy displacement measurement is discussed. The proposed method can cope well with lighting illumination variation or grayscale intensity change on the object surface during measurement by adopting a linear intensity change model, which overcomes the limitations in existing linear least squares based spatial gradient method by adopting constant model. To evaluate the proposed methods, both computer simulation and actual experiment have been carried out. The results show that the proposed method can measure displacement accurately even when substantial intensity variations exist in the experimental images.