Applied Mechanics and Materials Vols. 204-208

Abstract: The ship impact is one of the main reasons, causing damage to pile wharf. In order to explore the pile bent property under the horizontal load, the finite element numerical analysis software was used to construct the model of the bent, and the data of each pile of the bent has been obtained. According to this data, the basic changing rule of the bending moment and displacement of piles along the pile length was found. Comparing a single vertical pile and fork piles, the difference between them was got. And on that basis, this article preliminarily researched the elastic-plastic characteristics of pile bent.

Abstract: Experiments were conducted on 7 simply-supported composite steel-concrete beams (SCB) with compact steel sections to investigate their interface mechanic behavior. The influences of different loading mode, degree of shear connection and stud arrangement are discussed. The test process, specimen failure matter and uplift distribution along the span of the beam are analyzed. Based on the experimental research, the formulae are derived for the interface slip and uplift rigidity of the stud in composite steel-concrete beams. The present values bench-mark finite element analysis of load bearing capacity and deflection of composite steel-concrete beams.

Abstract: In this paper, the generalized differential transform method is implemented for solving time-fractional wave equations in fluid mechanics. This method is based on the two-dimensional differential transform method (DTM) and generalized Taylor’s formula. The results reveal the method is feasible and convenient for handling approximate solutions of time-fractional partial differential equations.

Abstract: The current researches on bolt length are rarely concerned with self-bearing characteristics of anchorage surrounding rock，its stress response is seldom used to analyze the bolt effective length. Tangential stress σθ of surrounding rock is sensitive to mechanical variation of surrounding rock plastic failure fields. When surrounding rock bolted, the distribution curve of σθ presents internal and external peak values from the surface rock to the deep rock, which is verified by numerical simulation. Internal peak value of σθ curve increases with the bolt length, which means the bearing capacity of surrounding rock in plastic failure division is improved, correspondingly, external peak value decreases which shows the supporting behavior of the deep rock is weakened. The results of numerical simulations prove that there exists an effective value of bolt length. If bolt length beyond it, the bearing capacity of anchorage surrounding rock cannot be improved obviously.

Abstract: Based on Numerical Manifold Method (NMM), a novel method is presented for computing Stress Intensity Factor (SIF) of cracks. The Williams expansions are employed as the analytical solutions in the mesh containing the crack tip. And high-order polynomial functions are used as the numerical solutions in the surrounding meshes. Then the SIFs are computed via combination of the numerical solutions and the analytical solutions. Meanwhile, the meshes in NMM need not conform to the physical boundaries including the crack edges, allowing the cracks arbitrarily align within the meshes. The given example shows the validity of the method.

Abstract: The Influence of six kinds of combinations of different boundary conditions on the maintenance of homogeneity of atmospheric boundary layer in computational wind engineering was investigated. The inlet condition was applied by either prescribing velocity and turbulent quantities or using a periodic boundary. The top boundary condition includes symmetry, prescribing velocity and turbulent quantities, constant static pressure and applying driving shear stress. Numerical results show that the stream-wise velocity and the turbulent dissipation rate are almost immune to boundary conditions, but the turbulent kinetic energy is affected by boundary conditions dramatically. Best maintenance can be obtained by using periodic boundary condition at inlet and outlet and applying driving shear stress on the top of the domain.

Abstract: From the basic equation of dynamics, the precise expression of the relationship, which is between the horizontal natural frequency and pressure load of the beam at two ends elastic fixed and subjecting to vertical pressures, is obtained. Its approximate expression derives from the variational method. By comparing the precise numerical solution and the approximate solution of the beam at two ends elastic fixed and subjecting to vertical pressures, the conclusion of approximate linear relationship that is between the square of the natural frequency and axial force of the beam at two ends elastic fixed and subjecting to vertical pressures is got. And the difference between the approximate solution and the accurate numerical solution is small, which can meet the requirements of accuracy on engineering. On this basis, as long as the natural frequencies of the structure at two load conditions are measured by experimental methods, elastic buckling load of the compressed beam can be identified. So the no damage test method to identify the elastic buckling load of the structures is given.

Abstract: The distinctive paper is devoted to correct discrete-continual finite element method (DCFEM) of structural analysis based on precise analytical solutions of resulting multipoint boundary problems for systems of ordinary differential equations with piecewise-constant coefficients. Corresponding semianalytical (discrete-continual) formulations are contemporary mathematical models which currently becoming available for computer realization. Major peculiarities of DCFEM include uni-versality, computer-oriented algorithm involving theory of distributions, computational stability, optimal conditionality of resulting systems and partial Jordan decompositions of matrices of coeffi-cients, eliminating necessity of calculation of root vectors.

Abstract: A model of hematopoiesis with time delay and impulses is studied. Based on the Lyapunov function method, uniform stability and uniform asymptotic stability of the equilibria is discussed.

Abstract: In the present paper, the asymptotic solution of modal damping ratio of stay cable-passive damper system with the influence of cable bending stiffness and damper stiffness was derived. Maximum modal damping ratio and corresponding optimal damping coefficient, which indicated the relationships of the characteristics of the damper and the cable bending stiffness was theoretically analyzed to obtain their close solutions. On the basis of these close solutions, numerical analysis of modal damping of stay cable-passive damper system with the effects of cable bending stiffness and damper stiffness was conducted. The numerical and analytical results show that the maximum modal damping ratio decrease and the corresponding damping coefficient increase, when considering the influence of the damper stiffness and the cable bending stiffness.