Applied Mechanics and Materials Vols. 94-96

Abstract: The purpose of the paper is to present analytical solution of curved beam with clamped-pinned ends under thermo load based on the principle of thermal expansion and theory of virtual work. A class of equations for in-plane displacements at three freedom direction and internal forces in the cross-section of statically indeterminate curved beams under thermo load are derived explicitly. In the case of infinite limit of radius, these equations coincide with that of the straight beams. Compared with the results of FEM, the analytical solutions by the proposed formulae are accurate. The analytical solutions obtained in this paper would provide a scientific base for further study and design of the curved bridges.

Abstract: Horizontally curved box girder bridges inherently exhibit complex torsional and distortional behavior as well as bending due to the initial curvature. As to the horizontal curved composite box-girder bridges with corrugated webs, diaphragms were arranged reasonably to reduce torsional and distortion effect for safety and stability due to the coupling of bending and torsion effect for initial curvature and reduced bending stiffness in horizontal direction for corrugated steel webs. Finite element models for a 3-spans continuous horizontal curved composite box girder bridges with corrugated webs were established. Comparing the ratio of warping normal stress to bending normal stress, the influence of the number and spacing for diaphragms on distortion control for curved bridges is investigated. Extensive parametric studies (including central angle, the aspect ratio of the box section, the spacing of the intermediate diaphragms)are performed and the design suggestions for the maximum spacing of the intermediate diaphragms are presented.

Abstract: Based on the general description of the coupling deformation of composite sandwich thin-walled bar and the structural characteristics of rectangular sandwich bar, this paper studies the decoupling methods and approaches for composite sandwich thin-walled bar control equations and puts forward the decoupled control equations and boundary conditions.

Abstract: The H-beam with corrugated webs is a new type of H-beam, whose webs are produced by substituting corrugated webs for flat webs. In this paper, analysis was conducted to study main design principles for H-beam with corrugated webs used in a project, including component design and joints design. Compared with H-beams, the products have superior load-carrying capacity and more favorable economic advantages.

Abstract: This paper deals with non-linear free vibration of double-deck reticulated shallow spherical shell by applying the non-linear theory of double-deck reticulated shallow spherical shell established by the author. Model function is supposed to be theory solution of small deflection. The proper equation of double-deck reticulated shallow spherical about time functions with two types of boundary conditions is derived by using Galerkin’s method. At the same time, the analytical expression of ratio of non-linear vibration and linear vibration is deduced and the non-linear effect about amplitude is discussed. Numerical examples are given as well.

Abstract: Unconfined compressive strength of various mixing proportions and ages of nanometer silicon and cement-stabilized soils（NCSS） are tested ,and the rules of compressive strength are got. Hydration products and microstructures of NCSS are discussed by means of XRD and SEM technology, and microstructural mechanisms of NCSS are analyzed. Results show that nanometer silicon powder added to cement-stabilized soil(CSS) can sharply improve the compressive strength of CSS. More Calcium silicate hydrates(C-S-H) and other hydration products can be produced in the process of secondary reaction of cement and water added nanometer silicon powder. X ray diffraction tests indicate the kinds and quantities of C-S-H increase with nanometer silicon contents. Strengths of NCSS are bettered by increasing jointed strength changed from edge-edge, edge-face connectios to cementation connections affected by increasing hydration products. Large pores of NCSS can be greatly decreased by adding nanometer silicon powder, and hydration products filling in the pores make NCSS more dense materials.

Abstract: Nonlinear finite element analysis of the cast steel spherical joint is performed by using ANSYS program. The deformation process, the failure mode and the effects of parameters on bearing capacity for the joint are analyzed. The results show that the outer diameter of sphere D, wall thickness of sphere t, external diameter of cast steel tube d, radius of outer fillet r which is located in the connection of sphere to cast steel tube, material strength f have remarkable effects on the bearing capacity of the joint. The results also show that with the increasing of parameter t, d, r, and f, the bearing capacity increases, and with the increasing of parameter D, the bearing capacity decreases.

Abstract: Abstract. The dynamic response of wind turbine tower under earthquake is analyzed by aid of the ANSYS program in this paper. To investigate the effects of simplification calculation models of blades and engines on calculation results, a blades-tower integrated finite element (FE) model and a mass-tower finite element (FE) model are established respectively. Then model analysis is discussed and the time history analysis of the system under the input of mean value earthquake record is carried out. The results show that seismic responses of a wind turbine tower are remarkable and seismic action may be the dominant factor in the design of wind turbine towers that located at a seismically active zone. Torsion effect of a tower is evident as a result of the impact of mass eccentricity. Bottom stress at the direction perpendicular to seismic waves is much bigger than that along it. It is also found that the blades-tower integrated finite element model can reflect more accurately the dynamic responses of the tower in the whole process of the earthquake and the “time-lag” effect by comparison, and these provide reliable reference to design and further research of towers.

Abstract: A method for determining the springing displacements and arch axis of old arch bridges without technical data is presented. By minimizing the difference between the arch axis predicted by the finite element model and the one obtained by assumed arch equation, the optimization problem is formulated and solved. Two numerical examples are given and the results are discussed.

Abstract: Structural damage detection by the Holder exponent receives much attention recently. Many investigations have been successfully applied to the crack identification, especially for the beam-type structures. However, a comprehensive analysis of the Holder exponent has been absent. Result in some conclusions had been drawn are unilateral. In this paper, the mode shapes of the clamped-clamped beams are analytical studied and a program calculating the Holder exponents of the mode shape signals with different damages is compiled with MATLAB. By comprehensively studying the Holder exponents of the clamped-clamped beams with cracks of different sizes, locations, and different order modes, a new phenomenon that the values of the Holder exponent vary with different locations of the crack is detected. The results also show that the Holder exponent decreases with the increase of the mode number. However, there are not obvious relations between the Holder exponent and the order of the mode for the whole beam locations.