Papers by Keyword: Nonlinear Analysis

Abstract: In November 2013 an experiment was carried out using the testing equipment called stand. During the experiment was loaded steel-fiber reinforced concrete foundation slab model. The stand measures deformation and monitors interaction between stress and deformation. The purpose of this paper is comparison of values measured during the experiment and results of numerical calculations based on FEM. The stress strain analysis of elastic halfspace by means of Gauss numerical integration and Jacobean of transformation is presented here. The objective of this paper is also improving and developing the soil-structure interaction analysis based on the experimental results and FEM.

Abstract: A new macro-element based on the equivalent frame approach is presented to analyze the nonlinear structural response of masonry panels under monotonic lateral loadings. A nonlinear elastic response is assumed for the masonry material and the sectional response of the beam is derived performing analytical integration. A two-node equilibrated force-based (FB) beam finite element (FE) is formulated. The FE is composed of a central flexible part, characterized by a no-tension constitutive relationship, and a lumped nonlinear shear hinge arranged in series, in order to capture the main flexural and shear nonlinear mechanisms characterizing the masonry panel response. Some applications on experimental prototypes are presented, showing a very satisfactory agreement between the numerical results and the experimental outcomes.

Abstract: Based on the spatial beam-column differential equations, the slope deflection equations considering second-order and bend-torsion coupling effect are established. The additional moment caused by torsion and bend deflection are taken into account. Then the finite element pattern of spatial beam-column considering the couple effect of torsion and bend is given. The tangent stiffness matrix and relevant program for nonlinear analysis are further obtained. By the nonlinear calculation and stability analysis of single component which has high accuracy or precise solution, the precision of the FEM model given in this paper is verified by comparing the results with that given in references.

Abstract: This paper presents the nonlinear dynamic analysis of the reinforced concrete building of nuclear power plant to the aircraft impact. The dynamic load is defined in time on the base of the simulation of the airplane impact considering real stiffness, masses, direction and velocity of the flight. The dynamic response is calculated in the system ANSYS using the transient nonlinear analysis solution method. The damage of the concrete wall is evaluated in accordance with the standard NDRC considering the spalling, scabbing and perforation effects. The simple and detailed calculations of the wall damage are compared.

Abstract: Based on the assumption of plane section, ideal elastic-plastic model of steel and the constitutive relations of concrete in Chinese Code for Design of Concrete Structures, numerical method is used to analyze the relationship of the axial force-moment-curvature on RC section. After dividing the normal section into strips, we adopt the secant stiffness iteration method (according to the results of each iteration, modify the secant stiffness through changing the elastic modulus of materials) to compile computer program. The results of the paper show a good agreement with those of the analytical method. Comparing with the analytical method, the numerical method of the paper can be wildly used in the application.

Abstract: Based on the wind tunnel experiment for aerostatic force of section model of Jianghai direct ship channel bridge of Hongkong-zhuhai-macau great bridge in its finished stage, one calculation program considering the geometric nonlinearity and aerostatic nonlinearity is prepared by using ANSYS parametric design language in order to calculate the nonlinear aerostatic response for long-span cable-stay bridges. Then, the FEA model of Jianghai direct ship channel bridge of Hongkong-zhuhai-macau great bridge in its finished stage is established to analyze the three-dimensional nonlinear aerostatic stability. And the aerostatic response with different position of bridge is also calculated. The research result indicates that the aerostatic instability can not occur in Jianghai direct ship channel bridge of Hongkong-zhuhai-macau great bridge in its finished stage. And, the max torsion deformation, transverse and vertical displacements of finished stage occur in the mid-span of each span and decrease gradually near to both sides.

Abstract: The performance-based engineering approach, as opposed to prescriptive rules of code-based design, is based on simulation of real structural behavior. Reliability of the expected performance state is assessed by using various methodologies based on finite element nonlinear static pushover analysis and specialized reliability software package. Reliability approaches that were considered included full coupling with an external finite element code based methods in conjunction with either first order reliability method or importance sampling method. The building considered in the actual study has been designed against seismic hazard according to the Moroccan code RPS2000.

Abstract: Based on the experiments of joint with exterior diaphragms between concrete-filled square steel tubular column and H-type steel beam under cyclic loading, with appropriate material stress-strain relations and failure criteria, the mechanical properties of this type of joint were researched by using ANSYS,finite element analyses were conducted under cyclic loading, the hysteretic and framework curves of this type joint between test and theoretical were researched. The study results showed that all specimens have good ductility and energy dissipation capacity. The story angle drift ductility ratios areμ=3.07~3.66,the elastic and elastic-plastic story angle drift are Φy=0.0041~0.0047 and Φu=0.0124~0.0172,and the equivalent viscous damping coefficients are he=0.26~0.35,which meet the needs of the current code for seismic design of building.

Abstract: In order to popularize the application of external prestressing technique in existing building green retrofits,this paper presents the compilation of nonlinear analysis program for externally prestressed beams based on both the geometrical nonlinearity type and the material nonlinearity type. Combined the static-load-experiment with 12 concrete beams prestressed with external tendons, the calculative results showed that this program matched relatively well with the experimental results.

Abstract: The paper addresses the issues of fire behavior of masonry walls made of traditional/historical component materials (bricks and mortar).There are reasons for coupling investigations on the residual mechanical properties to fire resistance data, aiming at a more complete knowledge of the behavior of a masonry member during and after fire exposure. The paper proposes a numerical approach via FEM to the problem of residual mechanical performance of load-bearing fire-separating masonry walls after insulation failure. The goal is to establish relationships between fire resistance ratings under exposure and decay in mechanical properties after exposure; the parameter of wall thickness is especially investigated. This is performed by means of FEM analysis, simulating a standard ISO 834 fire resistance test followed by a mechanical compressive failure test on each investigated type of wall. First, a preliminary transient heat flow analysis gives a numerical prediction of fire resistance after violation of I (Insulation) criterion; then, a staggered heat flow - stress analysis repeats the heating of the wall up to insulation failure and calculates the thermal strain accounting for cracking; finally, a 'cold' structural analysis in compression is performed on the thermally-deformed model after cooling. The comparison of numerical outcomes to available experimental information allows to judge the reliability of the numerical approach in reproducing the residual behavior of a masonry wall after fire exposure.