Advanced Materials Research Vols. 1065-1069

Abstract: Concrete is a brittle material which cracks under the tension and pulverized when the compressive stress exceeds the ultimate compressive strength. Confined concrete performs better than that of concrete without confinement in resisting penetration. Based on the Griffith strength theory, a quasi-static cylindrical cavity expansion model for the penetration of steel-tube-confined concrete targets is proposed. Numerical results show that ratio of tube wall thickness to tube radius significantly effects cavity expansion stress, which is in proportion to the former ratio. The results are in good agreement with the cavity expansion process.

Abstract: In this paper, systemic FSI numerical simulations for wind-induced dynamic response of saddle-shaped tension membrane structures are performed using ADINA software, and the effects of some parameters such as inlet velocity, wind direction, span, rise-span ratio, tension stiffness and pre-stress of tension membrane are considered. The flow is modeled with the incompressible viscous Navier-Stokes equations and the standard κ-ω turbulence model, and the membrane is assumed as isotropic-linear-elastic material with large displacement and small strain. The rules of FSI numerical simulation for wind-induced dynamic responses of saddle-shaped tension membrane structures are summarized and the wind-induced dynamic coefficients and the wind pressure distribution coefficients are obtained which can be used in the design of membrane structures.

Abstract: Engineering examples and finite element structural analysis software SATWE was used to calculate by adjusting the shear wall thickness and grade to study the dynamic characteristics of concrete structures; analysis of seismic shear, natural vibration cycles, maximum interlayer displacement angle, lateral displacement stiffness to weight ratio and shear weight ratio of these parameters change rules, resulting in changes in shear wall thickness greater impact on shear wall amount.

Abstract: This paper is concerned with the analytical solution to lateral equivalent flexural rigidity for fiber-reinforced top-hat stiffened composite plate subjected to pure bending. The plate is divided into three parts consist of single-laminate, double-laminate and hat-laminate. After computing equivalent flexural rigidity of the three parts respectively, the overall rigidity is calculated based on the equality of relative rotation angle. An example has been adopted for analytical calculation and then been modeled by finite elements method. A comparison was made to verify the validity of analytical method.

Abstract: This paper presents an investigation on the nonlinear dynamic response of piezoelectric beam reinforced with boron nitride nanotubes (BNNTs) under combined electro-thermo-mechanical loadings. By employing nonlinear strain and utilizing piezoelectric theory, the constitutive relations of the piezoelectric beam reinforced with BNNTs are established. Then the dynamic governing equations of the structure are derived through variational principle and resolved by applying the finite difference method. In numerical examples, the effects of geometric nonlinear, voltage etc. on the nonlinear dynamic response of piezoelectric beam reinforced with BNNTs are discussed.

Abstract: Reliability analysis and reliability-based design optimization of large scale box-girder structural system is an interesting topic in the field of structural design. Structural resistance, loading, plating thickness and cross-sectional area of beam are considered as stochastic variables. Safety margin equations of both beam and plate element are constructed. Since the safety margin equations are implicit function of random variables, the stochastic finite element method (SFEM) is adequate for sensitivity analysis. The advanced first order second moment (AFOSM) method is used to calculate the safety indices of structural components. In addition to this, branch and bound method is used to identify the dominant failure paths. Probabilistic Network Evaluation Technique (PNET) method is used to assess failure probability of structural system. The optimization problem of structure is formulated as a nonlinear programming problem that aims at minimizing structural weight with constraints on reliability and range constraints of design variables. An optimum vector algorithm is applied to solve the optimization problem. One illustrative example is carried out to elucidate present process of reliability assessment and reliability-based design optimization.

Abstract: Concrete-filled rectangular steel tube four sides restraint effect on the core concrete was weaker than the corner, which made the effect not significant. The paper studied a new kind of stiffening rib –PBL stiffener to strengthen restraint effect of concrete-filled rectangular steel tube , and evaluated its advantages compared with other stiffening ribs. 9 PBL stiffened concrete-filled rectangular steel tube columns under axial compressive load were tested. It also collected the test with other stiffened rids, such as straight ribs, binding bars, knee brace, steel reinforcement cage, steel bar stiffeners, saw tooth shaped stiffeners, stitching straight stiffeners and no rib concrete filled rectangular steel tube to compare. It evaluated increasing coefficient of bearing capacity by stiffening ribs. The results showed that: the PBL stiffeners and binding bar of concrete-filled rectangular steel tube bearing capacity was greater than other reinforcement measures by more than 20%; PBL stiffener could be a new prominent type of stiffener because of its excellent mechanical performance and simple construction.

Abstract: H-beam is usually used as column structure of single industrial workshop, steel column will inevitably encounter lateral impact of lifting weights or factory vehicle in the process of daily production, causing its defects in material and geometry, thus the change of axial bearing capacity.This aratical takes H-shaped steel column of a factory as the research object, establishes its residual bearing capacity theory of finite element analysis model in different situations under the impact using ABAQUS software platform, discusses the load parameters analysis in axial force-impac and Launches the functional relation between axial compression ratio and impact energy, providing a basis for assessing the residual loading capacity of such members after the impact.

Abstract: location axis, joints, force-transforming plates, carrying capacityAbstract: Steel structure has been widely used all over the world. In actual construction process, steel structure inevitably has initial defects, which may have bad influences on its performance. Three groups of specimens were designed in this paper to compare the performance of rigid joints transferring forces outside box columns to that of perfect traditional joints and that of traditional joints with uniaxial and biaxial deviation of column's location axis by finite element method program ANSYS. From the analysis of stiffness, yielding capacity, and ultimate carrying capacity, the impact of force-transforming plates can be evaluated. The adding force-transforming plates were helpful to reduce the influence from column imperfect.

Abstract: Buckling-Restrained Brace (BRB) in China, Taiwan, and Japan, as a kind of hysteretic damper has been installed into steel frame structure; In the United States, however, it has been installed into the hinge-connected steel framework, as the main seismic element in order to add lateral stiffness and strength.This paper according to the design codes of frame structure in China, Japan and the United States,establishes the research model based 0n the typical steel frame form of China, Japan, and the US.The main research parameters of the model are horizontal force sharing ratio of BRB (β) and frame strength of BRB (CB)。Through the steel consumption,the relationship of story drift and story shear, the formation of plastic hinge of the design model,it compares the steel frame seismic design method of China, Japan and the United States.The steel consumption of frame is related to the strength of the frame, but has nothing to do with the frame structure form;The plastic hinge of each model focused mainly on the BRB,reflecting the overall mechanism; As to seismic design requirements, the Japanese codes are stricter, codes of China and the United States is relatively close.