scholarly journals Experimental Investigation of Connection Details on the Cyclic Performance of All-steel Tubular Buckling Restrained Braces

2020 ◽  
Author(s):  
Seayf Allah Hemati ◽  
Ali Kheyroddin ◽  
Mohammad Ali Barkhordari Bafghi
Keyword(s):  
Compressive Load ◽  
Tensile Load ◽  
Variable Cross Section ◽  
Steel Tube ◽  
Transitional Region ◽  
Variable Cross ◽  
Load Bearing ◽  
The Core ◽  
Buckling Restrained Braces ◽  
Geometrical Defects

To eliminate the geometrical defects and to reduce the damage caused by out-off-plane rotation of the end portion of the conven-tional buckling restrained braces, as well as introducing a new way to facilitate the construction and installation process, the exper-imental behavior of 5 proposed specimens as new type of all-steel tubular buckling restrained braces (AST-BRB) under cyclic axial loads was studied.The proposed specimens consist of a steel tube as a load bearing member (core), which is placed inside a larger tube as a buckling restraining member (pod). At the two ends of the core member, different end details and connection (compared to the common BRBs) are provided as the elastic transitional region. The performance of the specimens were evaluated based on indices, such as damage mode, repeatable behavior, adjusted strength factors, load-bearing capacity, and cumulative inelastic displacement.The evaluation of the results indicated that, the specimens, which welded variable cross-section steel lids at both ends of the core, have superior seismic performance. The superior specimens, for all cycles with larger displacements of the yielding displacement, exhibited a stable hysteresis behavior in bearing of cyclic loads. The bearing pressure was about 1.07 times greater than the tensile load. The cumulative inelastic axial displacements of these specimens is at least 209 times of their yield displacement. Meanwhile, they can tolerate at least 140 % compressive load and 10 % greater tension loads relative to the nominal capacity of the core individual.

Research on Concrete-Filled Rectangular Steel Tube Stiffeners and Axial Compression Bearing Capacity

2014 ◽  
Vol 1065-1069 ◽  
pp. 1092-1096 ◽  
Author(s):  
Gao Cheng ◽  
Yong Jian Liu ◽  
Lei Jiang
Keyword(s):  
Bearing Capacity ◽  
Mechanical Performance ◽  
Compressive Load ◽  
Steel Tube ◽  
Simple Construction ◽  
The Core ◽  
Steel Bar ◽  
Stiffening Ribs ◽  
Reinforcement Measures ◽  
Core Concrete

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.

scholarly journals Determination of Critical Load in a Nonuniform Circular Steel Column under the Eccentric Axial Load

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Stanislav Kotšmíd ◽  
Chang-Hung Kuo ◽  
Pavel Beňo
Keyword(s):  
Critical Load ◽  
Axial Load ◽  
Variable Cross Section ◽  
Steel Tube ◽  
Variable Cross ◽  
Runge Kutta Method ◽  
Circular Steel Tube ◽  
Load Carrying ◽  
Loading Tests ◽  
Different Diameters

The purpose of this paper is to determine a critical load for a nonuniform circular steel tube under eccentrically axial load. The circular tube has variable cross section at flattened ends with existing holes used for connection between members. Three different cases of eccentricities are studied with the drilled holes either on the same side or on the opposite side of column axis. The critical load is calculated from the differential equation of deflection curve which is solved by the power series and Runge-Kutta method. In addition, the loading tests were performed on a total of 180 specimens with different diameters, slenderness, and connection. The calculated results are compared and shown in a good agreement with those obtained from the experimental results. The results also show that the critical load decreases rapidly even at a small value of eccentricity and thus may have a significant effect on the load-carrying capacity.

scholarly journals Design and Compressive Behavior of a Photosensitive Resin-Based 2-D Lattice Structure with Variable Cross-Section Core

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 186 ◽  
Author(s):  
Shuai Li ◽  
Jiankun Qin ◽  
Bing Wang ◽  
Tengteng Zheng ◽  
Yingcheng Hu
Keyword(s):  
Analytical Model ◽  
Cross Section ◽  
Lattice Structure ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Compressive Response ◽  
The Core ◽  
Photosensitive Resin ◽  
Lattice Core ◽  
Material Utilization

This paper designed and manufactured photosensitive resin-based 2-D lattice structures with different types of variable cross-section cores by stereolithography 3D printing technology (SLA 3DP). An analytical model was employed to predict the structural compressive response and failure types. A theoretical calculation was performed to obtain the most efficient material utilization of the 2-D lattice core. A flatwise compressive experiment was performed to verify the theoretical conclusions. A comparison of theoretical and experimental results showed good agreement for structural compressive response. Results from the analytical model and experiments showed that when the 2-D lattice core was designed so that R/r = 1.167 (R and r represent the core radius at the ends and in the middle), the material utilization of the 2-D lattice core improved by 13.227%, 19.068%, and 22.143% when n = 1, n = 2, and n = 3 (n represents the highest power of the core cross-section function).

Wrinkling Identification and Wrinkle Distribution of a Tube in Hydroforming with Radial Crushing

2011 ◽  
Vol 291-294 ◽  
pp. 662-667 ◽  
Author(s):  
Xiao Feng Liu ◽  
Lian Fa Yang ◽  
Yu Xian Zhang
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Hydraulic Pressure ◽  
Variable Cross ◽  
Element Simulation ◽  
Middle Cross Section ◽  
The Cross ◽  
Cross Section Profile

Hollow parts with variable cross-section are widely used in the area of automotive and aerospace industries due to their excellent properties. Wrinkling is one of the most common forms of instability in the process of manufacturing the parts. The minimum curvature of the cross-section profile of bugled workpieces is proposed in this paper to as a wrinkling indicator to characterize the form and extent of the wrinkle. The wrinkle distribution of 1Cr13Mn9Ni1N stainless steel tube in hydroforming with radial crushing under linear and constant hydraulic pressures is analyzed and the influence of the bulging methods on the wrinkling is investigated via finite element simulation. The results indicate that wrinkling under constant hydraulic pressure is more obvious than that under linear one, wrinkling in hydroforming with radial crushing is more serious than that in free hydro-bugling, wrinkling on the cross-section away from the middle cross-section is more distinct and the wrinkling on the side edge is obvious than that on the bottom of the bugled workpiece.

Experimental Study on Short Steel Tube Columns Filled with Recycled Large Aggregate-Self Compacting Concrete Subjected to Compression

2021 ◽  
Vol 13 (5) ◽  
pp. 991-1002
Author(s):  
Jian-Chao Wang ◽  
Zhong-Zheng Guan ◽  
Zi-Ming Qiu ◽  
Wei Hou
Keyword(s):  
Particle Size ◽  
Mechanical Characteristics ◽  
Steel Tube ◽  
Portland Cement Concrete ◽  
Self Compacting Concrete ◽  
Large Aggregate ◽  
Aggregate Concrete ◽  
Load Bearing ◽  
The Core ◽  
Short Columns

The mechanical characteristics of recycled large aggregate concrete show poorer performance than that of Portland-cement concrete due to the internal defects of recycled large aggregate (RLA). To improve the mechanical characteristics of recycled large particle size aggregate concrete, the recycled large aggregate Self-Compacting Concrete filled steel tube (RLA-SCCFST) is proposed. The external steel tube can not only keep the core recycled large aggregate concrete in the three-dimensional state of stress, but also prevent the crack expansion of the core recycled large aggregate concrete. RLA-SCCFST subjected to compression is studied experimentally. The compression failure tests use 20 specimens of circular section short column with different steel content rate, particle size of RLA, strength of RLA, strength of SCC, and eccentricity of the load. The influence of different factors on mechanical characteristics of RLA-SCCFST short cylindrical components subjected to compression is analyzed. The results indicate that the load-bearing performance of RLA-SCCFST short columns increases following with the augmentation of RLA particle size, strength of RLA particle size, strength of SCC and steel content rate. The load-bearing performance of RLA-SCCFST short columns reduced with the augmentation of the load eccentricity. And the experimental results are in high coincidence with those calculated by different formulas.

AN ANALYTIC APPROACH FOR EXACTLY DETERMINING CRITICAL LOADS OF BUCKLING OF NONUNIFORM COLUMNS

2012 ◽  
Vol 12 (04) ◽  
pp. 1250027 ◽  
Author(s):  
Y. HUANG ◽  
X.-F. LI
Keyword(s):  
Linear Equations ◽  
Compressive Load ◽  
Variable Cross Section ◽  
Analytic Approach ◽  
Variable Cross ◽  
System Of Linear Equations ◽  
Buckling Loads ◽  
Buckling Instability ◽  
Fixed Weight ◽  
Suboptimal Design

This paper studies buckling instability of columns with variable bending stiffness subjected to an axially compressive load. An analytic approach has been presented to determine critical buckling loads of a nonuniform column with or without continuous elastic restraint along its length. We transform this problem into a Fredholm equation, and then to a system of linear equations. The desired buckling loads can be easily obtained by solving the least positive eigenvalue of the resulting system. The validity and efficiency of the method is confirmed by comparing our numerical results with those available. The influences of variable cross-section or elastic restraint stiffness on the buckling loads of a simply-supported column are analyzed. A suboptimal design of a tapered cylindrical bar with fixed weight is given. The present results are of benefit to the optimal design of beam/column structures.

Experimental Research of Bottom Chord Splice Joints with Variable Cross-Section in Steel Roof Truss

2011 ◽  
Vol 105-107 ◽  
pp. 1065-1068
Author(s):  
Hong Xia Wan ◽  
De Xu Yan ◽  
Xiao Ping Wang
Keyword(s):  
Cross Section ◽  
Experimental Research ◽  
Failure Modes ◽  
Variable Cross Section ◽  
Steel Tube ◽  
Engineering Practice ◽  
Variable Cross ◽  
Test Setup ◽  
Roof Truss ◽  
Tension Capacity

A workshop’s roof is designed to use steel tube trusses with the span of 24m. There are three kinds of variable cross-section splice joints of the roof truss bottom chord. Nine splice joint specimens, three for each kind, were tested to obtain their tension capacity and failure modes. A special test setup is designed to introduce the tension load to the splice joint specimen. The paper detailed introduced the test setup and method, discussed the failure load and failure mode of the joints. Experimental research indicated that the bottom chord splice joint with variable cross-section of the roof is safe, reliable, having high bearing capacity. The research also validated the correctness of the design and calculation, and provided the basis for the application of such joints in the engineering practice.

Boundary element method in numerical study of three-dimensional Stokes flows in channels of arbitrary shape

2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Periodic Flows ◽  
Element Method

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.

Longitudinal oscillation of a rod with a variable cross section

2019 ◽  
Vol 14 (2) ◽  
pp. 138-141
Author(s):  
I.M. Utyashev
Keyword(s):  
Cross Section ◽  
Natural Frequencies ◽  
Liouville Problem ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Independent Functions ◽  
The Cross ◽  
The Right

Variable cross-section rods are used in many parts and mechanisms. For example, conical rods are widely used in percussion mechanisms. The strength of such parts directly depends on the natural frequencies of longitudinal vibrations. The paper presents a method that allows numerically finding the natural frequencies of longitudinal vibrations of an elastic rod with a variable cross section. This method is based on representing the cross-sectional area as an exponential function of a polynomial of degree n. Based on this idea, it was possible to formulate the Sturm-Liouville problem with boundary conditions of the third kind. The linearly independent functions of the general solution have the form of a power series in the variables x and λ, as a result of which the order of the characteristic equation depends on the choice of the number of terms in the series. The presented approach differs from the works of other authors both in the formulation and in the solution method. In the work, a rod with a rigidly fixed left end is considered, fixing on the right end can be either free, or elastic or rigid. The first three natural frequencies for various cross-sectional profiles are given. From the analysis of the numerical results it follows that in a rigidly fixed rod with thinning in the middle part, the first natural frequency is noticeably higher than that of a conical rod. It is shown that with an increase in the rigidity of fixation at the right end, the natural frequencies increase for all cross section profiles. The results of the study can be used to solve inverse problems of restoring the cross-sectional profile from a finite set of natural frequencies.

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