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 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.

Load Carrying Capacity and Ductility of CFRP-Reinforced Earthquake Waste Filled Circular Steel Tube Columns

2012 ◽  
Vol 463-464 ◽  
pp. 234-238 ◽  
Author(s):  
Dong He ◽  
Jiang Feng Dong ◽  
Shu Cheng Yuan ◽  
Qing Yuan Wang
Keyword(s):  
Carrying Capacity ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Load Carrying Capacity ◽  
Aggregate Concrete ◽  
Cfrp Sheets ◽  
Circular Steel Tube ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

In order to significantly increase not only the load carrying capacity but also the ductility of the steel tube columns filled with recycled aggregate concrete from the earthquake waste, two different strengthening methods by using externally bonded of carbon fibre reinforced polymer (CFRP) to strengthened the columns was proposed. Composite columns of CFRP reinforced and steel circular steel tube columns are studied in this study. The aims were to study the contribution of the CFRP sheets applied in enhancing the load carrying capacity and ductility of the steel tube columns with different concrete type, normal concrete and recycled aggregate concrete. The results demonstrate that the ultimate load carrying capacity and ductility of the steel tube columns filled with recycled aggregate concrete can be increased satisfactorily by full wrapping and partial wrapping arrangement of CFRP sheets. Moreover, stiffness of the columns strengthened was also increased greatly due to the restraining effect offered by CFRP and the full wrapping arrangement is better than the partial wrapping arrangement in enhancing the stiffness and the load carrying capacity.

scholarly journals Waveguide analysis for ultrasonic medical instruments (comparison of different methods)

2018 ◽  
Vol 226 ◽  
pp. 04007
Author(s):  
Yuri V. Grigoryev ◽  
Pyae Phyo Aung
Keyword(s):  
Medical Instrument ◽  
Excitation Frequency ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Transition Matrices ◽  
Runge Kutta Method ◽  
Straight Line ◽  
Different Types ◽  
Waveguide Design ◽  
Line Concentrator

Transition matrices are derived on the basis of some analytical solutions for a number of waveguides. Initial parameters method is used to analyze the waveguide longitudinal oscillations. This paper contains a comparative analysis of different types of concentrators. The waveguide design scheme presents a straight bar of variable cross-section with different boundary conditions. For given concentrator arrangements, the amplitude axial displacements and longitudinal forces in the ultrasonic medical instrument (UMI) are calculated for a certain excitation frequency. Numerical method for calculation of eigenfrequencies and eigenmodes of the ultrasonic medical instrument (UMI) waveguide is presented. Analysis of the cantilever straight-line concentrator based on the methods of transition matrices and numerical integration by the Runge-Kutta method are under comparison. Sufficient agreement of the results is demonstrated.

scholarly journals Experimental and Numerical Analysis of Large-Scale Circular Concrete-Filled Steel Tubular Columns with Various Constructural Measures under High Axial Load Ratios

2018 ◽  
Vol 8 (10) ◽  
pp. 1894 ◽  
Author(s):  
Lidong Zhao ◽  
Wanlin Cao ◽  
Huazhen Guo ◽  
Yang Zhao ◽  
Yu Song ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Axial Load ◽  
Large Scale ◽  
Steel Tube ◽  
Test Results ◽  
Welded Steel ◽  
Axial Forces ◽  
Circular Steel Tube ◽  
Cfst Columns

To investigate the effect of constructional measures (including horizontal and vertical stiffeners, rebar cages, embedded steel tubes, and cavity welded steel plates) under high axial load ratios on the seismic performance of concrete-filled steel tubular (CFST) columns, quasi-static tests for six large-scale CFST columns with various constructional measures are performed. All specimens are subjected to identical axial forces. The failure mode, hysteresis characteristics, bearing capacity, stiffness degradation, ductility, and energy dissipation of specimens are analyzed. The study shows that the horizontal stiffener delays the occurrence and severity of column base buckling, the vertical stiffener improves the bending resistance capacity and initial stiffness of the member, the rebar cage improves the ductility, and the embedded circular steel tube significantly improves the member’s bearing capacity, ductility, and energy dissipation. When an internal circular steel tube and cavity welded steel plate are applied in tandem, the section steel ratio increases by 4.42% and the bearing capacity improves by 42.72%. A finite element model is created to verify test results, and simulation results match the test results well.

scholarly journals SERIES SOLUTION OF LARGE DEFORMATION OF A BEAM WITH ARBITRARY VARIABLE CROSS SECTION UNDER AN AXIAL LOAD

2009 ◽  
Vol 51 (1) ◽  
pp. 10-33 ◽  
Author(s):  
SHIJUN LIAO
Keyword(s):  
Differential Equations ◽  
Cross Section ◽  
Axial Load ◽  
Nonlinear Differential Equations ◽  
Variable Cross Section ◽  
Variable Coefficients ◽  
Buckling Load ◽  
Moment Of Inertia ◽  
Variable Cross ◽  
Critical Buckling Load

AbstractA general analytic approach is proposed for nonlinear eigenvalue problems governed by nonlinear differential equations with variable coefficients. This approach is based on the homotopy analysis method for strongly nonlinear problems. As an example, a beam with arbitrary variable cross section acted on by a compressive axial load is used to show its validity and effectiveness. This approach provides us with great freedom to transfer the original nonlinear buckling equation with variable coefficients into an infinite number of linear differential equations with constant coefficients that are much easier to solve. More importantly, it provides us with a convenient way to guarantee the convergence of solution series. As an example, the beam displacement and the critical buckling load can be obtained for arbitrary variable cross sections. The influence of nonuniformity of moment of inertia is investigated in detail and the optimal distributions of moment of inertia are studied. It is found that the critical buckling load of a beam with the optimal distribution of moment of inertia can be approximately 21–22% larger than that of a uniform beam with the same average moment of inertia. Mathematically, this approach is rather general and thus can be used to solve many other linear/nonlinear differential equations with variable coefficients.

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.

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