scholarly journals Global Buckling Investigation of the Flanged Cruciform H-shapes Columns (FCHCs)

2021 ◽  
Vol 11 (23) ◽  
pp. 11458
Author(s):  
Linfeng Lu ◽  
Di Wang ◽  
Zifan Dai ◽  
Tengfei Luo ◽  
Songlin Ding ◽  
...  
Keyword(s):  
Local Buckling ◽  
Design Codes ◽  
Buckling Mode ◽  
Primary Methods ◽  
Severe Problem ◽  
Compression Load ◽  
Current Design ◽  
Global Buckling ◽  
The Government ◽  
Hot Rolled

In China, increasing the application ratio of hot-rolled H-shapes has become a severe problem that the government, academia, and engineering circles must vigorously address. Research on reasonable hot-rolled H-shapes built-up columns is one of the primary methods. After reviewing the various combination columns in the existing research, the paper proposes the new flanged cruciform H-shapes columns (FCHCs) made of three hot-rolled H-shapes. Using comprehensive imperfections given by the design standard, GB50017-2017, the paper analyzes the global buckling of FCHCs subjected to the axial compression load. The global buckling factor obtained is compared with the current national design code. Comparative analysis of seventy-two specimens of Q345 and Q460 steel found that the global buckling mode of FCHCs was flexural bending buckling around the axis of symmetry, and global torsional buckling and local buckling did not occur. Furthermore, the corresponding column curves in current design codes overestimate the dimensionless buckling strength of the novel FCHCs. Therefore, designers need to drop a class to select the global buckling factor within a specific range. Finally, new column global buckling curves are proposed based on a non-linear fitting of the numerical results according to the current national design codes.

Stiffener Design and Analysis of SPSW Adapted to Bi-Directional Loading

2015 ◽  
Vol 744-746 ◽  
pp. 304-308
Author(s):  
Zong Jing Li ◽  
Gan Ping Shu ◽  
Jin Zhang ◽  
Li Hua Tan ◽  
Jiang Long Lu
Keyword(s):  
Steel Plate ◽  
Local Buckling ◽  
Design Criteria ◽  
Main Role ◽  
Design Codes ◽  
Steel Plate Shear Wall ◽  
Vertical Stiffness ◽  
Current Design ◽  
Overall Buckling

In truss-steel plate shear wall (SPSW) structures, the main role of SPSW is to provide horizontal and vertical stiffness for the system, which requires the SPSW capable of adapting to bi-directional loading. In order to satisfy the goal, stiffeners need to be added to the SPSW. In addition, openings are usually set within the SPSWs to meet certain architecture or utilization needs. Stiffener design criteria for such SPSW with or without opening are first derived according to the principle of yielding before buckling and local buckling before overall buckling. Then the deduced stiffener design criteria are compared with the current design codes. Finally the stiffener design recommendations are proposed for SPSW with or without opening adapting to bi-directional loading.

Study of Bending Capacity of an HPHT CRA-Lined Seamless Pipeline

2014 ◽  
Author(s):  
Cyprian Gil ◽  
Knut Tørnes ◽  
Per Damsleth
Keyword(s):  
Internal Pressure ◽  
Strain Localization ◽  
Local Buckling ◽  
Bending Moment ◽  
Design Criteria ◽  
Design Codes ◽  
Moment Capacity ◽  
Wide Range ◽  
Global Buckling ◽  
The Moment

A study has been performed to better understand ultimate bending moment and strain capacities of pipelines in relation to criteria defined in the design codes. An 18″ HPHT flowline was designed to undergo global buckling on uneven seabed and to resist trawl gear interference. The high temperature (155 degC) and pressure (300 bar) posed considerable design challenges for material selection and design criteria. A CRA-lined X60 CMn pipeline was selected for the project. The pipeline was of seamless manufacture for which the stress/strain characteristics are subject to the effect of Lüders bands. The DNV-OS-F101 code covers a wide range of D/t but does not specifically address Lüder’s material behaviour which could significantly reduce the bending moment capacity of pipe. The global buckling and trawl pull-over FE analysis results indicated the pipe was highly utilized, requiring excessive amounts of seabed intervention at great cost to meet the DNV LCC criteria. Detailed FE simulation of limit states for local buckling and strain localization of a 3D solid element pipe model was performed, with both Roundhouse and Lüders material properties, to investigate pipe capacity in relation to that stipulated by the design codes. The pipe moment capacity was established by obtaining the moment curvature relationship by bending the local pipe section subject to internal pressure until the maximum resistance was reached. Imperfections were introduced to initiate local buckling at the desired location. To determine strain concentration factors and strain localization, the effects of thickness changes and weld misalignment were also studied. The DNV OS-F101 LCC moment criterion formulation computes a decreasing moment capacity for increasing internal pressure. It has been suggested in the literature that this is correct for higher D/t but the criterion may be conservative for pipes with lower D/t. The combination of Lüders material with low D/t is not specifically addressed by any design code. Clarification of these aspects will provide a better understanding of the risk of failure for highly utilized seamless pipelines and allow for modified design criteria that will reduce seabed intervention costs. The results of the study showed that a higher bending moment criterion and associated strain criterion could be adopted for the design that allows for the higher initial strain caused by Lüder’s plateau. The ultimate bending moment capacity of low D/t pipe with Lüder’s material was found to be similar to that of Roundhouse material due to work hardening. In addition, it was demonstrated that the potential strength of the CRA liner could enhance the moment capacity of the seamless pipe.

Buckling analyses of double-shell octagonal lattice truss composite structures

2017 ◽  
Vol 52 (9) ◽  
pp. 1227-1237 ◽  
Author(s):  
Qianqian Sui ◽  
Changliang Lai ◽  
Hualin Fan
Keyword(s):  
Failure Mode ◽  
Composite Structures ◽  
Failure Modes ◽  
Local Buckling ◽  
Buckling Mode ◽  
One Dimensional ◽  
Load Carrying ◽  
Global Buckling ◽  
Buckling Failure ◽  
Equivalent Continuum

To reveal the compression failure modes of one-dimensional hierarchical double-shell octagonal lattice truss composite structures (DLTCSs), finite element modeling and equivalent continuum models were developed. DLTCS has three typical failure modes: (a) fracture of the strut, (b) global buckling, and (c) local buckling. Failure mode maps were constructed. It is found that column of long enough length will collapse at global buckling. When the column length decreases, the failure mode will turn to local buckling and strut fracture successively. Bay length greatly influences the buckling mode. Longer bay length could change the buckling mode from global buckling to local buckling. Compared with single-shell lattice truss composite structure, DLTCS has advantage in load carrying when the column fails at strut fracture or global buckling, while local buckling tolerance of DLTCS is smaller.

scholarly journals Buckling Behavior of Non-Retrofitted and FRP-Retrofitted Steel CHS T-Joints

2021 ◽  
Vol 11 (7) ◽  
pp. 3098
Author(s):  
Amin Yazdi ◽  
Maria Rashidi ◽  
Mohammad Alembagheri ◽  
Bijan Samali
Keyword(s):  
Compressive Loading ◽  
Local Buckling ◽  
Buckling Mode ◽  
T Joints ◽  
Hollow Section ◽  
Frp Composite ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Post Buckling ◽  
Circular Hollow Section

This paper aims to investigate the buckling behavior of circular hollow section (CHS) T-joints in retrofitted and non-retrofitted states under axial brace compressive loading. For this purpose, two types of analysis are carried out. The first one is evaluating the critical buckling load in various tubular joints, and the other one is investigating the post-buckling behavior after each buckling mode. More than 180 CHS T-joints with various normalized geometric properties were numerically modeled in non-retrofitted state to compute their governing buckling mode, i.e., chord ovalization, brace local, or global buckling. Then three joints with different buckling modes were selected to be retrofitted by fiber-reinforced polymer (FRP) patches to illustrate the improving effect of the FRP wrapping on the post-buckling performance of the retrofitted joints. In addition, FRP composite failures were investigated. The results indicate that the FRP retrofitting is able to prevent the brace local buckling, and that matrix failure is the most common composite failure in the retrofitted joints.

Using Controlled Global Buckling to Improve Buried Pipelines Performance Under Large Compressive Ground Displacements

2018 ◽  
Author(s):  
Ali Fathi ◽  
Onyekachi Ndubuaku ◽  
Samer Adeeb
Keyword(s):  
Boundary Conditions ◽  
Design Method ◽  
Local Buckling ◽  
Test Results ◽  
Buried Pipelines ◽  
Buckling Mode ◽  
Buried Pipes ◽  
Global Buckling ◽  
Novel Method ◽  
Simulated Field

This paper presents the basic concept and verification tests results of a novel method designed to prevent failures of buried pipelines subjected to compressive deformations which are usually caused by ground movements. In this method the boundary conditions of the buried pipes are modified by installing soft elements next to the pipe before backfilling. With the new boundary conditions, the pipe response under large compressive forces will be in form of a stable global buckling mode with a predefined deformed shape. This behavior prevents rapid increase in the compressive axial force that causes local buckling, wrinkling, and subsequent softening, and strain localization. By using this method, pipes can have an extended compressive hardening response that absorbs large compressive displacements. The evaluation of this concept and its performance level were studied through a series of lab tests on 4-1/2 inch pipe specimens under simulated field conditions. The test results confirmed the anticipated performance of this technique which can evolve into a design method.

ELASTIC BUCKLING OF THIN-WALLED CIRCULAR TUBES CONTAINING AN ELASTIC INFILL

2006 ◽  
Vol 06 (04) ◽  
pp. 457-474 ◽  
Author(s):  
M. A. BRADFORD ◽  
A. ROUFEGARINEJAD ◽  
Z. VRCELJ
Keyword(s):  
Axial Compression ◽  
A Priori ◽  
Local Buckling ◽  
Steel Tube ◽  
Transcendental Equation ◽  
Buckling Mode ◽  
Buckling Stress ◽  
Elastic Tubes ◽  
Thin Walled ◽  
Energy Formulation

Circular thin-walled elastic tubes under concentric axial loading usually fail by shell buckling, and in practical design procedures the buckling load can be determined by modifying the local buckling stress to account empirically for the imperfection sensitive response that is typical in Donnell shell theory. While the local buckling stress of a hollow thin-walled tube under concentric axial compression has a solution in closed form, that of a thin-walled circular tube with an elastic infill, which restrains the local buckling mode, has received far less attention. This paper addresses the local buckling of a tubular member subjected to axial compression, and formulates an energy-based technique for determining the local buckling stress as a function of the stiffness of the elastic infill by recourse to a transcendental equation. This simple energy formulation, with one degree of buckling freedom, shows that the elastic local buckling stress increases from 1 to [Formula: see text] times that of a hollow tube as the stiffness of the elastic infill increases from zero to infinity; the latter case being typical of that of a concrete-filled steel tube. The energy formulation is then recast into a multi-degree of freedom matrix stiffness format, in which the function for the buckling mode is a Fourier representation satisfying, a priori, the necessary kinematic condition that the buckling deformation vanishes at the point where it enters the elastic medium. The solution is shown to converge rapidly, and demonstrates that the simple transcendental formulation provides a sufficiently accurate representation of the buckling problem.

Factored axial compressive resistance of schifflerized angles

1991 ◽  
Vol 18 (6) ◽  
pp. 926-932 ◽  
Author(s):  
Seshu Madhava Rao Adluri ◽  
Murty K. S. Madugula
Keyword(s):  
Key Words ◽  
Design Method ◽  
Design Criteria ◽  
Design Practice ◽  
Buckling Mode ◽  
Flexural Buckling ◽  
Mode Of Failure ◽  
Current Design ◽  
Similarities And Differences ◽  
Compressive Resistance

The concept of schifflerization of 90° equal-leg angle is presented and its application in triangular-base latticed steel towers is explained. The similarities and differences between schifflerized angles and regular 90° angles are discussed. The current design practice for schifflerized angles is reviewed and its limitation is highlighted. A design method which includes the effect of the torsional-flexural buckling mode of failure is proposed. For ready use of designers, the factored axial compressive resistances of schifflerized angles are tabulated for both the present and proposed design methods. Key words: buckling, compressive resistance, design criteria, schifflerized angles, stability, standards, steel, struts, towers, guyed towers.

scholarly journals Compression Test on Cold-Formed Steel Built-Up Back-to-Back Channels Stub Columns

2011 ◽  
Vol 201-203 ◽  
pp. 2900-2903 ◽  
Author(s):  
Chui Huon Tina Ting ◽  
Hieng Ho Lau
Keyword(s):  
Compression Test ◽  
Failure Modes ◽  
Local Buckling ◽  
Effective Width ◽  
Test Results ◽  
Direct Strength Method ◽  
Cold Formed Steel ◽  
Stub Column ◽  
Hot Rolled ◽  
Stub Columns

Built-up sections are used to resist load induced in a structure when a single section is not sufficient to carry the design load for example roof trusses. In current North American Specification, the provision has been substantially taken from research in hot-rolled built-up members connected with bolts or welds [1]. The aim of this paper is to investigate on built-up back-to-back channels stub columns experimentally and theoretically using Effective Width Method and Direct Strength Method. Compression test was performed on 5 lipped channel and 5 back-to-back channels stub columns fabricated from cold-formed steel sheets of 1.2mm thicknesses. The test results indicated that local buckling is the dominant failure modes of stub columns. Therefore, Effective Width Method predicts the capacity of stub columns compared to Direct Strength Method. When compared to the average test results, results based on EWM are 5% higher while results based on DSM are 12% higher for stub column.

A Single Technically Consistent Design Formula for the Thickness of Cylindrical Sections Under Internal Pressure

2006 ◽  
Vol 129 (1) ◽  
pp. 211-215 ◽  
Author(s):  
John D. Fishburn
Keyword(s):  
Experimental Data ◽  
Internal Pressure ◽  
State Of The Art ◽  
Original Data ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Design Codes ◽  
Recent Developments ◽  
Current Design ◽  
Single Formula

Within the current design codes for boilers, piping, and pressure vessels, there are many different equations for the thickness of a cylindrical section under internal pressure. A reassessment of these various formulations, using the original data, is described together with more recent developments in the state of the art. A single formula, which can be demonstrated to retain the same design margin in both the time-dependent and time-independent regimes, is shown to give the best correlation with the experimental data and is proposed for consideration for inclusion in the design codes.

Experimental Study on Mechanical Behavior of Cold-Formed Steel Three Limbs Built-up Section Members

2010 ◽  
Vol 163-167 ◽  
pp. 651-654
Author(s):  
Tian Hua Zhou ◽  
Shao Feng Nie ◽  
Xiang Bin Liu ◽  
Guang Yi Li
Keyword(s):  
Experimental Study ◽  
Mechanical Behavior ◽  
Axial Compression ◽  
Local Buckling ◽  
Distortional Buckling ◽  
Torsional Buckling ◽  
Failure Characteristics ◽  
Compression Load ◽  
Cold Formed Steel ◽  
Flexural Torsional Buckling

18 specimens of cold-formed steel three limbs built-up section members are tested under axial compression load in this paper. The section forms are divided into two categories: A and B. Load-displacement (P-Δ) curves and failure characteristics of specimens are obtained. The results show that: As to section A members, the failure characteristics of LC, MC and SC series of specimens are flexural-torsional buckling, torsional buckling and distortional buckling, local buckling and distortional buckling. As to section B members, the failure characteristics of LC, MC series of specimens are flexural buckling, while local buckling and distortional buckling for members of SC series.

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