scholarly journals Beam-Column In-Plane Resistance Based on the Concept of Equivalent Geometric Imperfections

2016 ◽  
Vol 62 (4) ◽  
pp. 35-72 ◽  
Author(s):  
M.A. Giżejowski ◽  
R.B. Szczerba ◽  
M.D. Gajewski ◽  
Z. Stachura
Keyword(s):  
Structural Elements ◽  
Nonlinear Analyses ◽  
Geometric Imperfections ◽  
Beam Columns ◽  
Compression Members ◽  
Principal Axes ◽  
Buckling Resistance ◽  
The Stability ◽  
Hot Rolled ◽  
General Method

AbstractAssessment of the flexural buckling resistance of bisymmetrical I-section beam-columns using FEM is widely discussed in the paper with regard to their imperfect model. The concept of equivalent geometric imperfections is applied in compliance with the so-called Eurocode’s general method. Various imperfection profiles are considered. The global effect of imperfections on the real compression members behaviour is illustrated by the comparison of imperfect beam-columns resistance and the resistance of their perfect counterparts. Numerous FEM simulations with regard to the stability behaviour of laterally and torsionally restrained steel structural elements of hot-rolled wide flange HEB section subjected to both compression and bending about the major or minor principal axes were performed. Geometrically and materially nonlinear analyses, GMNA for perfect structural elements and GMNIA for imperfect ones, preceded by LBA for the initial curvature evaluation of imperfect member configuration prior to loading were carried out. Numerical modelling and simulations were conducted with use of ABAQUS/Standard program. FEM results are compared with those obtained using the Eurocode’s interaction criteria of Method 1 and 2. Concluding remarks with regard to a necessity of equivalent imperfection profiles inclusion in modelling of the in-plane resistance of compression members are presented.

scholarly journals Buckling resistance evaluation of steel beam-columns using refined General Method approach

2019 ◽  
Vol 262 ◽  
pp. 09010
Author(s):  
Zbigniew Stachura ◽  
Marian A. Gizejowski
Keyword(s):  
Steel Beam ◽  
Equation Approach ◽  
Resistance Evaluation ◽  
Beam Columns ◽  
Buckling Resistance ◽  
Eurocode 3 ◽  
Interaction Equation ◽  
Method Approach ◽  
General Method

Different aspects of Eurocode 3 General Method (GM) approaches are discussed in this paper. The purpose of present study is to improve the application of GM approach for both beam-columns without intermediate lateral-torsional restraints and with these restraints. The results from the proposed GM are compared with those from Eurocode 3-1-1 interaction equations according to Method 1 and Method 2. A better consistency between the developed GM approach and the Eurocode's interaction equation approach than Eurocode 3 GM approach is observed.

Design of single-angle compression members according to the Canadian standards

1996 ◽  
Vol 23 (3) ◽  
pp. 632-638 ◽  
Author(s):  
Murray C. Temple
Keyword(s):  
United States ◽  
Key Words ◽  
Failure Modes ◽  
The United States ◽  
Building Codes ◽  
Flow Chart ◽  
Structural Elements ◽  
Compression Members ◽  
Principal Axes ◽  
The Many

Although single-angle compression members, attached by one leg, appear to be very simple structural elements, they are amongst the most complex of structural elements to analyze and design. This is due to the end eccentricities and the fact that the principal axes of the angle do not coincide with the axis of the structure. The design of single-angle compression members, according to the Canadian standards, is not as straightforward as might be expected. There are numerous clauses to be considered in two standards. In some cases, all failure modes are not covered explicitly. The Canadian standards are examined and applied to the two generally accepted design approaches used in Canada and the United States. These approaches are (i) to ignore the end eccentricities and to treat the angle as a concentrically loaded member and (ii) to account for the end eccentricities by treating the angle as a beam–column. A flow chart is presented which will guide the designer through the many clauses that have to be considered in the two standards. Some suggestions are made which should help a practicing engineer design single-angle compression members that are attached by one leg. Key words: angles, buckling, building (codes), design.

On the Stability of Grillage Beams

1969 ◽  
Vol 13 (01) ◽  
pp. 23-31
Author(s):  
Pin-Yu Chang ◽  
F. C. Michelsen
Keyword(s):  
Boundary Conditions ◽  
Stability Criteria ◽  
Axial Loads ◽  
Compression Members ◽  
The Stability ◽  
General Method

A general method for obtaining the stability criteria of a grillage is presented. Axial loads in both sets of intersecting beams are considered. Properties and arrangements of beams are fairly arbitrary, as are permissible boundary conditions. However, the analysis is restricted to include only initially straight compression members.

Single-angle compression members welded by one leg to a gusset plate. I. Experimental study

1998 ◽  
Vol 25 (3) ◽  
pp. 569-584 ◽  
Author(s):  
Murray C Temple ◽  
Sherief SS Sakla
Keyword(s):  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Structural Elements ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Compression Members ◽  
Principal Axes ◽  
Load Carrying ◽  
A Minor ◽  
Compressive Resistance

Single-angle compression members are structural elements that are very difficult to analyze and design. These members are usually attached to other members by one leg only. Thus the load is applied eccentrically. To further complicate the problem the principal axes of the angle do not coincide with the axis of the frame of which the angle is a part. Although it is known that the end conditions affect the load-carrying capacity of these members, procedures have not been developed to account for this. The main objective of this research is to obtain a better understanding of the behaviour and load-carrying capacity of single-angle compression members welded by one leg to a gusset plate fixed to a rigid support. The effects of the gusset plate width, thickness, and the unconnected length were studied. It was determined that the finite element method can be used, with a reasonable degree of accuracy, to predict the behaviour and load-carrying capacity of these members. It was found that the thickness and width of the gusset plate significantly affect the load-carrying capacity, but the unconnected length has only a minor effect.Key words: angles, buckling, building (codes), columns (structural), compressive resistance, design, gusset plates.

Considerations for the design of single-angle compression members attached by one leg

1996 ◽  
Vol 23 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Murray C. Temple ◽  
Sherief S. S. Sakla
Keyword(s):  
Key Words ◽  
Design Procedure ◽  
Building Codes ◽  
Experimental Results ◽  
Structural Elements ◽  
Structural Members ◽  
Design Procedures ◽  
Compression Members ◽  
Principal Axes ◽  
Complex Structural

Angles appear to be one of the simplest of structural elements. Connections, bolted or welded, are easy to make. Despite this, angle compression members are among the most complex structural members to analyze and design. This is because of the end eccentricities of the end connections and because the principal axes of a single angle do not coincide with the axis of the frame or truss of which the angle is a part. Some experimental results are compared with the two generally accepted design procedures. These results are discussed, and hopefully this will aid the designer in selecting a design procedure. Key words: angles, buckling, building (codes), design.

Stability and Frequency Response of Top-Tensioned Risers and SCR’s: The L/D Ratio in Perspective

2009 ◽  
Author(s):  
William Todd
Keyword(s):  
Dynamic Behavior ◽  
Load Distribution ◽  
Analytic Solution ◽  
Mode Shapes ◽  
Structural Elements ◽  
Close Coupling ◽  
Beam Columns ◽  
End Conditions ◽  
Slender Beams ◽  
The Stability

Stability is closely linked to the dynamic behavior of risers and SCR’s. This paper reviews the L/D criterion as used to categorize offshore structural elements and places this criterion in perspective when used in VIV calculations to compare slender beams, beam-columns and cable behavior to anticipated results for top-tensioned risers with like L/D ratios. The stability of beam-columns with various end conditions and loadings are compared to that of an in-service 2400m top-tensioned riser. An analytic solution for the frequencies and mode shapes of top-tensioned risers at varying top-tension is given and factors which influence the dynamic behavior detailed. The analysis demonstrates that loads and representation of the load distribution are vital to obtaining valid results. Close-coupling of displacement and slope with loading are essential to the analysis. Results are shown of the effects of varying top-tension factor (TTF) on the stability and dynamic response of risers and SCR’s.

Preparation and Characterization of β-glucosidase Films for Stabilization and Handling in Dry Configurations

2020 ◽  
Vol 21 (8) ◽  
pp. 741-747
Author(s):  
Liguang Zhang ◽  
Yanan Shen ◽  
Wenjing Lu ◽  
Lengqiu Guo ◽  
Min Xiang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Protein Function ◽  
Protein Stabilization ◽  
Functional Protein ◽  
Elongation At Break ◽  
Gelatin Films ◽  
The Stability ◽  
And Function ◽  
General Method

Background: Although the stability of proteins is of significance to maintain protein function for therapeutical applications, this remains a challenge. Herein, a general method of preserving protein stability and function was developed using gelatin films. Method: Enzymes immobilized onto films composed of gelatin and Ethylene Glycol (EG) were developed to study their ability to stabilize proteins. As a model functional protein, β-glucosidase was selected. The tensile properties, microstructure, and crystallization behavior of the gelatin films were assessed. Result: Our results indicated that film configurations can preserve the activity of β-glucosidase under rigorous conditions (75% relative humidity and 37°C for 47 days). In both control films and films containing 1.8 % β-glucosidase, tensile strength increased with increased EG content, whilst the elongation at break increased initially, then decreased over time. The presence of β-glucosidase had a negligible influence on tensile strength and elongation at break. Scanning electron-microscopy (SEM) revealed that with increasing EG content or decreasing enzyme concentrations, a denser microstructure was observed. Conclusion: In conclusion, the dry film is a promising candidate to maintain protein stabilization and handling. The configuration is convenient and cheap, and thus applicable to protein storage and transportation processes in the future.

scholarly journals Asymmetry underlies stability in power grids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ferenc Molnar ◽  
Takashi Nishikawa ◽  
Adilson E. Motter
Keyword(s):  
Symmetry Breaking ◽  
Real World ◽  
Power Grids ◽  
Stable Operation ◽  
World Systems ◽  
Symmetric State ◽  
Network Systems ◽  
Additional Improvement ◽  
The Stability ◽  
General Method

AbstractBehavioral homogeneity is often critical for the functioning of network systems of interacting entities. In power grids, whose stable operation requires generator frequencies to be synchronized—and thus homogeneous—across the network, previous work suggests that the stability of synchronous states can be improved by making the generators homogeneous. Here, we show that a substantial additional improvement is possible by instead making the generators suitably heterogeneous. We develop a general method for attributing this counterintuitive effect to converse symmetry breaking, a recently established phenomenon in which the system must be asymmetric to maintain a stable symmetric state. These findings constitute the first demonstration of converse symmetry breaking in real-world systems, and our method promises to enable identification of this phenomenon in other networks whose functions rely on behavioral homogeneity.

Innovative Use of Profiled Steel Plates for Seismic Structural Performance

2005 ◽  
Vol 8 (3) ◽  
pp. 247-257 ◽  
Author(s):  
Y. Fukumoto ◽  
T. Takaku ◽  
T. Aoki ◽  
K. A. S. Susantha
Keyword(s):  
Numerical Analysis ◽  
Seismic Performance ◽  
Structural Design ◽  
Design Method ◽  
Steel Plates ◽  
Structural Performance ◽  
Cyclic Testing ◽  
Beam Columns ◽  
Bridge Bents ◽  
Hot Rolled

This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

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