scholarly journals Design Tools for Bolted End-Plate Beam-to-Column Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Giusy Terracciano ◽  
Gaetano Della Corte ◽  
Gianmaria Di Lorenzo ◽  
Raffaele Landolfo
Keyword(s):  
Moment Frames ◽  
Initial Stiffness ◽  
Practical Applications ◽  
Geometrical Properties ◽  
Component Method ◽  
End Plate ◽  
Joint Characteristics ◽  
Theoretical Predictions ◽  
Analytical Tools ◽  
Approximate Equations

Predicting the response of beam-to-column joints is essential to evaluate the response of moment frames. The well-known component method is based on a mechanical modelling of the joint, through joint subdivision into more elementary components subsequently reassembled together to obtain the whole joint characteristics. Significant advantages of the component method are the following: (i) the mechanics-based modelling approach; (ii) the easier general characteristics of components. However, the method is commonly perceived by practicing engineers as being too laborious for practical applications. Within this context, this paper summarizes the results of a theoretical study aiming to develop simplified analysis tools for bolted end-plate beam-to-column joints, based on the Eurocode 3 component method. The accuracy of the component method was first evaluated, by comparing theoretical predictions of the plastic resistance and initial stiffness with corresponding experimental data collected from the available literature. Subsequently, design/analysis charts were developed through a parametric application of the component method by means of automatic calculation tools. They are easy and quick tools to be used in the first phases of the design process, in order to identify joint configurations and geometrical properties satisfying specified joint structural performances. The parametric analysis allowed also identifying further simplified analytical tools, in the form of nondimensional equations for predicting quickly the joint structural properties. With reference to selected geometries, the approximate equations were verified to provide sufficiently accurate predictions of both the stiffness and the resistance of the examined beam-to-column joints.

Experimental Investigation of Retrofitted Extended End-Plate Connections

2013 ◽  
Vol 284-287 ◽  
pp. 1330-1333
Author(s):  
Poi Ngian Shek ◽  
M.Md. Tahir ◽  
Cher Siang Tan ◽  
Arizu Sulaiman
Keyword(s):  
Experimental Tests ◽  
Horizontal Shear ◽  
Initial Stiffness ◽  
Component Method ◽  
End Plate ◽  
Theoretical Predictions ◽  
Extended End Plate ◽  
Plate Connections ◽  
The Moment ◽  
Plate Connection

A series of retrofitted extended end-plate connections have been tested experimentally and evaluated using the component method specified in Eurocode 3. The component method decomposed the end-plate connection into several components, including the tension zone, compression zone, vertical and horizontal shear zone that occurred at the bolt, end-plate, beam and column. Based on the theoretical model, the moment resistance and the initial stiffness of a connection can be predicted. Four experimental tests on the retrofitted extended end-plate connections have been conducted to verify the proposed design method. From the experiment tests, all moment resistance of the connections showed good agreement with theoretical predictions, which establish a reliable foundation to predict the moment resistance of the retrofitted end-plate connection. All initial stiffnesses calculated from theoretical predictions do not represent the actual behaviour of tested connection. All tested connections can be classified as partial strength based on EC 3: Part 1.8, in condition the welding capacity is at least 50% higher than the capacity calculated from the component method.

Design Approach of Stiffeners and Model of the Initial Stiffness in Extended End-Plate Connection

2011 ◽  
Vol 243-249 ◽  
pp. 942-947 ◽  
Author(s):  
Wei Zhao ◽  
Qian Liu
Keyword(s):  
Design Method ◽  
Tensile Force ◽  
Steel Structures ◽  
Good Precision ◽  
Design Codes ◽  
Initial Stiffness ◽  
Component Method ◽  
End Plate ◽  
Extended End Plate ◽  
Plate Connection

End plate stiffener failures occure in a number of tests in recent years. And no relevant rules are given in design codes for steel structures. A design method for angles and thickness of stiffeners in extended end plate connecionts is derived by requiring the eqaul distribution of tensile force among bolts inside and outside of beam flange. And a balance between the force transmitted by the stiffener and by the beam flange is considered too. Comparisons with results of ANSYS show that the stiffeners designed by the proposed method in this paper are able to change the extended portion of endplates from one side clamped to 2 panels fixed on two adjacent sides. Simple formulas for calculating rotational rigidities of the connections with and/or without stiffeners were also proposed with component method, in which the end-plate stiffness, column flange stiffness and bolt stiffness are inclueded. Comparisons with results of ANSYS show that the proposed equations have good precision and can be applied to pratical engineering.

Analytical Study of End-Plate Connection on Cruciform Column Section

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Boon Cheik Tan ◽  
Poi Ngian Shek ◽  
Mahmood Md Tahir ◽  
Ker Shin Mu
Keyword(s):  
Analytical Study ◽  
Experimental Results ◽  
Analytical Prediction ◽  
Initial Stiffness ◽  
Component Method ◽  
End Plate ◽  
Column Section ◽  
Extended End Plate ◽  
The Moment ◽  
Plate Connection

This paper presents an analytical study on flush end-plate (FEP) and extended end-plate (EEP) connections connected to cruciform column section using component method. The objective of this study is to predict the moment resistance and initial stiffness of FEP and EEP connections on cruciform column section. A series of FEP and EEP connections are tested in laboratory. The connection tests consist of four FEP and four EEP specimens with different configuration. Component method outlined in the publication of Steel Construction Institute and British Constructional Steelwork Association are based on BS5950 and Eurocode 3 (EC3) are used to predict the moment resistance and initial stiffness of the tested specimens. The experimental results are then used to validate the analytical predictions. As compare to the experimental results, all moment resistance of the connections coincide well with analytical predictions. Analytical prediction for initial stiffness using EC3 does not show good agreement with the experimental results. This study shows that the component method can be used to predict the moment resistance of FEP and EEP connections on cruciform column section. Further study need to be carried out for initial stiffness to obtain accurate analytical representation.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

scholarly journals Analysis of multilayer electro-active tubes under different constraints

2018 ◽  
Vol 30 (1) ◽  
pp. 45-62 ◽  
Author(s):  
Eliana Bortot
Keyword(s):  
Single Layer ◽  
Layer Model ◽  
Active Materials ◽  
Practical Applications ◽  
Geometrical Properties ◽  
Active Membrane ◽  
Electromechanical Transduction ◽  
Compliant Behavior ◽  
Coating Layers ◽  
Soft Dielectrics

Dielectric elastomers are an emerging class of highly deformable electro-active materials employed for electromechanical transduction technology. For practical applications, the design of such transducers requires a model accounting for insulation of the active membrane, non-perfectly compliant behavior of the electrodes, or interaction of the transducer with a soft actuated body. To this end, a three-layer model, in which the active membrane is embedded between two soft passive layers, can be formulated. In this article, the theory of non-linear electro-elasticity for heterogeneous soft dielectrics is used to investigate the electromechanical response of multilayer electro-active tubes—formed either by the active membrane only ( single-layer tube) or by the coated active membrane ( multilayer tube). Numerical results showing the influence of the mechanical and the geometrical properties of the soft coating layers on the electromechanical response of the active membrane are presented for different constraint conditions.

Bird Metabolism During Flight: Evaluation of a Theory

1973 ◽  
Vol 58 (3) ◽  
pp. 689-709 ◽  
Author(s):  
VANCE A. TUCKER
Keyword(s):  
Reynolds Number ◽  
Absolute Error ◽  
Metabolic Rates ◽  
Avian Flight ◽  
Theoretical Predictions ◽  
Reynolds Number Effects ◽  
Plate Area ◽  
Laughing Gulls ◽  
Modified Theory ◽  
Approximate Equations

1. Pennycuick's (1969) theory for the energetic requirements of avian flight predicts the metabolic rates of budgerigars and laughing gulls flying level at intermediate speeds in a wind tunnel with an accuracy of 10% or better. However, its predictions appear to be low for most birds with masses less than 0·1 kg and high for most birds with masses greater than 0·5 kg. 2. Four modifications are made to Pennycuick's theory: (1) a different computation of induced power; (2) a different estimate of equivalent flat plate area that includes Reynolds number effects, and is based on additional measurements; (3) a different estimate of profile power that includes Reynolds number effects; and (4) the addition of power terms for respiration and circulation. These modifications improve the agreement between the theoretical predictions and existing measurements for flying birds and bats. 3. The metabolic rates of birds and bats in level flight at various speeds can be estimated by the modified theory if body mass alone is measured. Improved estimates can be made if wing span is measured as well. In the latter case the theory predicts measured values with a mean absolute error of 8·3%. 4. The results of the modified theory are presented by approximate equations that can be solved quickly for metabolic rate and flight speed with a slide rule.

scholarly journals Experimental Investigation on the Behavior of Iron Powder-Reinforced Sand under Electromagnetic Field

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Ying Lai ◽  
Bin Zhu ◽  
Xiangtian Xu
Keyword(s):  
Electromagnetic Field ◽  
Iron Powder ◽  
Soil Improvement ◽  
Triaxial Tests ◽  
Future Research ◽  
Initial Stiffness ◽  
Stress Strain ◽  
Practical Applications ◽  
Nonlinear Stress ◽  
Chang Model

Applications of soil improvement have proliferated in recent years. To date, we have limited studies on the quantitative analyses of the autoadaptive material and specifically to model its stress-strain relationship. This paper explored an autoadaptive material, iron-powdered Ottawa sand, which was temporarily solidified by applying an electromagnetic field. A series of compression triaxial tests were carried out with various relative densities of specimens (60% and 80%), in four electromagnetic fields (0 A, 0.5 A, 1 A, and 2 A) and under three confining pressures (103 kPa, 206 kPa, and 310 kPa). The test results indicate that the strength of specimens increased while initial stiffness and brittleness reduced by adding iron powder. Moreover, the strength of the specimens increased by increasing the magnitude of the applied electromagnetic field. The behavior of the iron-powdered sand was described by using a revised Duncan–Chang model. The revised model was evaluated by comparing the simulated results with the corresponding test data. The comparison showed that the revised model can better capture the nonlinear stress-strain behavior of the specimens. With the application of the revised Duncan–Chang model, the standard error of the estimate between the experimental and predicted results is lowered down to 0.39 from 4.7. Future research is geared towards practical applications for temporary solidification of soil.

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