scholarly journals Experimental and Numerical Investigations of Ultimate Strength of Imperfect Stiffened Plates of Different Slenderness

2020 ◽  
Vol 27 (4) ◽  
pp. 120-129
Author(s):  
Krzysztof Woloszyk ◽  
Yordan Garbatov ◽  
Jakub Kowalski ◽  
Leszek Samson
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Compressive Force ◽  
Initial Imperfection ◽  
Element Model ◽  
Stiffened Plates ◽  
Structural Behaviour ◽  
Middle Cross Section ◽  
Geometrical Imperfections

AbstractThe objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive force, and the most important quantities related to the structural behaviour were captured and analysed. A finite element model, accounting for material and geometrical nonlinearities and initial geometrical imperfections, was developed using the commercial software ANSYS. The residual welding-induced stresses were measured in the middle cross-section for two specimens. The initial imperfection was identified by employing a close-range photogrammetry approach. It was concluded that the numerical analyses, based on the finite element model, predict the ultimate strength of stiffened plates accurately, although some deviations were also observed. The detailed analysis with the indication of possible uncertainty is presented, and several conclusions are derived.

Behaviour of cold-formed steel built-up I-section columns composed of four U-profiles

2018 ◽  
Vol 22 (3) ◽  
pp. 613-625 ◽  
Author(s):  
M Anbarasu ◽  
M Venkatesan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Element Model ◽  
Cross Sectional ◽  
Direct Strength Method ◽  
The North ◽  
Compression Members ◽  
Cross Sectional Dimension ◽  
Cold Formed Steel

This work reports numerical results concerning the cold-formed steel built-up I-section columns composed of four U-profiles under axial compression. A finite element model is developed by using the software program ABAQUS. The developed model includes geometric, material nonlinearities and geometric imperfections. The finite element model was verified against the experimental results reported in the cold-formed steel built-up open section columns. In the parametric study, the sections are analysed with several cross-sectional dimension ratios and lengths, in order to assess their influence on the buckling behaviour and ultimate strength of cold-formed steel built-up I-section columns. After presenting and discussing the numerical parametric results, the article shows that the current direct strength method in the North American Specification for cold-formed steel compression members design curve fails to predict adequately the ultimate strength of some of the columns analysed and addresses the modification proposed on current direct strength method curves, providing improved predictions of all the numerical ultimate strength available. The proposed method is also assessed by reliability analysis.

PHOTOGRAMMETRY MEASUREMENTS OF INITIAL IMPERFECTIONS FOR THE ULTIMATE STRENGTH ASSESSMENT OF PLATES

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
A Cubells ◽  
Y Garbatov ◽  
C Guedes Soares
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Compressive Load ◽  
Initial Imperfection ◽  
Maximum Load ◽  
Surface Shape ◽  
Element Analysis ◽  
Strength Assessment ◽  
Load Carrying ◽  
Geometrical Imperfections

The objective of the present study is to develop a new approach to model the initial geometrical imperfections of ship plates by using Photogrammetry. Based on images, Photogrammetry is able to take measurements of the distortions of plates and to catch the dominant surface shape, including the deformations of the edges. Having this data, it is possible to generate faithful models of plate surface based on third order polynomial functions. Finally, the maximum load- carrying capacity of the plates is analysed by performing a nonlinear finite element analysis using a commercial finite element code. Three un-stiffened and four stiffened plates have been modelled and analysed. For each plate, two initial imperfection models have been generated one, based on photogrammetric measurements and the other, based on the trigonometric Fourier functions. Both models are subjected to the same uniaxial compressive load and boundary conditions in order to study the ultimate strength.

Ultimate strength of columns laterally braced by girt–diaphragm systems

1989 ◽  
Vol 16 (3) ◽  
pp. 227-238 ◽  
Author(s):  
Bruno Massicotte ◽  
Denis Beaulieu ◽  
André Picard
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Design Method ◽  
Element Model ◽  
Structural System ◽  
Industrial Buildings ◽  
Stabilizing Effect ◽  
Stability Statistics

This paper deals with the stabilizing effect of girts and cladding on columns in light industrial buildings. The construction aspects of such systems are briefly reviewed and a description of their behavior is presented. Solutions available to determine column strength in column–girt–diaphragm systems are reviewed. The use of a finite-element-based software is proposed as the only practical way to analyze this type of structural system. Results of a large parametric study using a finite element model are presented and a method to evaluate the ultimate strength of actual columns is introduced. Finally, a simple hand design method is derived. Key words: diaphragm, design, finite element, girt, column, stability, statistics.

Strength Analyses of Sandwich Pipes for Ultra Deepwaters

2004 ◽  
Vol 72 (4) ◽  
pp. 599-608 ◽  
Author(s):  
Segen Farid Estefen ◽  
Theodoro Antoun Netto ◽  
Ilson Paranhos Pasqualino
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Thermal Insulation ◽  
Research Work ◽  
Element Model ◽  
Material Behavior ◽  
Core Material ◽  
Small Scale ◽  
Mechanical Resistance

Design requirements for pipelines regarding both ultimate strength and flow assurance in ultra deepwater scenarios motivated the development of a new sandwich pipe which is able to combine high structural and thermal insulation properties. In this concept, the annulus is filled with low cost materials with adequate thermal insulation properties and good mechanical resistance. The aim of this research work is to perform small-scale laboratorial tests and to develop a finite element model to evaluate the structural performance of such sandwich pipes with two different options of core material. After calibrated in view of the experimental results, a three-dimensional finite element model incorporating nonlinear geometric and material behavior is employed to perform strength analyses of sandwich pipes under combined external pressure and longitudinal bending. Ultimate strength envelopes for sandwich pipes are compared with those generated for single-wall steel pipes with equivalent collapse pressures. The study shows that sandwich pipe systems with either cement or polypropylene cores are feasible options for ultra deepwater applications.

Ultimate Strength Assessment of Semi-Submersible Platform Under Different Load Conditions

2017 ◽  
Author(s):  
Yangzhe Yu ◽  
Guoqing Feng ◽  
Huilong Ren
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
High Stress ◽  
Initial Imperfection ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Main Bearing ◽  
Strength Assessment ◽  
Hull Structure ◽  
Load Conditions

The nonlinear finite-element method has been widely used in evaluating the ultimate strength of stiffened plates and part of hull girders, considering the effect of boundary conditions, geometrical initial imperfection and welding-induced residual stress in recent years. However, available research on the ultimate strength of large-sized structures, especially of semi-submersible platform is limited. New large-sized semi-submersible platform has been designed with lateral brace structure and square cross-section columns. The investigation of ultimate strength of the whole structure is of paramount importance in assessing the safety and design of such large structure. Therefore, in this paper, a three-dimensional nonlinear finite element model was developed to investigate the ultimate strength of a new generation of semi-submersible platform under different load conditions and its behavior after collapse using explicit dynamic solvers. Results showed that the time dependent dynamic explicit method was reliable and feasible for the calculation of ultimate strength of such complicated structure. For the target platform, the bracings and upper hull structure were the main bearing component and were critical for the ultimate strength of the whole structure. High stress occurred in connection areas and special attention shall be paid for.

scholarly journals Assessment of the dynamic structural behaviour of footbridges based on experimental monitoring and numerical analysis

2020 ◽  
Vol 13 (3) ◽  
pp. 563-577
Author(s):  
G. L. DEBONA ◽  
J. G. S. da SILVA
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Rio De Janeiro ◽  
Research Work ◽  
Experimental Tests ◽  
Element Model ◽  
Modal Testing ◽  
Structural Behaviour ◽  
Human Comfort ◽  
Vibration Tests

Abstract This research work aims to investigate the dynamic structural behaviour and assess the human comfort of footbridges, when subjected to pedestrian walking, based on experimental tests and tuning of finite element model. Therefore, the investigated structure is associated to a real pedestrian footbridge, spanning 24.4m, located at the campus of the State University of Rio de Janeiro (UERJ), Rio de Janeiro, Brazil. Initially, an experimental modal testing was conducted using two data acquisition strategies. After that the experimental forced vibration tests were performed on the footbridge, considering the pedestrians walking with different step frequencies. In sequence of the study, a finite element model was developed based on the ANSYS computational program. The experimental footbridge tests were used for the calibration of results on the numerical model. Finally, a human comfort assessment was performed, based on the comparisons between the results (peak accelerations), of the dynamic experimental monitoring and the recommendations provided by design guides SÉTRA, HIVOSS and AISC.

Modeling of Steel-Reinforced Concrete Panels under Blast Loads

2014 ◽  
Vol 553 ◽  
pp. 100-105
Author(s):  
Xiao Shan Lin ◽  
Yi Xia Zhang ◽  
Paul Jonathan Hazell
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Strain Rate ◽  
Blast Loading ◽  
Element Model ◽  
Strain Rate Effect ◽  
Structural Behaviour ◽  
Steel Reinforced Concrete ◽  
Concrete Panels

In this study, a finite element model is developed for simulation of the structural behaviour of steel-reinforced concrete panels under blast loading using LS-DYNA. Pure Lagrangian formulation is applied in the finite element analysis, and the strain rate effect is taken into account in the material models of both concrete and steel. The finite element model is validated by comparing the computed results with experimental test results from the literature. Structural behaviour of concrete panel with different parameters under blast loading is also investigated. Keywords: Blast resistance; Finite element model; Reinforced concrete panel; Strain rate effect

Analysis and Results of an SCS-6/Ti-15-3 MMC Reinforced Ring Structure Under Internal Radial Loading

1993 ◽  
Author(s):  
Phillip W. Gravett ◽  
Robert E. deLaneuville
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Ultimate Strength ◽  
Element Model ◽  
Ring Structure ◽  
The State ◽  
Stress Concentrations ◽  
State Of Stress

Abstract This paper presents a stress analysis method and test results of a ring structure reinforced with SCS-6/Ti-15-3 MMC under an applied internal radial load. To assess the structural integrity of an MMC reinforced component, the state of stress within the component must be determined. Two major factors complicating the state of stress in the given MMC reinforced rings are the stress concentrations caused by the load fixture and the thermal residual stresses induced during processing. To model the stress concentrations, the ring and its load fixture were modeled as a 3-d solid finite element model. To calculate the processing residual stresses, a 2-d axisymetric finite element thermal stress analysis was completed. Plasticity was modeled with the 2-d axisymetric finite element model accounting for the nonlinear response of the MMC core and monolithic sheath. Testing of the rings at room and high temperature showed good correlation to load-deflection calculations while ultimate strength was far less than predicted. Subsequent post failure analysis revealed preexisting damage within the MMC which was not detected by pretest NDE inspections. This damage did not significantly affect the measured stiffness of the ring, but diminished the ultimate strength by reducing the capability of the MMC in a localized area.

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