scholarly journals Experimental and Numerical Study of Mild Steel Behaviour under Cyclic Loading with Variable Strain Ranges

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Paulina Krolo ◽  
Davor Grandić ◽  
Željko Smolčić
Keyword(s):  
Cyclic Loading ◽  
Numerical Study ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Hardening Model ◽  
High Deformation ◽  
Cyclic Behaviour ◽  
Time Calibration ◽  
Steel Grades ◽  
Steel Hardening

To simulate the effect of variable strains on steel grades S275 and S355, an experimental displacement control test of plate specimens was performed. Specimens were tested under monotonic and cyclic loading according to the standard loading protocol of SAC 2000. During experimental testing, strain values were measured with an extensometer at the tapered part of the specimen. Strains obtained by the experimental tests are disproportional to the applied displacements at the ends of the specimens. This phenomenon occurs due to the imperfections of the specimen, hardening of the material, and the buckling behaviour that appears in real structures due to the high deformation experienced during earthquakes. Due to the relative simplicity and wide applicability of the Chaboche hardening model of steel, the calibration of hardening parameters based on experimental test results was conducted. For the first time, calibration of steel hardening parameters was performed following the Chaboche procedure to define the cyclic behaviour with variable strain ranges. The accuracy of the hardening model with variable strain ranges, which were simulated using ABAQUS software, was verified using the experimental results.

scholarly journals Development of Impact-Echo Multitransducer Device for Automated Concrete Homogeneity Assessment

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2144
Author(s):  
Bartłomiej Sawicki ◽  
Tomasz Piotrowski ◽  
Andrzej Garbacz
Keyword(s):  
Nondestructive Testing ◽  
Numerical Study ◽  
Numerical Models ◽  
Experimental Testing ◽  
Experimental Tests ◽  
Impact Echo ◽  
University Of Technology ◽  
Homogeneity Assessment

A combination of multiple nondestructive testing (NDT) methods speeds up the assessment of concrete and increases the precision. This is why the UIR-Scanner was developed at Warsaw University of Technology. The scanner uses an Impact-Echo (IE) method with a unique arrangement of multiple transducers. This paper presents the development of the IE module using numerical models validated with experimental testing. It was found that rectangular arrangement of four transducers with the impactor in the middle is optimal for quick scanning of area for faults and discontinuities, changing the method from punctual to volumetric. A numerical study of void detectability depending on its position with respect to the IE module is discussed as well. After confirmation of the findings of models using experimental tests, the module was implemented into the scanner.

scholarly journals Viscoplastic Parametric Analysis of Cylindrical Specimen Under Cyclic Behaviour

2021 ◽  
pp. 75-82
Author(s):  
Panagiotis J. Charitidis
Keyword(s):  
Cyclic Loading ◽  
Numerical Study ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Material Model ◽  
Cyclic Plasticity ◽  
Axial Deformation ◽  
Cyclic Behaviour ◽  
Von Mises ◽  
Cyclic Plasticity Model

The present study tries to present a cyclic hardening model with the aim to simulate quantitatively the material response under strain controlled cyclic loading in tension-compression, of specified axial deformation. A numerical study was carried out to investigate the cyclic constitutive behaviour of alloy Indium under viscoplastic deformation. The analysis was performed under prescribed symmetric strain-controlled cyclic loading. The model contains both isotropic and kinematic hardening components, while the analysis were performed using Comsol Multiphysics for only 60 seconds duration. The kinematic hardening was described by using multiple back stresses. Multiple back stresses can provide a smoother transition between the elastic and plastic deformation, and it improves the general shape of the hysteresis loop. Two cases (geometries) have been examined in this study. From the material model and finite element cyclic plasticity model results, it is found that for the same parameters, but different dimensions there is difference on the stress-strain curves as well as on the von Mises stresses.

scholarly journals Combined hardening parameters of steel CK45 under cyclic strain-controlled loading: Calibration methodology and numerical validation

2020 ◽  
Vol 14 (2) ◽  
pp. 6848-6855
Author(s):  
Bahman Paygozar ◽  
S.A Dizaji ◽  
M.A Saeimi Sadigh
Keyword(s):  
Cyclic Loading ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Strain Curve ◽  
Experimental Tests ◽  
Isotropic Hardening ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Hardening Model ◽  
Combined Hardening

This study is to indicate the methodology of investigating the behavior of materials in the plastic domain while bearing cyclic loading i.e. low cycle fatigue. Materials under such loading, which experience huge amount of plastic deformation, are affected by the hardening or softening effects of loading which should be taken into account in all applications and numerical simulations as well. This work investigates the methodology of obtaining the nonlinear isotropic and kinematic hardening of steel CK45. To find the parameters of the above mentioned combined nonlinear isotropic/kinematic hardening one tensile test as well as three strain-controlled low cycle fatigue tests are carried out to extract the monotonic stress/strain curve and three diagrams of hysteresis curves, respectively. Then, four parameters necessary to simulate the nonlinear isotropic/ kinematic behavior of the material are extracted by means of curve fitting technique using MATLAB software. Afterwards, the accuracy of the data extracted from the experimental tests using the proposed methodology, are verified in a finite element package, ABAQUS, through implementing two user defined subroutines UMAT written in FORTRAN. It is indicated that the computed constants draw stress-strain curves much closer to experimental responses than isotropic hardening model does.  Eventually, the numerical results acquired by simulating the behavior of the sample under cyclic loading with importing the constants, calculated via combined hardening model, to ABAQUS reflects results highly close to the experimentally obtained response of the sample. It means that the procedure used to find the constants is accurate enough and consequently the constants computed are able to be used in both ABAQUS and subroutines.     

On-Site Experimental Testing to Study the Vibration of Composite Floors

2014 ◽  
Vol 601 ◽  
pp. 231-234
Author(s):  
Cristian Lucian Ghindea ◽  
Dan Cretu ◽  
Monica Popescu ◽  
Radu Cruciat ◽  
Elena Tulei
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Testing ◽  
Concrete Slab ◽  
Human Perception ◽  
Experimental Tests ◽  
International Standards ◽  
Structural Element ◽  
Element Analysis ◽  
Floor Slabs ◽  
Composite Floors

As a general trend, in order to reduce material consumption or to reduce the mass of the structures, composite floor slabs solutions are used to achieve large spans floor slabs. This solutions led to floors sensitive to vibrations induced generally by human activities. As a verification of the design concepts of the composite floors, usually, it is recommended a further examination of the floor after completion by experimental tests. Although the experimental values of the dynamic response of the floor are uniquely determined, the processing can take two directions of evaluation. The first direction consist in determining the dynamic characteristics of the floor and their comparison with the design values. Another way that can be followed in the processing of the experimental results is to consider the human perception and comfort to the vibration on floors. The paper aims to present a case study on a composite floor, with steel beams and concrete slab, tested on-site. Both aspects of data processing are analyzed, in terms of the structural element, and in terms of the effect on human perception and comfort. Experimentally obtained values for the dynamic characteristics of the floor are compared with numerical values from finite element analysis, while the second type of characteristic values are compared with various human comfort threshold values found in international standards.

Experimental and numerical study of square HSS BIEs under cyclic loading

2022 ◽  
Vol 252 ◽  
pp. 113669
Author(s):  
Andrés González Ureña ◽  
Robert Tremblay ◽  
Colin A. Rogers
Keyword(s):  
Cyclic Loading ◽  
Numerical Study

Numerical Investigation of Ductile Fracture in Pipelines Under Complex Loading Using a Phenomenological Damage Model

2021 ◽  
Author(s):  
Iago S. Santos ◽  
Diego F. B. Sarzosa
Keyword(s):  
Ductile Fracture ◽  
Mechanical Response ◽  
Numerical Study ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Numerical Procedure ◽  
Complex Loading ◽  
Experimental Tests ◽  
Compact Tension ◽  
Axial Tensile

Abstract This paper presents a numerical study on pipes ductile fracture mechanical response using a phenomenological computational damage model. The damage is controlled by an initiation criterion dependent on the stress triaxiality and the Lode angle parameter, and a post-initiation damage law to eliminate each finite element from the mesh. Experimental tests were carried out to calibrate the elastoplastic response, damage parameters and validate the FEM models. The tested geometries were round bars having smooth and notched cross-section, flat notched specimens under axial tensile loads, and fracture toughness tests in deeply cracked bending specimens SE(B) and compact tension samples C(T). The calibrated numerical procedure was applied to execute a parametric study in pipes with circumferential surface cracks subjected to tensile and internal pressure loads simultaneously. The effects of the variation of geometric parameters and the load applications on the pipes strain capacity were investigated. The influence of longitudinal misalignment between adjacent pipes was also investigated.

Performance of parking steel column damaged by fire

2019 ◽  
Vol 10 (2) ◽  
pp. 138-154
Author(s):  
Farshid Masoumi ◽  
Ebrahim Farajpourbonab
Keyword(s):  
Cyclic Loading ◽  
Seismic Performance ◽  
Numerical Study ◽  
Mechanical Analysis ◽  
Content Type ◽  
Steel Columns ◽  
Fire Engineering ◽  
Steel Column ◽  
Concrete Coating ◽  
Fire Loading

Purpose The primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading. Design/methodology/approach In this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions. Findings The result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states. Originality/value This study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.

scholarly journals BEHAVIOR OF HYBRID STEEL/GFRP REINFORCED COLUMNS UNDER LATERAL CYCLIC LOADING: A NUMERICAL STUDY

2021 ◽  
Vol 1 (1) ◽  
pp. 110-121
Author(s):  
Ahmed Arafa ◽  
Ata Shoeib ◽  
Sara Dandrawy
Keyword(s):  
Cyclic Loading ◽  
Numerical Study
Sign in / Sign up

Export Citation Format

Share Document