scholarly journals BEHAVIOUR OF MINERAL WOOL SANDWICH PANELS UNDER BENDING LOAD AT ROOM AND ELEVATED TEMPERATURES

2020 ◽  
Vol 12 (1) ◽  
pp. 25-31
Author(s):  
Ashkan Shoushtarian Mofrad ◽  
Hartmut Pasternak
Keyword(s):  
Parametric Study ◽  
Elevated Temperatures ◽  
Sandwich Panels ◽  
Mineral Wool ◽  
Bending Stiffness ◽  
Experimental Results ◽  
Fe Model ◽  
Analysis And Design ◽  
Bending Load ◽  
Panel Thickness

This paper presents a parametric study for the bending stiffness of mineral wool (MW) sandwich panels subjected to a bending load. The MW panels are commonly used as wall panels for industrial buildings. They provide excellent insulation in the case of fire. In this research, the performance of sandwich panels is investigated at both ambient and elevated temperatures. To reach that goal, a finite element (FE) model is developed to verify simulations with experimental results in normal conditions and fire case. The experimental investigation in the current paper is a part of STABFI project financed by Research Fund for Coal and Steel (RFCS). The numerical study is conducted using ABAQUS software. Employing simulations for analysis and design is an alternative to costly tests. However, in order to rely on numerical results, simulations must be verified with the experimental results. In this paper, after the verification of FE results, a parametric study is conducted to observe the effects of the panel thickness, length and width, as well as the facing thickness on the bending stiffness of MW sandwich panels at normal conditions. The results indicate that the panel thickness has the most significant effect on the bending stiffness of sandwich panels.

Mechanical modeling for predicting the axial restraint forces and rotations of steel top and seat angle connections at elevated temperatures

2017 ◽  
Vol 8 (3) ◽  
pp. 258-286 ◽  
Author(s):  
Sana El Kalash ◽  
Elie Hantouche
Keyword(s):  
Mechanical Model ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Experimental Results ◽  
Fe Model ◽  
Content Type ◽  
Analysis And Design ◽  
Axial Forces ◽  
Fe Simulations ◽  
Seat Angle

Purpose This paper aims at developing a mechanical-based model for predicting the thermally induced axial forces and rotation of steel top and seat angles connections with and without web angles subjected to elevated temperatures due to fire. Finite element (FE) simulations and experimental results are used to develop the mechanical model. Design/methodology/approach The model incorporates the overall connection and column-beam rotation of key component elements, and includes nonlinear behavior of bolts and base materials at elevated temperatures and some major geometric parameters that impact the behavior of such connections when exposed to fire. This includes load ratio, beam length, angle thickness, and gap distance. The mechanical model consists of multi-linear and nonlinear springs that predict each component stiffness, strength, and rotation. Findings The capability of the FE model to predict the strength of top and seat angles under fire loading was validated against full scale tests. Moreover, failure modes, temperature at failure, maximum compressive axial force, maximum rotation, and effect of web angles were all determined in the parametric study. Finally, the proposed mechanical model was validated against experimental results available in the literature and FE simulations developed as a part of this study. Originality/value The proposed model provides important insights into fire-induced axial forces and rotations and their implications on the design of steel bolted top and seat angle connections. The originality of the proposed mechanical model is that it requires low computational effort and can be used in more advanced modelling applications for fire analysis and design.

Performance of RC T-Beams Externally Strengthened with CFRP Laminates under Elevated Temperatures

2014 ◽  
Vol 5 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Mohannad Naser ◽  
Rami Hawileh ◽  
Hayder Rasheed
Keyword(s):  
Parametric Study ◽  
Elevated Temperatures ◽  
Numerical Study ◽  
Experimental Testing ◽  
Fe Model ◽  
Cfrp Laminates ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Efficient Alternative ◽  
Fire Loading

This paper presents a numerical study that investigates the performance of reinforced concrete (RC) T-beams externally strengthened with carbon fibre reinforced polymer (CFRP) plates when subjected to fire loading. A finite element (FE) model is developed and a coupled thermal-stress analysis was performed on a RC beam externally strengthened with a CFRP plate tested by other investigators. The spread of temperature at the CFRP-concrete interface and reinforcing steel, as well as the mid-span deflection response is compared to the measured experimental data. Overall, good agreement between the measured and predicted data is observed. The validated model was then used in an extensive parametric study to further investigate the effect of several parameters on the performance of CFRP externally strengthened RC beams under elevated temperatures. The variables of the parametric study include applying different fire curves and scenarios, different applied live load combinations as well as the effect of using different insulation schemes with different types and thicknesses. Several observations and conclusions were drawn from the parametric investigation. It could be concluded that successful FE modeling of this structural member when exposed to thermal and mechanical loading would provide a valid economical and efficient alternative solution to the expensive and time consuming experimental testing.

scholarly journals Numerical Analysis of Hybrid Steel Beams with Trapezoidal Corrugated Web Nonwelded Inclined Folds

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yasir M. Alharthi ◽  
Ibrahim A. Sharaky ◽  
Ahmed S. Elamary
Keyword(s):  
Parametric Study ◽  
Fatigue Cracks ◽  
Shear Capacity ◽  
Experimental Results ◽  
Additional Stress ◽  
Steel Beams ◽  
Fe Model ◽  
Flange Thickness ◽  
Corrugated Web ◽  
Steel Grades

Hybrid beams provide the opportunity to implement characterized steel sections by recruiting materials based on yield strength and the type of applied stress. Previous studies demonstrated that steel beams with a trapezoidal corrugated web (SBCWs) were affected by both fatigue cracks initiated along the inclined fold (IF) and the maximal additional stress located in the middle of the IFs. This paper presents a numerical study of hybrid SBCWs and nonwelded IFs. Numerical simulation is presented using the finite element (FE) method with the aid of the ANSYS software package. Three-dimensional FE models were developed considering the nonlinear properties of materials and geometric imperfection and validated using five hybrid specimens that were fabricated and tested experimentally by the authors. The load-deflection behavior and failure mechanism of the numerical results were in good agreement with the experimental results. The comparison of the FE models and the experimental results shows the good capability of the FE model to be used as a base for the parametric study. The parametric study focused on the effect of web thickness, flange thickness, web height, and flange and web steel grades. Furthermore, parametric studies are conducted to investigate the effects of the number and depth of the stiffeners on the behavior of hybrid SBCWs. We concluded that the flange thickness, web thickness, web height, and steel grades of flanges significantly affect the capacity and failure mode of hybrid SBCWs. We also concluded that the flange stiffeners have a significant effect on the overall behavior, toughness, and load capacity of SBCWs. Finally, a new equation is proposed to anticipate the shear capacity of SBCW nonwelded IFs based on the length of the welded horizontal fold.

FINITE ELEMENT MODELING OF STEEL-CONCRETE COMPOSITE BEAMS STRENGTHENED WITH PRESTRESSED CFRP PLATE

2012 ◽  
Vol 12 (01) ◽  
pp. 23-51 ◽  
Author(s):  
R. EL-HACHA ◽  
P. ZANGENEH ◽  
H. Y. OMRAN
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Parametric Study ◽  
Large Scale ◽  
Composite Beams ◽  
Experimental Results ◽  
Fe Model ◽  
Element Modeling ◽  
Cfrp Plate ◽  
Good Agreement

Results from finite element modeling (FEM) of large-scale steel-concrete composite beams strengthened in flexure with prestressed carbon fiber-reinforced polymer (CFRP) plate were validated with experimental results and presented in this paper. The effect of varying the level of prestressing as percentage of the ultimate tensile strength of the CFRP plate was investigated. Comparison was carried out in terms of overall load-deflection behavior, strain profile along the length of the CFRP plate, and strain distribution across the depth of the beam at mid-span section. Very good agreement was observed between the finite element (FE) and the experimental results. The validated FE models were used to perform a comprehensive parametric study to investigate the changes in the behavior through wider range of prestressing levels and then, determine the optimum prestressing level that maintain the unstrengthened beams' original ductility (or energy absorption). An iterative analytical model was also developed, validated with both the FE model and the experimental results, and showed good agreement. A parametric study was carried out to investigate the effect of changing the yield strength of the steel and the concrete compressive strength on the moment of resistance of the section and the strain in the CFRP plate at ultimate.

Parametric study on load ratio effect on the flexural bending behaviour of axially-restrained HSS steel beams subjected to fire

2018 ◽  
Vol 9 (4) ◽  
pp. 342-360 ◽  
Author(s):  
Osama (Sam) Salem
Keyword(s):  
Fire Resistance ◽  
Parametric Study ◽  
Elevated Temperatures ◽  
Load Ratio ◽  
Steel Beams ◽  
Fe Model ◽  
Fire Behaviour ◽  
Content Type ◽  
Ratio Effect ◽  
Structural Fire

Purpose In fire condition, the limiting temperature of a restrained steel beam depends on a few parameters, e.g. temperature distributions along and across the beam, beam’s load ratio and span length. The purpose of this study is to investigate the structural fire behaviour of axially restrained steel beams under different beam’s load ratios, taking into consideration the effect of the beam’s end connections configuration. Design/methodology/approach A three-dimensional finite element (FE) computer model has been developed to simulate the structural fire behaviour of axially restrained steel beams and their end connections. After successfully validating the developed model against the outcomes of the available large-size fire resistance experiments, the FE model has been used in a parametric study to investigate the beam’s load ratio effect on the behaviour of the axially restrained steel beams and their end connections. Findings The parametric study showed that increasing the beam loading level significantly increased the beam deflections at elevated temperatures; where, increasing the beam’s load ratio from 0.5 to 0.9 reduced the beam fire resistance by about 100 s. In contrast, decreasing the beam’s load ratio from 0.5 to 0.3 allowed the beam to easily achieve a 30-min fire resistance rating with no fire protection applied. Originality/value Experimental parametric studies are difficult to control in a laboratory setting and are also expensive and time consuming. Therefore, the reasonable accuracy of the validated FE model in reproducing the experimental fire behaviour of steel beams and their end connections makes it a very useful tool for both numerical and analytical studies.

scholarly journals Stability Optimization of Trapezoidal Frame with Rigid Members and Flexible Joints

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chao Wu ◽  
Ya-Nan Li ◽  
Lik-Ho Tam ◽  
Li He
Keyword(s):  
Parametric Study ◽  
Moving Load ◽  
Closed Form Solution ◽  
Form Solution ◽  
Frame Structure ◽  
Fe Model ◽  
Flexible Joints ◽  
Analysis And Design ◽  
Portal Frame ◽  
The Stability

Stability has been an important subject in the design of a portal frame structure. Conventional stability analysis of the portal frame is normally conducted assuming that all the joints are rigid. However, the joints of a portal frame in real applications are not always rigid and semirigid connections often exist. AISC design code requires that the effect of the joint flexibility on the behavior and buckling capacity of the portal frame should be taken into account in the analysis and design procedures. To address this issue, a portal frame with flexible joints and rigid members was theoretically analyzed in the literature and closed form solution was derived for its global buckling load. However, when more parameters are involved, e.g., different leg lengths, asymmetric frame shape, and moving load, the solution to the governing equation of the stability of the frame becomes impossible. This paper presents a comprehensive parametric study on the stability of an asymmetric portal frame with flexible joints and rigid members through finite element (FE) analysis. The FE model was first validated by the existing theoretical solution in the literature. Parameters including the position of the moving load, the lengths of the two frame legs, and the span of the frame were analyzed. Design curves were developed based on the parametric study, from which the stable, unstable, and catastrophically unstable states of the portal frame were characterized. This paper contributes benchmark results for the stability optimization in the design of the portable frame of a general shape.

Finite Element Simulation of Aluminium Foam Sandwich Panels Subjected to Impact Loading

2011 ◽  
Vol 261-263 ◽  
pp. 761-764 ◽  
Author(s):  
Roger Zou ◽  
Dong Ruan ◽  
Guo Xing Lu
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Sandwich Panels ◽  
Aluminium Foam ◽  
Experimental Results ◽  
Skin Thickness ◽  
Fe Model ◽  
Element Simulation ◽  
Core Thickness ◽  
Commercial Software Package

One potential application of aluminium foam sandwich panels in civil engineering is the cladding system which is employed to protect other structures again impact and blast loadings. Finite element (FE) simulation of these sandwich panels subjected to impact loading was conducted by using a commercial software package, LS-DYNA (version 971). The FE model was verified by experimental results conducted previously. Good agreement was achieved between the FE and experimental results. Parametric study was conducted to investigate the effects of skin thickness, core thickness and boundary conditions on the deformation modes and energy absorption of sandwich panels with aluminum foam core.

scholarly journals Evaluating bending stiffness and resistance of sandwich panels at elevated temperatures

2019 ◽  
Author(s):  
Ashkan Shoushtarian Mofrad ◽  
Darita Shlychkova ◽  
Yvonne Ciupack ◽  
Hartmut Pasternak
Keyword(s):  
Normal Condition ◽  
Elevated Temperatures ◽  
Thermal Analyses ◽  
Sandwich Panels ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Core Material ◽  
Steel Buildings ◽  
In Fire ◽  
Future Work

The objective of this research is to develop a modeling and simulation approach for the bending stiffness of sandwich panels which have been verified and compared by experimental results in normal condition and fire case. For this purpose, polyisocyanurate (PIR) foam has been used as core material along with trapezoidal sheeting. In order to simulate the experiments, Finite Element (FE) software ABAQUS has been applied. The modelling process contains heat transfer analyses, mechanical analyses in normal condition and sequential analyses which includes the combination of both mechanical analyses and thermal analyses. The main aim of this paper is to investigate the effect of fire on the bending stiffness and stabilization of sandwich panels. Although with increase in temperature the strength of panels decreases, this decline is not linear. The presented work should be considered as first step in STABFI project financed by Research Fund for Coal and Steel (RFCS) which its purpose is to investigate translational and also torsional stiffness of sandwich panels as future work. STABFI stands for steel cladding systems for stabilization of steel buildings in fire.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals Analysis of the transmission loss of double-leaf panels with an equivalent spring–mass model for studs

2020 ◽  
Vol 37 ◽  
pp. 126-133
Author(s):  
Yuan-Wei Li ◽  
Chao-Nan Wang
Keyword(s):  
Distribution Curve ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Experimental Results ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Mass Model ◽  
Steel Stud ◽  
Panel Thickness ◽  
Stiffness Distribution

Abstract The purpose of this study was to investigate the sound insulation of double-leaf panels. In practice, double-leaf panels require a stud between two surface panels. To simplify the analysis, a stud was modeled as a spring and mass. Studies have indicated that the stiffness of the equivalent spring is not a constant and varies with the frequency of sound. Therefore, a frequency-dependent stiffness curve was used to model the effect of the stud to analyze the sound insulation of a double-leaf panel. First, the sound transmission loss of a panel reported by Halliwell was used to fit the results of this study to determine the stiffness of the distribution curve. With this stiffness distribution of steel stud, some previous proposed panels are also analyzed and are compared to the experimental results in the literature. The agreement is good. Finally, the effects of parameters, such as the thickness and density of the panel, thickness of the stud and spacing of the stud, on the sound insulation of double-leaf panels were analyzed.

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