scholarly journals Effect of radiation inside square hollow section under moderate non-symmetric fire

Fire Research ◽  
2018 ◽  
Author(s):  
Jolanta Bączkiewicz ◽  
Sami Pajunen ◽  
Markku Heinisuo
Keyword(s):  
Elevated Temperatures ◽  
Standard Procedure ◽  
Surface Heat ◽  
Heat Radiation ◽  
Gas Temperature ◽  
Hollow Section ◽  
Temperature Calculation ◽  
Steel Sections ◽  
Method Analysis ◽  
Steel Section

The temperature calculation of hollow steel sections at elevated temperatures is a well-documented and standard procedure. Through this standard procedure, the temperature can be calculated by assuming a uniform gas temperature all around the section, which is called a symmetric fire in this paper. Embedding in surrounding structures or connecting to another steel member results in non-symmetric heat distribution in the member. This non-symmetricity of the surrounding temperature may cause surface- to-surface heat radiation inside the member, thus affecting the steel section temperature distribution. This effect is considered in this paper by adopting analytical and finite element method analysis.

scholarly journals A detailed investigation on thermal behaviour of slim floor beams with web openings at elevated temperatures

2019 ◽  
Vol 10 (4) ◽  
pp. 446-467
Author(s):  
Naveed Alam ◽  
Ali Nadjai ◽  
Olivier Vassart ◽  
Francois Hanus
Keyword(s):  
Finite Element ◽  
Thermal Behaviour ◽  
Elevated Temperatures ◽  
Major Influence ◽  
Web Openings ◽  
Content Type ◽  
Composite Action ◽  
Temperature Development ◽  
In Fire ◽  
Steel Section

Purpose In recent times, the use of steel sections with web openings has become common as slim floor beams because they offer a reduction in weight of the steelwork, accommodate services within the floor depth and provide the composite action. The composite action in these beams is achieved either through the concrete dowels or through concrete plugs. Though these web openings offer several benefits in slim floor beams, they induce the material discontinuity in the steel web, which may affect their shear capacity and/or thermal behaviour. The purpose of this study is to investigate the thermal behaviour of slim floor beams with web openings in fire. Design/methodology/approach This research presents findings from experimental and analytical investigations conducted to study the thermal behaviour of slim floor beams with web openings in fire. For this purpose, an experimental investigation was conducted, which shows that the presence of web openings has a major influence on temperature development across the steel section as well as along the span of these beams. The behaviour of the tested slim floor beam is validated using finite element modelling. The validated finite element model is then used to conduct a sensitivity study to analyse the influence of different opening spacings, sizes and shapes on the thermal performance of slim floor beams in fire. Findings Test results show that the presence of web openings has a major influence on temperature development across the steel section as well as along the span of these beams. Temperatures on the web below the openings are found to be higher as compared to those recorded on the adjacent solid steel web. It is also observed that temperatures on the steel web above the openings are lesser than those on the adjacent solid steel web. Parametric studies conducted using the verified analytical modelling methods show that different opening spacings, sizes and shapes have a variable impact on the thermal behaviour of slim floor beams in fire. Closely spaced and larger opening sizes were found to have a more severe influence on their thermal behaviour in fire as compared to widely spaced and smaller openings. It was also found that the behaviour of these beams is influenced by the shape of the openings with rectangular openings resulting in more severe thermal distributions as compared to circular openings. Originality/value The findings from this research study are highly valuable as they contribute to the existing knowledge database. There is a lack of experimental and analytical investigation on performance of slim floor beams with web openings at elevated temperatures. The results and conclusions from this study will help in developing innovative designs for slim floor beams and will help in reducing the fire related risk associated with structures comprising of slim floor beams with web openings.

Experimental Study on Lateral -Torsional Buckling of Triangular Web Profile Steel Section

2015 ◽  
Vol 802 ◽  
pp. 178-183 ◽  
Author(s):  
Hazwani Hasan ◽  
Fatimah De’nan ◽  
Kok Keong Choong
Keyword(s):  
Bending Test ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Four Point Bending ◽  
Percentage Difference ◽  
Design Values ◽  
Triangular Profile ◽  
Steel Sections ◽  
Manual Calculation ◽  
Steel Section

Triangular web profile (TriWP) is a structural steel section made of two flanges connected to a web plate of triangular profile. The ability of TriWP to resist lateral–torsional buckling (LTB) is one of the most important criteria considered in the design of this steel section. This study examined the LTB behavior of TriWP steel section and determined the buckling moment resistance (Mb,Rd) for TriWP. Beam specimens were analyzed using a four-point bending test. Four types of specimen sizes were used: 200 mm × 100 mm × 6.3 mm × 6 mm; 200 mm × 100 mm × 9 mm × 6.3 mm; 200 mm × 100 mm × 8 mm × 6 mm; and 200 mm × 100 mm × 6 mm × 5 mm sections. Testing results for all specimen sizes showed that the values for Mb,Rdof the TriWP steel sections were higher than those of the flat web section. The percentage difference of Mb,Rdfrom the experimental results for all specimen sizes ranged from 10.38% to 17.37%. The percentage difference of Mb,Rdof the experimental and design values based on manual calculation by using Eurocode 3 ranged from 9.13% to 43.8%.

The Effects of Engine Degradation on Creep - Using a Transient Engine Simulation

1996 ◽  
Author(s):  
P. Darrin Little ◽  
Riti Singh
Keyword(s):  
Elevated Temperatures ◽  
Weight Ratio ◽  
Operating Costs ◽  
Gas Temperature ◽  
Military Aircraft ◽  
Significant Development ◽  
Engine Simulation ◽  
Hot Gas ◽  
Improved Performance ◽  
Free Body

The aero-gas turbine has undergone significant development to improve the thrust to weight ratio. These developments have increased the engine’s capability to withstand elevated temperatures which corresponds to both improved performance and increases in hot section creep. In addition, as the engine’s condition degrades over time, the gas generator’s rotational speed, free body stresses, and the hot gas temperature are further increased. To maximize the potential safe life of an engine and reduce operating costs, understanding the effects of engine component degradations on component life is essential. This paper examines the effects of engine degradation on the failure mechanism of creep, and presents a method in which the metal temperatures can be tied to transient parameters. The use of transient parameters enables engine stresses and temperatures to be determined at any operating point, which is essential for military aircraft engines.

scholarly journals Model of Complex Heat Transfer in the Package of Rectangular Steel Sections

2020 ◽  
Vol 10 (24) ◽  
pp. 9044
Author(s):  
Rafał Wyczółkowski ◽  
Marek Gała ◽  
Vazgen Bagdasaryan
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Thermal Resistance ◽  
Heat Radiation ◽  
Low Carbon ◽  
Contact Heat ◽  
Total Thermal Resistance ◽  
Model Calculations ◽  
Complex Heat Transfer ◽  
Steel Sections

During heat treatment of rectangular steel sections, a heated charge in the form of regularly arranged packages is placed in a furnace. The article presents a model of a complex heat transfer in such a package using the thermo-electric analogy. The model considers the following types of heat transfer: conduction in section walls, conduction and natural convection within gas, heat radiation between the walls of a section, as well as contact conduction between the adjacent sections. The results of our own experimental research were used for calculations of heat resistance applying to natural convection and contact conduction. We assumed that the material of sections was low-carbon steel and the gas was air. The result of the calculations of the presented model is total thermal resistance Rto. The calculations were performed for the temperature range 20–700 °C for four geometrical cases. Due to the variability of conditions for contact heat conduction, we assumed that total thermal resistance for a given charge is contained within a value range between Rto-min and Rto-max. We established that the value of Rto depends significantly on the section’s geometry. The larger the section sizes, the greater the changes of Rto. The minimal and maximal values of Rto for all packages were 0.0051 (m2·K)/W and 0.0238 (m2·K)/W, respectively. The correctness of model calculations was verified with the use of experimental data.

Radiative Transfer in Hartmann MHD Flow

1979 ◽  
Vol 101 (3) ◽  
pp. 502-506 ◽  
Author(s):  
T. F. Smith ◽  
P. H. Paul
Keyword(s):  
Radiative Transfer ◽  
Mhd Flow ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Radiative Properties ◽  
Temperature Profiles ◽  
Gas Temperature ◽  
Real Gas ◽  
Gaseous Products ◽  
Transfer Term

The high temperatures and gaseous products resulting from combustion of hydrocarbon fuels in magnetohydrodynamic generators have provided an impetus to develop more accurate methods for prediction of gas temperature profiles and heat fluxes at the generator walls. One area where an improvement may be realized is in the evaluation of radiative transfer between the gas and surrounding walls. Analyses and results are presented to examine the importance of the radiative transfer term appearing in the gas energy balance for classical Hartmann MHD flow. Results for both real (nongray) and gray gas radiative properties are presented. Inclusion of radiation is found to increase the surface heat flux as well as to alter gas temperature profiles. Furthermore, real gas results differ significantly from those for a gray gas.

DISTORTIONAL BUCKLING OF COLD-FORMED STEEL SECTIONS SUBJECTED TO UNIFORMLY DISTRIBUTED TRANSVERSE LOADING

2010 ◽  
Vol 10 (05) ◽  
pp. 1017-1030 ◽  
Author(s):  
JIAN-KANG CHEN ◽  
LONG-YUAN LI
Keyword(s):  
Critical Stress ◽  
Stress Gradient ◽  
Transverse Loading ◽  
Distortional Buckling ◽  
Numerical Examples ◽  
Steel Sections ◽  
Cold Formed Steel ◽  
Steel Section

This paper presents an investigation on the influence of stress gradient on the elastic critical stress of distortional buckling of cold-formed steel sections supporting wall sheeting or roof cladding in buildings. The critical stress of distortional buckling of cold-formed steel section beams subjected to a uniformly distributed transverse loading is calculated using the model proposed recently by Li and Chen. The sections investigated in the paper include channel, zed, and sigma sections. Numerical examples are provided that highlight the influence of stress gradient, section dimensions, and sheeting lateral restraints on the critical stress of distortional buckling.

scholarly journals Shear connection requirements for composite cellular beams

2018 ◽  
Author(s):  
Eleftherios Aggelopoulos ◽  
Francois Hanus ◽  
Mark Lawson
Keyword(s):  
Finite Element ◽  
Minimum Degree ◽  
Composite Beams ◽  
Beam Test ◽  
Current Version ◽  
Web Openings ◽  
Shear Connection ◽  
Low Degree ◽  
Steel Sections ◽  
Steel Section

Beams with regular circular web openings (cellular beams) are often used in composite construction. Rules for the minimum degree of shear connection in composite beams are presented in Eurocode 4 but were derived for solid web beams in propped construction. This paper investigates the degree of shear connection requirements for composite cellular beams, focusing on the combined effect of using a steel section with regularly spaced, large circular web openings and unpropped construction conditions. The effect of the diameter and the spacing of the openings is also investigated. In order to provide rules for the minimum degree of shear connection in cellular beams, parametric finite element (FE) analyses were carried out for beams in the span range of 9 to 18 m. The results were calibrated against a 15.3 m span composite cellular beam test with a low degree of shear connection. The proposed minimum degree of shear connection requirements for beams with regular circular web openings are presented for both propped and unpropped construction, and for symmetric and asymmetric steel sections. Comparisons are made with equivalent beams with solid webs (no openings) and it is shown that significant relaxation in the codified minimum degree of shear connection to the current version of Eurocode 4 can be justified for composite cellular beams.  

Study on Bending Behaviour of Triangular Web Profile Steel Section by Finite Element Analysis

2011 ◽  
Vol 94-96 ◽  
pp. 1539-1544 ◽  
Author(s):  
Fatimah De’nan ◽  
Nor Salwani Hashim
Keyword(s):  
Finite Element ◽  
Shell Element ◽  
Finite Element Models ◽  
Element Analysis ◽  
Bending Performance ◽  
Finite Element Software ◽  
Triangular Profile ◽  
Steel Sections ◽  
Element Type ◽  
Steel Section

A triangular web profile (TRIWP) steel section is a built-up section made up of two flanges connected to a web plate of triangular profile. This paper describes the study on the bending performance in major (Ix) and minor (Iy) axes of Triangular Web Profile (TRIWP) compared to flat web (FW) steel sections. A number of finite element models were developed using finite element software LUSAS version 14.3. Thin shell element which is a family of shell element in 3D dimension was chosen to represent the element type of the model. Two sizes of FW as control specimens and two sizes of TRIWP steel section which is 200×100×6×3 mm and 180×75×5×2 mm were used. Each of steel section was modeled using several spans such as 3m, 4m and 4.8m. The finite element results show that the deflections in major axes for TRIWP more than FW steel section. It was noted that, the value of Ix for the TRIWP is 0.754 to 1.523 times the Ix of FW steel section. On the other hand, the deflections in minor axes for TRIWP lower than FW steel section. The value of Iy for the TRIWP is 1.818 to 1.686 times the Iy of FW steel section. It can be concluded that the TRIWP is stiffer compared to FW steel section in minor axes and TRIWP has a higher resistance to bending in minor axes than FW steel section.

Composite concrete beam with multi-web cold-formed steel section

2019 ◽  
Vol 10 (2) ◽  
pp. 20
Author(s):  
Ahmed Youssef Kamal ◽  
Nader Nabih Khalil
Keyword(s):  
Experimental Test ◽  
Load Capacity ◽  
Reference Beam ◽  
Experimental Results ◽  
Structural Behaviour ◽  
Test Program ◽  
Concentrated Load ◽  
Steel Sections ◽  
Cold Formed Steel ◽  
Steel Section

Lately, structural engineers use cold-formed steel sections (CFS) in buildings due to its light-weight and easy shaping. Encasing the cold-formed steel sections by concrete avoiding the structure elements some of its disadvantages especially buckling. This paper reports an experimental test program for beams with a multi-web cold-formed steel section encased by reinforced concrete. Eleven (full-scale) specimens have tested under mid-span concentrated load, the experimental test program designed to cover many cold-formed steel section variables such as (web number, web height, and the steel section length). Comparison between the experimental results for specimens with encased steel cold-formed section and that for reference beam have presented. The experimental results show that the cold-formed steel webs number has a noticeable influence on the structural behaviour of the beam, such as increasing the beam load capacity. The beam load capacity, failure mode and the beam ductility have analysed, and some preparatory criteria for a sufficient outline have presented.

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