scholarly journals THE HEATING RATE IMPACT ON PARAMETERS CHARACTERISTIC OF STEEL BEHAVIOUR UNDER FIRE CONDITIONS

2006 ◽  
Vol 12 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Zoja Bednarek ◽  
Renata Kamocka
Keyword(s):  
Heating Rate ◽  
Steel Structure ◽  
Steel Structures ◽  
Absolute Temperature ◽  
Strength Analysis ◽  
Test Results ◽  
Heating Rates ◽  
Linear Temperature ◽  
Strength Tests

The behaviour of steel structure components within a high temperature field depends not only on the absolute temperature, but also on the temperature vs time function and on the heating rate, dT/dτ. The research objective is the determination of the heating rate impact on selected strength parameters of structural steels. Tests were performed under conditions of a linear temperature increase with different heating rates and with a constant stress value, σ/fy . After strength tests, the samples were subjected to metallography. Test results proved that the heating rate makes a significant impact on parameters that determine the steel structure bearing capacity at higher temperatures and that the heating rate should be accounted for in the strength analysis of steel structures exposed to high temperatures.

Определение требуемой толщины вспучивающегося огнезащитного покрытия на стальных конструкциях для заданных пределов огнестойкости

2020 ◽  
Author(s):  
Yury Shebeko ◽  
Aleksey Shebeko ◽  
Andrey Zuban
Keyword(s):  
Fire Resistance ◽  
Confidence Level ◽  
Fire Retardant ◽  
Steel Structure ◽  
Steel Structures ◽  
Mean Square ◽  
Mean Square Deviation ◽  
R Value ◽  
The Given

Проанализирована взаимосвязь разброса значений пределов огнестойкости стальных конструкций со вспучивающимися огнезащитными покрытиями и соответствующего этому разбросу интервала толщины огнезащитного покрытия. Предложена методика, на основании которой может быть осуществлен выбор необходимой толщины огнезащитного покрытия в зависимости от заданных значений дисперсии предела огнестойкости и приведенной толщины конструкции при заданной доверительной вероятности.An analysis of a relationship between fire resistance limits scatter for steel structures coated with intumescent fire retardant coating and an appropriate interval of thicknesses of the coating was carried out. A methodology for the determination of this relationship was proposed. This methodology was tested on a practical example. A steel structure with a reduced thickness of 6 mm was considered. A typical dependence of the required thickness of the structure was taken into account. A ratio of a mean square deviation of the fire resistance limit to this limit was accepted to be equal 0.1. Using these values an appropriated interval of the thicknesses of the intumescent fire retardant coating was determined. This interval can be calculated for any given confidence level. Boundaries of this interval can be not symmetric in relation to the value of the normative thickness of the fire retardant coating. The proposed methodology can be used for the determination of the required thicknesses of the intumescent fire retardant coatings on steel structures for the given r value, reduced thickness of the structure and the confidence level.

Elastic Strength of Defective Steel Bolt Group under Eccentric Load Design

2018 ◽  
Vol 773 ◽  
pp. 299-304
Author(s):  
Jen Jen Yang ◽  
Kun Ze He ◽  
Wei Ting Hsu
Keyword(s):  
Geometric Distribution ◽  
Design Method ◽  
Group Analysis ◽  
Steel Structure ◽  
Steel Structures ◽  
Strength Analysis ◽  
Material Strength ◽  
Eccentric Load ◽  
Critical Position ◽  
Design Strength

Steel bolt groups are often used for joining steel structures. The design strength of the steel bolt group is related to the geometric distribution, the eccentric load distance, the material strength and the load angle, thus making the analysis complicated and not easy for the user. The existing analysis methods are two kinds of elasticity and ultimate analysis. Both methods consider the stress distribution of each steel bolt and find the steel bolt at the critical position is obtained, the design load analysis is deduced. This study will consider the geometric distribution of steel bolting group affected, for a row, two rows, three rows and four rows of bolt group, considering different eccentric distance and angle of influence. Using a simple elastic analysis method to Studied the strength analysis results produced when a corner bolt is damaged due to a defect. The results show that the greater the eccentric load distance, the lower the design strength, and the load change on the vertical is more obvious than the horizontal. When the corner of the steel bolt group is removed, its design strength is likely to decrease, but at low eccentricity distance and large angles, the strength of the complete bolt is higher. This study organizes the design method of steel bolts and reviews the geometric rules of the bolt group analysis. It founded that the regular geometry needs to be reviewed in the case of large eccentric loads with small eccentricities. This study for the bolt connections strength of a certain understanding and awareness, expect the future for the safety of steel structure contribute.

APPLICABILITY OF A NEW SURFACE PREPARATION METHOD FOR STEEL STRUCTURE USING LASER

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Hiroshi Ogami ◽  
Katashi Fujii ◽  
Yukio Manabe ◽  
Kohei Ota ◽  
Asuo Yonekura
Keyword(s):  
Preparation Method ◽  
Surface Condition ◽  
Surface Preparation ◽  
Steel Structure ◽  
Steel Structures ◽  
Laser Cleaning ◽  
Coating Film ◽  
Test Results ◽  
Corrosion Prevention ◽  
Accelerated Corrosion

Surface preparation is very important in re-painting of steel structures so as to extend the effective term of corrosion prevention. Though grinding or blasting have been widely used to remove rust and old coating film on steel surface, both these methods have difficulty in completion of rust-removal and cause some problems such as dust scattering, noise, etc. In order to solve these problems, this paper presents the laser cleaning method which instantaneously sublimes/evaporates the rust on the surface of steel structure. The authors investigate the effects and the applicability of laser cleaning using the specimens made by accelerated corrosion method. The test results confirmed that the laser cleaning can remove the rust almost much as using sand blast, and the salt on the surface of steel can also be evaporated as good as the rust. Moreover, this method seems can be applied on wet surface condition because the moisture and water on the surface of steel can also be evaporated.

Determination of Solidification Parameters Used for the Prediction of the Thixoformability of Several Steel Alloys

2006 ◽  
Vol 116-117 ◽  
pp. 54-57 ◽  
Author(s):  
Jacqueline Lecomte-Beckers ◽  
Ahmed Rassili ◽  
Marc Robelet ◽  
Claude Poncin ◽  
R. Koeune
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heating Rate ◽  
Liquid Fraction ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Steel Alloys ◽  
Fraction Versus ◽  
Solidification Parameters ◽  
Industrial Heating

This paper focuses on the liquid fraction curves of several steels and the correlation between liquid fraction, temperature and heating rate. The work has been performed along two main axes. First, the solid fraction versus temperature has been obtained experimentally by differential scanning calorimetry (DSC), limited to low heating rates. Then, a shift of the liquid fraction curves has been noticed at high industrial heating rates. The quantification of this effect could not be carried out by DSC and required the elaboration of another experimental device.

scholarly journals Solid-Solid Phase Transformations and Their Kinetics in Ti-Al-Nb Alloys

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1991
Author(s):  
Benedikt Distl ◽  
Katja Hauschildt ◽  
Florian Pyczak ◽  
Frank Stein
Keyword(s):  
Phase Transformations ◽  
Heating Rate ◽  
Solid Phase ◽  
Thermal Analyses ◽  
Order Type ◽  
Heating Rates ◽  
Transformation Temperatures ◽  
Intermetallic Materials ◽  
Reduction Of Co2

The application of light-weight intermetallic materials to address the growing interest and necessity for reduction of CO2 emissions and environmental concerns has led to intensive research into TiAl-based alloy systems. However, the knowledge about phase relations and transformations is still very incomplete. Therefore, the results presented here from systematic thermal analyses of phase transformations in 12 ternary Ti-Al-Nb alloys and one binary Ti-Al measured with 4–5 different heating rates (0.8 to 10 °C/min) give insights in the kinetics of the second-order type reaction of ordered (βTi)o to disordered (βTi) as well as the three first-order type transformations from Ti3Al to (αTi), ωo (Ti4NbAl3) to (βTi)o, and O (Ti2NbAl) to (βTi)o. The sometimes-strong heating rate dependence of the transformation temperatures is found to vary systematically in dependence on the complexity of the transformations. The dependence on heating rate is nonlinear in all cases and can be well described by a model for solid-solid phase transformations reported in the literature, which allows the determination of the equilibrium transformation temperatures.

scholarly journals Shock Wave Attenuation Characteristics of Aluminum Foam Sandwich Panels Subjected to Blast Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jinglin Xu ◽  
Jianqing Liu ◽  
Wenbin Gu ◽  
Xin Liu ◽  
Tao Cao
Keyword(s):  
Shock Wave ◽  
Mild Steel ◽  
Polyvinylidene Fluoride ◽  
Sandwich Structure ◽  
Aluminum Foam ◽  
Wave Attenuation ◽  
Steel Structure ◽  
Steel Structures ◽  
Test Results ◽  
Attenuation Rate

Comparative experiments were conducted with two different structures to study the mechanism of aluminum foam sandwich attenuating blast shock wave. The sandwich structure is composed of “steel–aluminum foam–steel,” and the mild steel structure is composed of “steel–steel.” In the experiment, the polyvinylidene fluoride transducers were used to directly test the load of stress wave between different interfaces of sandwich and mild steel structures. The strain of back sheet was simultaneously measured using high-precision strain gauge. The accuracy of the test results was verified by Henrych’s formula. Experimental results show that the wave attenuation rate on the mild steel structure is only 11.3%, whereas the wave attenuation rate on the sandwich structure can exceed 90%. The interface effect is clearly a more crucial factor in the wave attenuation. The peak value of back sheet strain in the mild steel structure is much higher than the sandwich structure. The apparent overall “X” crushing band is produced in the aluminum foam core, and scanning electron microscope (SEM) observation clearly shows the collapse of the cell wall. Experiments on the sandwich structure with different aluminum foam densities indicate that increasing the relative density results in increased attenuation capability of the aluminum foam and decreased attenuation capability of the sandwich structure. Experiments on the sandwich structure with different aluminum foam thickness indicate that increasing the thickness results in increased attenuation capability of the aluminum foam and the sandwich structure.

An FT-IR Method for Performing Dynamic Kinetic Experiments

1988 ◽  
Vol 42 (4) ◽  
pp. 655-658 ◽  
Author(s):  
Randy W. Snyder ◽  
C. Wade Sheen
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Heating Rates ◽  
Calculated Activation Energy ◽  
Ft Ir ◽  
Calculated Activation

A method is shown for the determination of kinetic parameters from dynamic FT-IR experiments. The effect heating rate has on the reproducibility of the calculated activation energy is discussed. The curing of PMDA/ODA polyimide at several heating rates is given as an example.

Research and Simulation on Strengthening Steel Structure with Carbon Fiber Sheet

2012 ◽  
Vol 232 ◽  
pp. 82-85
Author(s):  
Yang Hou Chen
Keyword(s):  
Carbon Fiber ◽  
Concrete Structures ◽  
Steel Structure ◽  
Steel Structures ◽  
Test Results ◽  
Element Analysis ◽  
Cfrp Composite ◽  
Fiber Sheet ◽  
Strengthening Technique ◽  
Carbon Fiber Sheet

Carbon Fiber-Reinforced Polymer(CFRP) Composite Sheets Have Gained Popularity as a Viable Strengthening Technique for Fractured Concrete Structures. the Behavior of Carbon Fiber Sheet Materials to Cracked Steel Structures Is Quite Different from that of Concrete Structures. More and More Attention Are Paid to Research on Strengthening Steel Structure with Carbon Fiber Sheet. this Paper Presents the Study on the Steel Structure Bonded with Carbon Fiber Sheets. the Infinite Element Analysis Software ANSYS Is Used to Analyze the Effects of Strengthening a Steel Structure. and the Test Results of Crack Specimens Strengthened by Carbon Fiber Sheet Are Given. the Finite Element Results and Test Results Show that the Using of Carbon Fiber Sheet Can Improve Load Bearing of Structure and its Fatigue Life.

scholarly journals “Can the Tower be Retained”

2014 ◽  
Vol 2 (1) ◽  
pp. 65-78
Author(s):  
Katalin Horváth
Keyword(s):  
Structural Steel ◽  
High Stress ◽  
Steel Structure ◽  
Bolted Joints ◽  
Industrial Plant ◽  
Strength Analysis ◽  
Wind Effects ◽  
Complex Study

Abstract This paper focuses on the analysis of two towers of an industrial plant exhibiting extreme deflection during service loads under heavy wind conditions. The towers are 90 m and 35 m in height, respectively and are interconnected with structural steel operating platforms. The nuts have flown off at some bolted joints in the interconnecting steel structure due to high stress induced by deflections. The deflections measured at the structural steel towers had nearly twice the value permitted by the respective standard in the case of the 90 m high tower and approached the value permitted by the standard in the case of the 35 m high tower. The herein detailed complex study - covering the strength analysis of the towers, the analysis of wind effects, and the review of the foundations - has been elaborated in order to determine the causes and consequences of the experienced deflections at the plant as well as to conclude the eventual actions to be taken. The primary consideration for the conduction of the tests and analyses the determination of the eventual actions to be taken was to retain the towers and not to have them demolished.

Reasons for the formation of crack-like defects in 09Г2С heavy plate steel for tank steel structures

2020 ◽  
Vol 10 (5) ◽  
pp. 479-489
Author(s):  
Vitaly М. Goritsky ◽  
◽  
Georgy R. Shneyderov ◽  
Eugeny P. Studenov ◽  
Olga A. Zadubrovskaya ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Defect Formation ◽  
Steel Structures ◽  
Controlled Rolling ◽  
Plate Steel ◽  
Heavy Plate ◽  
Oil Storage ◽  
Magnetic Inspection ◽  
Metal Microstructure

Determination of causes of crack-like defects in the heavy plate steel 09Г2С is a crucial task, the solution of which is aimed at improving the mechanical safety of oil storage steel vertical tanks. In order to determine the causes for the formation of a group of crack-like defects oriented towards rolling, revealed during grinding and magnetic inspection of the tank wall surface near the vertical weld, the analysis of the chemical composition and testing of the mechanical properties of heavy plate steel were carried out, including the determination of the anisotropy of impact toughness in the temperature range from +20 to –75 °С, analysis of metal microstructure in the area of defect formation on transversal sections and rolled surface. Impact bending tests of 09Г2С heavy plate steel after controlled rolling in longitudinal and transverse directions showed no anisotropy of impact toughness, as well as high purity of steel as for sulfur and titanium, which at higher content causes impact toughness anisotropy. The revealed features of metal microstructure near the defects made it possible to conclude that the crack-like defects were formed during the rolling of gas bubbles at the stage of preparing semi-finished rolled products for finishing rolling. One of the possible methods to prevent such defects from getting into finished rolled products is the use of automated systems of visual inspection of rolled products in the manufacturing process.

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