Stability check of tapered steel beams in fire

2019 ◽  
Vol 10 (4) ◽  
pp. 373-398 ◽  
Author(s):  
Carlos Couto ◽  
Élio Maia ◽  
Paulo Vila Real ◽  
Nuno Lopes
Keyword(s):  
Design Methodology ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Numerical Models ◽  
Design Methods ◽  
Steel Beams ◽  
Content Type ◽  
Design Methodologies ◽  
Accurate Design ◽  
Improved Design

Purpose The purpose of this paper is to assess whether the adaptation to fire of current proposals/design methodologies at normal temperature is capable of producing accurate predictions of resistance for the out-of-plane stability of tapered beams. Design/methodology/approach The adaptation of these methodologies to fire has been done by accounting for the reduction in steel material properties with the temperature. Results were then compared to FEM calculations by performing GMNIA analyses to determine the ultimate strength of the numerical models and to ascertain the validity and accuracy of the adapted methodologies. Findings Although all methodologies produce safe results at normal temperatures, only the general method is recommended for the safety verification at elevated temperatures, although the data points were overly conservative. This investigation demonstrates the need of proper and accurate design methods for tapered beams at elevated temperatures, which should be the subject of future developments. Research limitations/implications The research in this paper is limited to the adaptation of existing room temperature design methods to fire. Therefore, possible assumptions made during the conception of the initial formulae, which may be valid exclusively for 20ºC, may have been disregarded. Originality/value For the time being, design methodologies for the safety check of tapered beams for the case of fire are inexistent. This paper investigates the adaptation of existing room temperature design to the fire situation by providing insights on their accuracy level, as well as on how to proceed. Finally, a safe design methodology for tapered beams in case of fire is provided until improved design methods are developed.

Lubricant compatibility of FKM seals in synthetic oils

2019 ◽  
Vol 72 (5) ◽  
pp. 557-565
Author(s):  
Dilek Bulut ◽  
Tatjana Krups ◽  
Gerhard Poll ◽  
Ulrich Giese
Keyword(s):  
Polyethylene Glycol ◽  
Design Methodology ◽  
Elevated Temperatures ◽  
Failure Mechanisms ◽  
Standard Test ◽  
New Method ◽  
Static Tests ◽  
Content Type ◽  
Lip Seals ◽  
First Results

Purpose Elastomer seals are used in many applications. They are exposed to lubricants and additives at elevated temperatures, as well as mechanical stresses. They can only provide good sealing function when they have resistance to those factors. There are many elastomer-lubricant compatibility tests based on DIN ISO 1817 in industry. However, they are insufficient and costly. Correlations between the tests and the applications are inadequate. The purpose of this study is investigating lubricant compatibility of fluoroelastomers (FKM) seals in polyethylene-glycol (PG)- and polyalphaolefin (PAO)- based synthetic oils and developing a methodology to predict seal service life. Design/methodology/approach A new compatibility test which is more sufficient in terms of time and cost was developed and compared with a standard test, currently used in industry. Compatibility of FKM radial lip seals with PG- and PAO-based synthetic oils with different additives was investigated chemically and dynamically. Failure mechanisms were examined. Findings The new method and the Freudenberg Flender Test FB 73 11 008 showed similar results concerning damages and similar tendencies regarding wear. The additive imidazole derivative was the most critical. Static tests give indications of possible chemically active additives, but alone they are insufficient to simulate the dynamic applications. Originality/value The paper describes a new method to investigate elastomer-lubricant compatibility and gives first results with a variety of lubricants.

The prediction of the cyclic mechanical behavior of stainless steel 304L at room temperature

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hala Messai ◽  
Salim Meziani ◽  
Athmane Fouathia
Keyword(s):  
Stainless Steel ◽  
Design Methodology ◽  
Room Temperature ◽  
Type Model ◽  
Good Prediction ◽  
304L Stainless Steel ◽  
Content Type ◽  
The Third ◽  
Chaboche Model

Purpose The purpose of this paper is to highlight the performance of the Chaboche model in relation to the database identification, tests with imposed deformations were conducted at room temperature on 304L stainless steel specimens. Design/methodology/approach The first two tests were performed in tension-compression between ±0.005 and ±0.01; in the third test, each cycle is composed of the combination of a compression tensile cycle between ±0.01 followed by a torsion cycle between ±0.01723 (non-proportional path), and the last, uniaxial ratcheting test with a mean stress between 250 MPa and −150 MPa. Several identifications of a Chaboche-type model were then performed by considering databases composed of one or more of the cited tests. On the basis of these identifications, the simulations of a large number of ratchet tests in particular were carried out. Findings The results present the effect of the optimized parameters on the prediction of the behavior of materials which is reported in the graphs, Optimizations 1 and 2 of first and second tests and Optimization 4 of the third test giving a good prediction of the increasing/decreasing pre-deformation amplitude. Originality/value The quality of the model's predictions strongly depends on the richness of the database used for the identification of the parameters.

Design criteria for insulation materials applied in timber frame assemblies

2018 ◽  
Vol 9 (3) ◽  
pp. 252-263 ◽  
Author(s):  
Mattia Tiso ◽  
Alar Just
Keyword(s):  
Cross Sections ◽  
Fire Resistance ◽  
Design Methodology ◽  
Research Study ◽  
Design Model ◽  
Insulation Material ◽  
Content Type ◽  
Insulation Materials ◽  
Timber Frame ◽  
Improved Design

Purpose Insulation materials’ contribution to the fire resistance of timber frame assemblies may vary considerably. At present, Eurocode 5 provides a model for fire design of the load-bearing function of timber frame assemblies with cavities completely filled with stone wool. Very little is known about the fire protection provided by other insulation materials. An improved design model which has the potential to consider the contribution of any insulation material has been introduced by the authors. This paper aims to analyze the parameters that describe in a universal way the protection against the charring given by different insulations not included in Eurocode 5. Design/methodology/approach A series of model-scale furnace tests of floor specimens for three different insulation materials were carried out. An analysis on the charring depth of the residual cross-sections was conducted by means of a resistograph device. Findings The study explains the criteria and procedure followed to derive the coefficients for the improved design model for three insulations involved in the study. Originality/value This research study involves a large experimental work which forms the basis of the proposed design model. This study presents an important step for fire resistance calculations of timber frame assemblies.

scholarly journals Receptacle interacts with consumers’ need for touch to influence tea-drinking experience

2020 ◽  
Vol 122 (9) ◽  
pp. 2981-2992
Author(s):  
Chujun Wang ◽  
Yubin Peng ◽  
Charles Spence ◽  
Xiaoang Wan
Keyword(s):  
Willingness To Pay ◽  
Physical Properties ◽  
Significant Influence ◽  
Material Properties ◽  
Design Methodology ◽  
Room Temperature ◽  
Haptic Perception ◽  
Content Type ◽  
Ceramic Glass ◽  
Tea Drinking

PurposeThis study was designed to investigate how the material properties of the tea-drinking receptacle interact with a participant's motivation and preference for extracting and using information obtained via haptic perception, namely the need for touch (NFT), to influence his or her tea-drinking experience.Design/methodology/approach72 blindfolded participants were instructed to sample room temperature tea beverages served in a cup that was made of ceramic, glass, paper or plastic. They were then asked to rate how familiar they were with the taste of the beverage, to rate how pleasant the taste was and to specify how much they would like to pay for it (i.e. willingness-to-pay ratings).FindingsThe material of the receptacles used to serve the tea exerted a significant influence over the pleasantness ratings of the tea and interacted with the participants' NFT, exerting a significant influence over their willingness to pay for the tea. Specifically, high-NFT participants were willing to pay significantly more for the same cup of tea when it was served in a ceramic cup rather than in a paper cup, whereas the low-NFT participants' willingness to pay for the tea was unaffected by the material of the receptacles.Originality/valueOur findings suggest that consumers may not be equally susceptible to the influence of the receptacle in which tea, or any other beverage, is served. Our findings also demonstrate how the physical properties of a receptacle interact with a consumer's motivation and preference to influence his or her behavior in the marketplace.

scholarly journals Simple methods for identification of radiative properties of highly-porous ceria ceramics in the range of semi-transparency

2017 ◽  
Vol 27 (5) ◽  
pp. 1108-1117 ◽  
Author(s):  
Leonid A. Dombrovsky ◽  
Wojciech Lipinski
Keyword(s):  
Absorption Coefficient ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Radiative Properties ◽  
Spectral Absorption ◽  
Spectral Absorption Coefficient ◽  
Content Type ◽  
Hemispherical Reflectance ◽  
Steady Oscillations ◽  
Highly Porous

Purpose The aim of this paper is to present advanced experimental–numerical methods for identification of spectral absorption and scattering properties of highly porous ceria ceramics in the range of semi-transparency at room and elevated temperatures. Design/methodology/approach At room temperature, a period of quasi-steady oscillations of the sample surface temperature generated in response to recurrent laser heating at fixed values of the maximum and minimum temperature of the irradiated surface is measured along with the normal-hemispherical reflectance. Radiative properties are then identified using a combined heat transfer model. At elevated temperatures, an analytical solution proposed in an earlier study for zirconia ceramics is used to retrieve spectral absorption coefficient of ceria ceramics from the measured normal emittance. Findings and Originality/value This method can be used to obtain small absorption coefficient of ceria ceramics at room temperature. The required measurements of both the normal-hemispherical reflectance and the period of quasi-steady oscillations of the irradiated surface temperature of the ceramics sample between fixed values of the maximum and minimum temperatures can be readily conducted using thermal laboratory equipment. Another method has been suggested for identification of the spectral absorption coefficient of ceria ceramics at elevated temperatures. This method is based on a relation between the measured normal emittance of an isothermal sample and the absorption coefficient.

Design and application of PneuNets bending actuator

2020 ◽  
Vol 92 (10) ◽  
pp. 1539-1546
Author(s):  
Shiwei Zhao ◽  
Daochun Li ◽  
Jinwu Xiang
Keyword(s):  
Finite Element Method ◽  
Regression Models ◽  
Design Methodology ◽  
Maximum Deflection ◽  
Beam Length ◽  
Content Type ◽  
Bending Actuator ◽  
Gauss Process ◽  
Improved Design ◽  
Pressure Magnitude

Purpose The purpose of this study is to propose an improved design of PneuNets bending actuator which aims at obtaining larger deflection with the same magnitude of pressure. The PneuNets bending actuator shows potential application in the morphing trailing edge concept. Design/methodology/approach Finite element method is used to investigate the characteristics of the improved design bending actuator. Multiobjective optimal design of the PneuNets bending actuator is proposed based on the Gauss process regression models. Findings The maximum deflection is obtained when the height of the beams is smaller than half the height of the chambers. The spacing between chambers (beam length) has little effect on the deflection. Larger spacing could be used to reduce the actuator weight. Originality/value With the same pressure magnitude, the deflection of the improved design bending actuator is much larger than that of the baseline configuration. PneuNets bending actuator could increase the continuity of the aerodynamic surface compared to other actuators.

A new economical technique for dyeing polyamide fibre/nanoclay composite with basic dye

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lamiaa Kamal El-Gabry ◽  
Mohamed Fathy Nasr ◽  
Amira Adel Abou El-Kheir
Keyword(s):  
Design Methodology ◽  
Room Temperature ◽  
Physical Method ◽  
Polyamide 6 ◽  
Nylon 6 ◽  
Polyamide Fibre ◽  
Simple Method ◽  
Running Water ◽  
Content Type ◽  
Nano Clay

Purpose This work aims to increase the dyeability of nylon 6 with basic dyeing through the treatment of the fibre with available and cheap nanomaterials, namely; nano bentonite using an economic and simple method. Design/methodology/approach Different amounts of nano clay, namely, nano bentonite were dispersed in distilled water using an ultrasonic homogenizer for 1 h. Nylon fabrics were treated with different concentrations of dispersed nano bentonite (1%, 2%, 3%, 4%, 5% wt/v). After half an hour, the samples were padded using SVETEMA laboratory padding system. The padding pressure was adjusted at 3 bar to allow a pickup of 100%. The padded samples were dried at 80°C for 5 min and cured at 160°C for 3 min using ROACHES laboratory thermos-fixation. The cured samples were then washed with running water and left to dry at room temperature. Findings The obtained results indicated that the modification of polyamide 6 fibres with nano bentonite had a great impact on their dyeing properties. The obtained shades, absorption behaviour and fastness properties were significantly enhanced. Based on these results, it was concluded that polyamide fabrics could be successfully dyed with basic dyes using economical dyeing conditions. Originality/value This paper introduces a new method the loaded the nano-clay on the synthetic fibres, which are nylon 6 to enhance the dyeability with cationic dyes using the physical method without changing the structure of the fibres.

A framework for design methods, models and techniques for product and process development

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Karen Scarlette Sanhueza ◽  
Christopher Nikulin
Keyword(s):  
Design Methodology ◽  
Process Development ◽  
Design Method ◽  
Design Methods ◽  
Content Type ◽  
Wide Range ◽  
Product And Process ◽  
Method Model ◽  
Available Resources

Purpose The purpose of this paper is to address the emerging need to map knowledge and information with a novel classification, suitable to have a clear and integrated overview of the design method, models and techniques from both the sides of product and process. The proposed classification allows to understand main relevance of different design methods, models and techniques according their characteristic and also level in where company usually applied. Design/methodology/approach The authors decided to structure the research into three steps: from the analysis of background literature, in order to draw the main evidences for the development of a novel classification, to their application. First, the papers search related to collect the different methods used in literature. Second, paper characterization which aims to understand main traits and usefulness of design methods, models and tools. Third, the assessment of design methods, models and tools according proposed classification. Findings Each method, model or technique would be more useful according to the context in which is applied. Most of methods and modes can be continuously improving, considering different sub-classification or complement each other, striving to compensate to the extent possible for weakness in any one of the approaches. Research limitations/implications The proposed classification did not deliver absolute results in every analyzed model or techniques, it delivered a wide range of possibilities in every sub-classification, thus the engineers get multiple options to choose depending on its main goal or the available resources. Originality/value The author’s proposal aims at filling a classification gap in the design method literature, which has to plausible in use. The different alternatives can be represented according to a scalable and hierarchical logic embedding also a more structured evaluation of the methods and tools in practice.

Experimental study of two-way post-tensioned flat slabs in fire

2018 ◽  
Vol 9 (3) ◽  
pp. 237-251 ◽  
Author(s):  
Li Zhang ◽  
Ya Wei ◽  
Francis Tat Kwong Au ◽  
Jing Li
Keyword(s):  
Design Methodology ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Testing Temperature ◽  
Structural Behaviour ◽  
Content Type ◽  
Flat Slabs ◽  
Temperature Distributions ◽  
In Fire ◽  
Post Tensioned

Purpose This study aims to investigate the influence of tendon layout, pre-stressing force, bond condition and concrete spalling on the structural behaviour of two-way post-tensioned flat slabs at elevated temperatures. Design/methodology/approach Fire tests of four scale specimens of two-way post-tensioned concrete flat slabs were performed and analysed. Three of them were provided with bonded tendons, while the other was unbonded for comparison. The fabrication of specimens, phenomena observed during testing, temperature distributions, deflections and occurrence of concrete spalling were examined. Findings Different degrees of concrete spalling observed at the soffit had significant effects on the temperature distribution and stress redistribution. This was the major reason for the progressive concrete spalling observed, resulting in loss of structural integrity and stiffness. Originality/value The structural behaviour of two-way post-tensioned concrete flat slabs at elevated temperatures is less understood compared to their one-way counterparts. Therefore, the present study has focused on the structural behaviour of two-way post-tensioned concrete flat slabs with bonded tendons in fire, a field in which relatively little information on experimental work can be found.

Corrosion behaviour of Mn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials

2013 ◽  
Vol 60 (5) ◽  
pp. 234-238
Author(s):  
Yan Jing ◽  
Chao Zhang ◽  
Jun Ma ◽  
Yongzhong Jia
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Design Methodology ◽  
Room Temperature ◽  
Corrosion Behaviour ◽  
Corrosion Process ◽  
Al Alloy ◽  
Content Type ◽  
Explosion Suppression ◽  
Strengthening Phases

PurposeThe purpose of this paper is to prepare the Mn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials, and determine the corrosion behavior of aluminum alloy explosion suppression materials in HCl and NaOH solutions. The different mechanism of corrosion was discussed.Design/methodology/approachIn this paper, Mn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials were prepared, and the electrochemical behavior of the EAESM was studied. The corrosion parameters were calculated and the mechanism of the corrosion process was discussed. The corrosion behavior was characterized by immersion tests and SEM at room temperature.FindingsMn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials have been prepared. SEM, the polarization curves showed that materials have corrosion resistance. The best content of Al alloy is Mn 0.880%, Si 0.135%, Fe 0.383% and Cu 0.0835%.Originality/valueThe results of this investigation show that adding alloying elements can form new strengthening phases that influence the corrosion resistance of alloys.

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