scholarly journals Parametric analysis related to dimensioning of tubular steel columns filled with concrete in a fire situation

2022 ◽  
Vol 15 (2) ◽  
Author(s):  
Fábio Masini Rodrigues ◽  
Armando Lopes Moreno Júnior ◽  
Jorge Munaiar Neto
Keyword(s):  
Mechanical Properties ◽  
Numerical Modeling ◽  
Temperature Field ◽  
Moisture Content ◽  
Numerical Models ◽  
Physical And Mechanical Properties ◽  
Sensitivity Study ◽  
Steel Tube ◽  
Structural Elements ◽  
Steel Columns

ABSTRACT For the dimensioning of structural elements in fire situation, simplified equations and parameters are commonly used in analytical equations or numerical models. More complex equations or simplified values can be chosen by the designer for determine materials properties in high temperature in numerical models, however, numerical modeling can be quite sensitive to the variation of some of the physical and mechanical properties. In this paper, the sensitivity of the numerical model in relation to the values according to the level of simplification chosen was evaluated, presenting an analysis in relation to the results found to contribute to the choice of these parameters and presenting the indications found in the literature. In this sense, this work presents a study of sensitivity to the variation of the values of steel and concrete properties, presented in the Eurocode and Brazilian standards, in addition to the moisture content and emissivity of the surface exposed to fire, for the dimensioning, in a fire situation, of steel tube columns, of circular and square section, filled with concrete. The studies were carried out via numerical modeling developed in the software ABAQUS. It was verified that the resulting emissivity values equal to 0.7 or 0.8, recommended in the literature, are conservative, and the choice of either does not bring significant changes in the temperature field obtained for the structural elements under analysis. It was also verified that the concrete moisture content is a relevant aspect for the formation of its temperature field, also affecting, but to a lesser extent, the steel temperature. Regarding the physical and mechanical properties of the materials, this sensitivity study suggests the adoption of the values from the equations presented in Eurocodes, without simplifications, and with the specific heat and thermal conductivity of the concrete, adopted in accordance with the Eurocode 4.

scholarly journals KUALITAS PAPAN PARTIKEL BERDASARKAN KOMPOSISI SEKAM PADI DAN KAYU SENGON DENGAN VARIASI KADAR PEREKAT

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Dendi Prayoga ◽  
. Dirhamsyah ◽  
. Nurhaida
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Rice Husk ◽  
Raw Materials ◽  
Urea Formaldehyde ◽  
Physical And Mechanical Properties ◽  
Solid Content ◽  
Particle Board ◽  
Rice Husks ◽  
Wood Processing

This research aimed to examine the physical and mechanical properties of particle boards based on the composition of raw materials and adhesive content and know the treatment of the composition of raw materials and the best adhesive content and meet the standard JIS A 5908-2003. The research was conducted at Wood Workshop Laboratory, Wood Processing Laboratory Faculty of Forestry,Tanjungpura University and Laboratory of PT. Duta Pertiwi Nusantara Pontianak. The adhesive used is Urea Formaldehyde with 52% Solid Content. Comparison of the composition of rice husks and sengon varies namely rice husk 50%: sengon 50%, rice husk 60%: sengon 40% and rice husk 70%: sengon 30%  and variations in the levels of UF adhesives, namely 14% and 16%, with target density 0,7 gr/cm3. The particleboard was 30 cm x 30 cm x 1 cm Pressing at temperature 140oC for 8 minutes, with  pressure of 25 kg/cm2. The research results of the study of density and moisture content meet the standards JIS A 5908-2003. The best particle values of rice husk and sengon  with composition a ratio of  rice husk 50%: sengon 50% , 16% adhesive content  16%, with density value of  0,7072 gr/cm3, moisture content 9,1949 %, thick development 12,3210 %, water absorption 68,8270 %, MOE 12110,7273 kg/cm2, MOR 161,0025 kg/cm2, firmness sticky 1,9320 kg/cm2, screw holding strength 62,3124 kg.Keywords : adhesive, composition, particle board, rice husk, sengon

scholarly journals SIFAT FISIK DAN MEKANIK KAYU SALAM (Syzygium polyanthum (Wight)Walp.) BERDASARKAN POSISI KETINGGIAN PADA BATANG

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
. Erma ◽  
Fadiilah H Usman ◽  
. Muflihati
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Average Height ◽  
Class Iii ◽  
Lightweight Construction ◽  
Brown Colour ◽  
Wood Demand ◽  
Selection Of

Physical and mechanical properties of wood is one of the basic properties that need to be known in the selection of wood, because the physical and mechanical properties of wood are not the same height on the stem. Increased wood demand gives the opportunity to use wood that is not yet known for its marketing, one of which is Salam wood (Syzygium polianthum (Wight) Walp). The purpose of this research was to determine the physical and mechanical properties of Salam wood based on the height of the stem so that Salam wood can be optimally utilized by testing based on Classification SNI – 5 PKKI 1961. Methods of making test and test examples based on British Standard Methods No. 373-1957. The results showed that Salam wood has physical properties with an average  brown colour, the moisture content 3,13 % , density  0,58 kg/cm2 , Depreciation 2,59 %. Salam has mechanical properties with an average height position stem from base to tip with Modulus of Elastiscity (MOE)  97.701,54 , Modulus of Rupture (MOR) 659,18  and  Modulus Crushing  Streang 342,86 . Salam can be classified into strong class III and based on its properties and mechanics, it is suitable for use as a lightweight construction and furniture.Keywords: Density, depreciation, MCS, MOE, moisture content, MOR

scholarly journals KUALITAS PAPAN KOMPOSIT LIMBAH KULIT BATANG SAGU (Metroxylon sp) DAN PLASTIK POLIPROPILENA BERDASARKAN JUMLAH LAPISAN PENYUSUN

2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mayang Archila ◽  
Farah Diba ◽  
Dina Setyawati ◽  
. Nurhaida
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Internal Bonding ◽  
Thickness Swelling ◽  
Composite Board ◽  
Average Value ◽  
Composite Layers ◽  
Sago Bark

The objective of this research is to evaluate the effect of the number of composite layers on the quality of the composite board from sago bark waste and plastic waste, and the number of composite layers that produce the best quality on composite board. The composite board is made with size 30 cm x 30 cm x 1 cm. The composition and division of the material was carried out manually with the polypropylene distribution divided into three parts: the front and rear respectively of 15%, and the center 70% of the plastic weight. Target density of composite boards was 0.7 g / cm3. The treatment used is based on the number of layers composing, which is 5 layers, 7 layers, 9 layers, 11 layers and 13 layers. After mixed the sago bark particle and waste of polypropylene, the materials then compressed with hot press at 180oC with pressure about ± 25 kg / cm2 for 10 minutes. The composite boards then tested the quality included physical and mechanical properties. Testing of physical and mechanical properties refers to JIS A 5908-2003 standard. Physical properties consist of density, moisture content, thickness swelling, and water absorption. Mechanical properties consist of modulus of rupture, modulus of elasticity, internal bonding, and modulus of screw holding strength. The study used a completely randomized design experiment consisting of 5 treatments and 3 replications. The results showed the average value of composite density was range between 0.6962 – 0.7896 g/cm3, the moisture content was range between 4.3388 % - 6.8066%, the thickness swelling was range between 8.2605% - 11.9615%, and water absorption was range between 17.2380% - 22.3867%. The average value of modulus of rupture was range between 60,0632 kg/cm2 – 64,4068 kg/cm2, the modulus of elasticity was range between 17935,1813g/cm2 – 32841,8278 kg/cm2, the internal bonding was range between 1,9268 kg/cm2  - 5,4119 kg/cm2, and the modulus of screw holding strength was range between 78,2530 kg/cm2 – 92,9677 kg/cm2. The composite board made from sago stem bark waste and polypropylene waste plastic with 13 layers treatment is the best composite board and fulfilled the JIS A 5908-2003 standard. Keywords: bark of sago, composite boards, layer of composite, polypropylenes plastic, waste

scholarly journals Effect of Moisture Content on Selected Physical and Mechanical Properties of Two Varieties of Tigernut (Cyperus spp)

2013 ◽  
Vol 2 (6) ◽  
pp. 24
Author(s):  
A. S. Oyerinde ◽  
A. P. Olalusi
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Bulk Density ◽  
Average Length ◽  
Physical And Mechanical Properties ◽  
Static Friction ◽  
Angle Of Repose ◽  
Tuber Weight ◽  
Porosity Coefficient ◽  
Effect Of Moisture

<p>The effect of moisture content on some physical and mechanical properties of two varieties of tigernuts (<em>Cyperus esculentus</em>) was investigated. These properties include: geometric dimensions, linear dimensions, 1000 tuber weight, bulk density, tuber size, sphericity, angle of repose, porosity, coefficient of static friction and compressive strength. The moisture content levels used were 20, 25, 30, 35 and 40% wet basis (wb), and the two tigernut varieties used were yellow and brown types. The linear dimension, geometric diameter, sphericity, 1000- tuber weight, bulk density and angle of repose in both varieties increased with increasing moisture content. The average length, width and thickness of the yellow variety increases more than the brown variety at the determined moisture contents. True density of the yellow variety increased while the brown variety decreased with increase in moisture content. The porosity of the yellow variety reduces with increase in moisture content from 45.95 at 20% mc to 42.4 at 40% mc, while the brown variety decreased from 42.72 at 20% mc to 30.77 at 40% moisture content. The yellow variety had bigger size tubers than the brown variety and this has serious implications in packing, handling and transportation issues.</p>

scholarly journals Axial Compression Performance of Square Thin Walled Concrete-Filled Steel Tube Stub Columns with Reinforcement Stiffener under Constant High-Temperature

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1098 ◽  
Author(s):  
Xuetao Lyu ◽  
Yang Xu ◽  
Qian Xu ◽  
Yang Yu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Bearing Capacity ◽  
Numerical Models ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Concrete Filled Steel Tube ◽  
Finite Element Software ◽  
Thin Walled

This study investigated the axial compressive performance of six thin-walled concrete-filled steel tube (CFST) square column specimens with steel bar stiffeners and two non-stiffened specimens at constant temperatures of 20 °C, 100 °C, 200 °C, 400 °C, 600 °C and 800 °C. The mechanical properties of the specimens at different temperatures were analyzed in terms of the ultimate bearing capacity, failure mode, and load–displacement curve. The experiment results show that at high temperature, even though the mechanical properties of the specimens declined, leading to a decrease of the ultimate bearing capacity, the ductility and deformation capacity of the specimens improved inversely. Based on finite element software ABAQUS, numerical models were developed to calculate both temperature and mechanical fields, the results of which were in good agreement with experimental results. Then, the stress mechanism of eight specimens was analyzed using established numerical models. The analysis results show that with the increase of temperature, the longitudinal stress gradient of the concrete in the specimen column increases while the stress value decreases. The lateral restraint of the stiffeners is capable of restraining the steel outer buckling and enhancing the restraint effect on the concrete.

Measurement of Physical and Mechanical Properties of Russian Olive (Elaeagnus Angustifolia L.) Fruit

2016 ◽  
Vol 12 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Mohammad Hossein Nadian ◽  
Mohammad Hossein Abbaspour-fard
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Loading Rate ◽  
Geometric Mean ◽  
Testing Machine ◽  
Physical And Mechanical Properties ◽  
Angle Of Repose ◽  
Shear Mode ◽  
Russian Olive ◽  
Double Shear

Abstract The effect of moisture content on some properties of two varieties (Meymeh and Maragheh) of Russian olives was studied. The physical and mechanical properties including: dimensions, geometric mean diameter, thousand mass, volume, sphericity, surface area, true and bulk densities, porosity, angle of repose, coefficient of friction, rupture force, and rupture energy. The changes of moisture content levels from 17% to 25% (w.b.) indicated a statistically significant effect on all studied physical properties, except bulk density for Russian olive fruits. Shearing force was applied to the fruit using a testing machine in double shear mode. Shear strength and shearing energy increased with increase of loading rate; however, they were higher in Meymeh variety than Maragheh variety. Therefore, the lowest loading rate, with up to about 10 mm/min is desirable to design a suitable pulverizing mill in the herbal medicine industries.

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