Glass in building. Determination of the bending strength of glass

2015 ◽  
Keyword(s):  
Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3979
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Karolina Miedzińska ◽  
Krzysztof Strzelec

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.


2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Uiatan Aguiar Nogueira ◽  
Matilde Batista Melo ◽  
Daniel De Lima Araujo

RESUMO: A Análise de elementos estruturais, realizadas durante as etapas de projeto de uma estrutura, é parte fundamental para garantia de bom desempenho e estabilidade do sistema estrutural. Na execução de algumas estruturas, como as coberturas em edificações, é usual o emprego de perfis leves de aço formados a frio devido ao seu baixo peso. Esta pesquisa tem por objetivo avaliar a eficiência estrutural desses perfis quando comparados, por exemplo, aos perfis soldados compactos. Para tanto, foram realizados ensaios de flexão em quatro vigas biapoiadas submetidas a duas forças concentradas, de forma a se obter flexão pura no meio do vão das vigas. Estas foram instrumentadas para a determinação da sua rigidez e da sua resistência à flexão. A principal contribuição deste trabalho é demonstrar a eficiência estrutural de perfis formados a frio em seção caixa submetidos à flexão em comparação com perfis de seção tipo “H” soldados. ABSTRACT: The analysis of structural elements, in a structure’s design, is an essential step to ensure good performance and stability of the structural system. In any types of structures, such as roofing in buildings, it’s usual using cold-formed steel beams due to their small weight. This research seeks to evaluate the structural efficiency of cold-formed steel beams when compared, for example, to compact welded steel beams. Thus, bending tests were performed in four simply supported beams submitted to two concentrated loads, in order to obtain pure flexure at the mid-span of the beams. These beams were instrumented for the determination of their rigidity and bending strength. The results showed that the cold-formed steel beam, box-shaped, presented structural efficiency similar to the welded steel beam “H” shaped.


2019 ◽  
Vol 31 ◽  
pp. 26-37
Author(s):  
Hassan M. Hassan Ali ◽  
Koh Heng Boon ◽  
Rasheed Altouhami ◽  
Ng Wei Shen ◽  
Ashraf Radwan ◽  
...  

Mortar is a workable paste essential in civil and building construction. Mortar works as binding material extensively use for masonry unit in construction. The global consumption of natural sand is very high, due to the extensive use of concrete or mortar. Natural sand deposits are being depleted and causing a serious threat to the environment as well as the society. Sandy clay has been widely use in preparing the mortar for masonry work. The aim of this research was to study the bending strength of built-up masonry prism using sandy clay mortar. There were two series of mortar containing 0% and 100% of sandy clay had been prepared. The sandy clay was used to replace natural fine aggregate. Mortar with 0% sandy clay was the control mix containing 100% natural fine aggregate. Three types of masonry unit consist of clay brick, cement brick and lightweight brick were used in this study. The masonry units were combined together using the mortar joints to form the masonry prisms. 100% natural fine sand and 100% sandy clay mortar were prepared and used for the joints. Built-up masonry prisms with single and double joints of mortar. Also, the masonry prisms contained from a length ranging from 390 mm to 610 mm were prepared using the mortar joints. The thickness of the mortar joint which was used in this study was 10 mm, 20 mm and 30 mm. the prisms had been tested for the determination of bending strength at 28 days. The experimental results were analyzed to investigate the effect of sandy clay and thickness of mortar on the bending strength of built-up masonry prism. Results had shown that masonry prism built with sandy clay mortar has higher bending strength compare to the fine sand mortar. Clay brick exhibited highest bending strength with sandy clay mortar which was 38.28 N/mm2and cement brick had the lowest bending strength which was 18.8 N/mm2, while cement brick achieved optimum bending strength. In addition, the highest collapse and deflection achieved by clay brick and cement brick whereas the lowest value of collapse and deflection was by lightweight brick. The highest percentage of increment in terms of collapse load was determined to be 13.73% for sandy clay mortar prism. Hence, 100% sandy clay mortar is suitable to be used in masonry works.


2009 ◽  
Vol 409 ◽  
pp. 185-192
Author(s):  
Lucia Hegedűsová ◽  
Alexandra Kovalčíková ◽  
Monika Kašiarová ◽  
Ján Dusza

The paper deals with the determination of the characteristic strength and the Weibull modulus m of Si3N4 and SiC ceramic materials using conventional four-point bending and unconventional contact tests between opposite rollers and opposite spheres. Ceramographic and fractographic methods were used for the characterization of strength degrading defects represented by processing flaws and by cracks of different types arising during the loading. The processing flaws influenced the Weibull parameters mainly in the bending mode, and the strength and its scatter in contact modes was influenced by lateral, median and contact end cracks, originated during the contact test using rollers, and by cone cracks originated during the contact test using spheres.


2004 ◽  
Vol 127 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Kadir Cavdar ◽  
Fatih Karpat ◽  
Fatih C. Babalik

This paper presents a method for the determination of bending stress minimization of involute spur gears. A computer program has been developed to investigate the variation of bending stress and contact ratio depending on the pressure angle on the drive side. Since asymmetric tooth is not standard, the tooth model, which was introduced by DIN 3990/Method C and ISO/TC 60, has been adjusted for asymmetric tooth by the authors. The determination of the tooth form and stress concentration factors for asymmetric tooth has been accomplished for each different parameter (pressure angles, tool radius, rack shift, etc.). The sample results, which were obtained by using a developed computer program, are illustrated with numerical examples.


OPSI ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 66
Author(s):  
Sutrisno Sutrisno Sutrisno ◽  
Dyah Rachmawati Lucitasari

Kasongan Ceramic UKM Center is an association of UKM which makes goods made from clay. Kasongan Ceramic UKM Center, located in Bantul Regency, DIY. The problem that is often experienced by Kasongan Ceramics Center is that products that are often cracked, warped, and easily brittle. The total production of Kasongan UKM Center from September 2019 to February 2020 was 32,256 units, with the number of defective products amounting to 3,873 or 12% of the total production. Based on the studies that have been done, it can be concluded that the defects of cracks, curling, and brittleness that occur are one of them caused by the less than optimal flexural strength of the ceramic products produced. To maximize the flexural strength of the ceramic products produced, the optimal ceramic manufacturing process parameters will be determined using the Taguchi method. To maximize the flexural strength in the process of making ceramics using the Taguchi method, it is necessary to do an experimental design. The first thing to do is to determine the controlled factors and levels in the ceramic manufacturing process that affect the flexural strength. After that determine a suitable orthogonal array and perform experiments based on the specified orthogonal array. The experimental results will be tested for its flexural strength in the laboratory. The resulting flexural strength data will be processed to determine the optimal ceramic manufacturing process parameters that maximize the bending strength of ceramics. Based on the data processing carried out, it is found that the optimal ceramic-making process parameters at the Kasongan Ceramics UKM Center that maximize flexural strength are the composition of 3 parts Godean clay, 3 parts Kasongan clay composition, 1 part sand composition, and burning using an open tub. 


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