scholarly journals Studying the influence of the cross section height on the distribution of the internal efforts of wooden glued beams

2019 ◽  
Vol 135 ◽  
pp. 03048
Author(s):  
Sergei Prokhorov
Keyword(s):  
Cross Section ◽  
High Strength ◽  
Large Error ◽  
Environmental Friendliness ◽  
High Rise ◽  
Reinforced Beams ◽  
Flexural Member ◽  
Strength And Stiffness ◽  
Capital Construction ◽  
Wooden Structures

Since ancient times, wooden structures have been used by man for the construction of buildings and facilities. For many centuries, the structural elements of buildings and facilities made of wood have been the main ones, and still have broad prospects for use in modern capital construction, as they have sufficient high strength and stiffness, are reliable and durable, while having a small mounting weight. In particular, a number of Western countries are already erecting high-rise buildings using a framework of laminated wood constructions. The indisputable advantage of wooden structures is environmental friendliness. However, with all the harmony of the wood structure, its tracheid’s are not standard, which is the main reason for the variability of its mechanical properties. With alteration of a cross-section of flexural member, the nature of the load distribution, as well as the nature of the fracture, changes. An additional factor that affecting the force distribution is the nature of the reinforcement and methods of the reinforcement fixing methods. The methods used to calculate the “low” reinforced beams often give a large error in the calculation of “high” beams. In the work, a rational methodology for calculating wooden glued reinforced beams with symmetrical reinforcement is determined.

scholarly journals INFLUENCE OF CROSS SECTION HEIGHT AND NATURE OF REINFORCING GLUED WOODEN BEAMS ON THE DISTRIBUTION OF INTERNAL EFFORT

2019 ◽  
Vol 4 (7) ◽  
pp. 33-40
Author(s):  
С. Прохоров ◽  
Sergey Prokhorov
Keyword(s):  
Cross Section ◽  
High Strength ◽  
Structural Elements ◽  
High Rise ◽  
Reinforced Beams ◽  
Environmental Requirements ◽  
Definition Of ◽  
Natural Symmetry ◽  
Capital Construction ◽  
Wooden Structures

The main trends of modern construction is the production and use of light construction structures, which can significantly accelerate the construction of building objects. At the same time, the use of structural and finishing materials that meet modern environmental requirements is important. Structural elements of buildings have dominated for many centuries and have broad prospects for use in modern capital construction: they have high strength and rigidity; they are reliable and durable and have a low installation weight. In particular, in a number of Western countries, high-rise buildings are already being built using a frame made of glued wooden structures. Despite the natural symmetry of coniferous woods structure, its non-standard tracheids are the main reason for the variability of its mechanical properties. In addition, when calculating glued reinforced structures, it is necessary to take into account the so-called "scale effect" when calculating the bent glued wooden elements. The applied methods for the calculation of "low" reinforced beams sometimes give an error in the calculation of "high" beams. In this paper, the definition of a more rational method of calculating the "high" beams with symmetrical reinforcement and comparison of options for reinforcing such beams are performed

scholarly journals Stress-strain condition of reinforced timber structures with artificially created weakenings

2020 ◽  
Vol 175 ◽  
pp. 11003
Author(s):  
Tatiana Shchelokova ◽  
Evgeny Tararushkin
Keyword(s):  
Cross Section ◽  
Raw Material ◽  
Low Grade ◽  
Building Structures ◽  
Stress Strain ◽  
Main Research ◽  
Russian Economy ◽  
Reinforced Beams ◽  
Wooden Structures

About 20% of the world’s timber grows in Russia, but the huge forest-raw material potential is used inefficiently. The forest industry is modestly represented and the Russian economy brings minimal income. In recent decades, more serious requirements have been placed on building structures, but the quality of lumber has been steadily declining throughout the world. The modern woodworking industry improves the quality of lumber by removing unacceptable wood defects, followed by end gluing of boards to a “mustache” or “toothed joint”. Of all types of joints of wooden elements, the notched adhesive or “toothed joint” provides the best use of their bearing capacity, since it causes less weakening of the cross-section of the elements, which is characteristic of other methods of joining (nailing, bolting, etc.). But along with this, the results of numerous tests showed that in conditions of mass production, the main place of destruction is the “toothed joint” or gear joints (about 50%) in the layers of the structures of the stretched zone. The presence in the most stressed layers of the stretched zone of the bent glued elements of the gear joints leads, as a rule, to the destruction of the elements precisely because of these weaknesses. As a result, there is a need for a more detailed and indepth study of the effect of artificially created weakenings on the work of wooden structures. One of the methods for improving the performance of structures made of low-grade wood is their reinforcement. The purpose of the research is to determine the degree of influence of some artificially created types of attenuation on the stress-strain state of reinforced wooden beams. The main research methods: mathematical calculations, computer modeling in the PC “COSMOS / M”, experiment. The experimental design technique is given [27]. The results are presented in the form of graphs and tables. The main conclusions made after the work: deformability in reinforced beams is 15-20% lower than in unreinforced ones; the destruction of reinforced beams with a weakened cross section occurs without a sharp collapse, due to the supporting effect of the reinforcement in the stretched zone and the reliable connection of the reinforcement with the wood, which provides an adhesive joint up to the destruction of the wood. The safety factor of reinforced wooden structures varies from 3.00 to 5.00.

scholarly journals The strength of compressed structures with CFRP materials reinforcement when exceeding the cross-section size

2018 ◽  
Vol 33 ◽  
pp. 02060 ◽  
Author(s):  
Petr Polskoy ◽  
Dmitry Mailyan ◽  
Sergey Georgiev ◽  
Viktor Muradyan
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
High Strength ◽  
Material Consumption ◽  
High Rise ◽  
Labour Costs ◽  
Section Size ◽  
Strength And Deformation ◽  
The Cross ◽  
Composite Reinforcement

The increase of high-rise construction volume or «High-Rise Construction» requires the use of high-strength concrete and that leads to the reduction in section size of structures and to the decrease in material consumption. First of all, it refers to the compressed elements for which, when the transverse dimensions are reduced, their flexibility and deformation increase but the load bearing capacity decreases. Growth in construction also leads to the increase of repair and restoration works or to the strengthening of structures. The most effective method of their strengthening in buildings of «High-Rise Construction» is the use of composite materials which reduces the weight of reinforcement elements and labour costs on execution of works. In this article the results of experimental research on strength and deformation of short compressed reinforced concrete structures, reinforced with external carbon fiber reinforcement, are presented. Their flexibility is λh=10, and the cross-section dimensions ratio b/h is 2, that is 1,5 times more, than recommended by standards in Russia. The following research was being done for three kinds of strained and deformed conditions with different variants of composite reinforcement. The results of the experiment proved the real efficiency of composite reinforcement of the compressed elements with sides ratio equal to 2, increasing the bearing capacity of pillars till 1,5 times. These results can be used for designing the buildings of different number of storeys.

Storage Modulus Capacity of Untreated Aged Arenga pinnata Fibre-Reinforced Epoxy Composite

2013 ◽  
Vol 393 ◽  
pp. 171-176 ◽  
Author(s):  
Muhamad Faris Syafiq Khalid ◽  
Abdul Hakim Abdullah
Keyword(s):  
Storage Modulus ◽  
Epoxy Composite ◽  
Flexural Modulus ◽  
Accelerated Aging ◽  
High Strength ◽  
Mechanical Analysis ◽  
Natural Fibre ◽  
Raw Material ◽  
Environmental Friendliness ◽  
Strength And Stiffness

Research on natural fibre is keeps on going due to their high strength and stiffness, natural availability, and environmental friendliness. In addition, they are also recyclable, renewable and low in raw material cost. This study was done to determine the performance of aging Arenga Pinnata fibre-reinforced epoxy composite (APFREC) on varying temperature. The specimens were aged from 0 to 90 days by using accelerated aging process and were subjected to dynamic mechanical analysis (DMA) and flexural modulus evaluation. The results have shown that specimens with lower aging days have higher storage modulus initially, that is at below 70 °C but as the temperature increase, its storage modulus drastically decrease in comparison to a more aged specimen. Result of storage modulus at low temperature is similar flexure modulus evaluation. The research indicates that aging APFREC specimens has better thermal resistance.

scholarly journals Are We Able to Print Components as Strong as Injection Molded?—Comparing the Properties of 3D Printed and Injection Molded Components Made from ABS Thermoplastic

2021 ◽  
Vol 11 (15) ◽  
pp. 6946
Author(s):  
Bartłomiej Podsiadły ◽  
Andrzej Skalski ◽  
Wiktor Rozpiórski ◽  
Marcin Słoma
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Mechanical Strength ◽  
Cross Section ◽  
Fused Deposition Modeling ◽  
High Strength ◽  
Large Cross Section ◽  
Fused Deposition ◽  
Injection Molded ◽  
The Cross

In this paper, we are focusing on comparing results obtained for polymer elements manufactured with injection molding and additive manufacturing techniques. The analysis was performed for fused deposition modeling (FDM) and single screw injection molding with regards to the standards used in thermoplastics processing technology. We argue that the cross-section structure of the sample obtained via FDM is the key factor in the fabrication of high-strength components and that the dimensions of the samples have a strong influence on the mechanical properties. Large cross-section samples, 4 × 10 mm2, with three perimeter layers and 50% infill, have lower mechanical strength than injection molded reference samples—less than 60% of the strength. However, if we reduce the cross-section dimensions down to 2 × 4 mm2, the samples will be more durable, reaching up to 110% of the tensile strength observed for the injection molded samples. In the case of large cross-section samples, strength increases with the number of contour layers, leading to an increase of up to 97% of the tensile strength value for 11 perimeter layer samples. The mechanical strength of the printed components can also be improved by using lower values of the thickness of the deposited layers.

scholarly journals Materials for Automotive Lightweighting

2019 ◽  
Vol 49 (1) ◽  
pp. 327-359 ◽  
Author(s):  
Alan Taub ◽  
Emmanuel De Moor ◽  
Alan Luo ◽  
David K. Matlock ◽  
John G. Speer ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Low Carbon Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
New Materials ◽  
Specific Strength ◽  
Advanced High Strength Steels ◽  
Strength And Stiffness ◽  
The Cost

Reducing the weight of automobiles is a major contributor to increased fuel economy. The baseline materials for vehicle construction, low-carbon steel and cast iron, are being replaced by materials with higher specific strength and stiffness: advanced high-strength steels, aluminum, magnesium, and polymer composites. The key challenge is to reduce the cost of manufacturing structures with these new materials. Maximizing the weight reduction requires optimized designs utilizing multimaterials in various forms. This use of mixed materials presents additional challenges in joining and preventing galvanic corrosion.

Microstructural Refinement in a Commercial Aluminum Alloy Processed by ECAP Using a Die Channel Angle of 110 Degrees

2015 ◽  
Vol 1114 ◽  
pp. 3-8
Author(s):  
Nicolae Şerban ◽  
Doina Răducanu ◽  
Nicolae Ghiban ◽  
Vasile Dănuţ Cojocaru
Keyword(s):  
Grain Refinement ◽  
Cross Section ◽  
High Strength ◽  
Secondary Phase ◽  
Coarse Grained ◽  
Metallographic Analysis ◽  
Second Phase ◽  
Channel Angle ◽  
Ambient Temperatures ◽  
Fine Grained

The properties of ultra-fine grained materials are superior to those of corresponding conventional coarse grained materials, being significantly improved as a result of grain refinement. Equal channel angular pressing (ECAP) is an efficient method for modifying the microstructure by refining grain size via severe plastic deformation (SPD) in producing ultra-fine grained materials (UFG) and nanomaterials (NM). The grain sizes produced by ECAP processing are typically in the submicrometer range and this leads to high strength at ambient temperatures. ECAP is performed by pressing test samples through a die containing two channels, equal in cross-section and intersecting at a certain angle. The billet experiences simple shear deformation at the intersection, without any precipitous change in the cross-section area because the die prevents lateral expansion and therefore the billet can be pressed more than once and it can be rotated around its pressing axis during subsequent passes. After ECAP significant grain refinement occurs together with dislocation strengthening, resulting in a considerable enhancement in the strength of the alloys. A commercial AlMgSi alloy (AA6063) was investigated in this study. The specimens were processed for a number of passes up to nine, using a die channel angle of 110°, applying the ECAP route BC. After ECAP, samples were cut from each specimen and prepared for metallographic analysis. The microstructure of the ECAP-ed and as-received material was investigated using optical (OLYMPUS – BX60M) and SEM microscopy (TESCAN VEGA II – XMU). It was determined that for the as-received material the microstructure shows a rough appearance, with large grains of dendritic or seaweed aspect and with a secondary phase at grain boundaries (continuous casting structure). For the ECAP processed samples, the microstructure shows a finished aspect, with refined, elongated grains, also with crumbled and uniformly distributed second phase particles after a typical ECAP texture.

Study on the Performance of the New High-Strength Steel-Encased Concrete Composite Beam (SCCB)

2013 ◽  
Vol 756-759 ◽  
pp. 161-165
Author(s):  
Qi Yin Shi ◽  
Chao Liu ◽  
Li Lin Cao ◽  
Zhen Wang
Keyword(s):  
Cross Section ◽  
High Strength Steel ◽  
High Strength Concrete ◽  
Composite Beam ◽  
High Performance ◽  
Bending Strength ◽  
Theoretical Study ◽  
High Strength ◽  
Simply Supported ◽  
Ordinary Steel

On the basis of the theoretical study and application of ordinary steel-encased concrete composite beam, this paper will focus on a new high-strength steel-encased concrete composite beam, and mainly studies high-performance steel Q420 and Q460, as well as high-strength concrete C60 and C80. Besides, an experimental study of 5 simply-supported beams is made, and the load-deflection curves of new SCCB are analyzed. The calculation formula of load which changes with depth of section and bending strength of the cross section is also analyzed. It is suggested that the calculated results announced should be identical with the experimental results.

Springback law of high-strength 21-6-9 stainless steel tube in numerical control bending under different process parameters

2015 ◽  
Vol 231 (10) ◽  
pp. 1783-1792 ◽  
Author(s):  
Jun Fang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Zhengjun Yao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Cross Section ◽  
Process Parameters ◽  
High Strength ◽  
Steel Tube ◽  
Numerical Control ◽  
Stainless Steel Tube ◽  
Outer Diameter ◽  
The Cross

In order to achieve the precision bending deformation, the effects of process parameters on springback behaviors should be clarified preliminarily. Taking the 21-6-9 high-strength stainless steel tube of 15.88 mm × 0.84 mm (outer diameter × wall thickness) as the objective, the multi-parameter sensitivity analysis and three-dimensional finite element numerical simulation are conducted to address the effects of process parameters on the springback behaviors in 21-6-9 high-strength stainless steel tube numerical control bending. The results show that (1) springback increases with the increasing of the clearance between tube and mandrel Cm, the friction coefficient between tube and mandrel fm, the friction coefficient between tube and bending die fb, or with the decreasing of the mandrel extension length e, while the springback first increases and then remains unchanged with the increasing of the clearance between tube and bending die Cb. (2) The sensitivity of springback radius to process parameters is larger than that of springback angle. And the sensitivity of springback to process parameters from high to low are e, Cb, Cm, fb and fm. (3) The variation rules of the cross section deformation after springback with different Cm, Cb, fm, fb and e are similar to that before springback. But under same process parameters, the relative difference of the most measurement section is more than 20% and some even more than 70% before and after springback, and a platform deforming characteristics of the cross section deformation is shown after springback.

Sign in / Sign up

Export Citation Format

Share Document