Bending strength of shallow glued-laminated beams of a uniform grade

Author(s):  
Catherine M. Marx ◽  
Russell C. Moody

Durian timber grows well in the Gunungpati area, although its use is still limited to the needs of light construction. Lamination (glulam) is a combination of one or more kinds of materials and the materials are made into relatively thin layers glued together to form a larger dimension. Timber engineering experiment was conducted by creating a laminated beam made of Durian and coconut timber, with a composition of coconut - Durian – coconut. The purpose of this study was to determine the bending strength of a composition of coconut – durian – coconut laminated beam in strengthening the weak side of the durian timber. Coconut timber was used to reinforce durian timber because the weight of coconut timber is relatively larger compared to Durian timber. Durian laminated beam with coconut timber reinforcement on the top and bottom can be used as an alternative material to improve the bending strength durian timber. Lamination technology was able to increase the bending strength of Durian timber with laminated beams by 12.6% from the average bending strength of 36.68 MPa durian timber, laminated beams into bending strength of 41.30 MPa.


2016 ◽  
Vol 18 (1) ◽  
pp. 39-46
Author(s):  
Sri Handayani

Wood Sengon (Sengon) is a type of timber that can quickly grow, accessible but its use as a construction material has not been optimized. The technology used to support the wood as a construction material is a laminate. Engineering experiments was done by making laminated beams of wood Sengon and wood coconut. The purpose of this study is to determine how much the increase in flexural strength for laminated wood Sengon beams and wood Coconut beams as a replacement of structural beam with a variety of adhesive and timber placement. The method used is an experimental method for flexural strength testing of laminated beams. The results showed an average flexural strength of the maximum obtained in laminated beams with variations EP-S (adhesive epoxy glue and placement position in the wood Sengon) amounted to 679 350 kg / cm2. An increase in the strength of 254 025 kg / cm2 (59.72%) are from wood Sengon bending strength 425 325 kg / cm2 (probe grade IV) to 679 350 kg / cm2 (strong class III). The use of technology should pay attention to the position of the bearing laminated wood. Wood with strong higher class should be put on the outside position to provide reinforcement for the wood with a powerful low grade placed in the position.Kayu Sengon (Sengon) termasuk dalam jenis kayu yang dapat dengan cepat tumbuh, mudah di dapat tetapi penggunaannya sebagai bahan konstruksi belum optimal. Teknologi yang digunakan guna mendukung kayu sebagai bahan konstruksi adalah dengan laminasi. Rekayasa eksperimen dilakukan dengan membuat balok laminasi dari kayu Sengon dan kayu Kelapa. Tujuan penelitian ini adalah untuk mengetahui seberapa besar peningkatan kuat lentur balok kayu dengan laminasi Sengon dan Kelapa sebagai pengganti balok struktur dengan variasi bahan perekat dan perletakan kayu. Metode penelitian yang digunakan adalah metode eksperimen untuk pengujian kuat lentur balok laminasi. Hasil penelitian menunjukkan kuat lentur rata-rata maksimum diperoleh pada balok laminasi dengan variasi EP-S (perekat lem epoksi dan perletakan posisi kayu Sengon didalam) sebesar 679.350 kg/cm2. Terjadi peningkatan kekuatan sebesar 254.025 kg/cm2 (59.72%) yaitu dari kuat lentur kayu Sengon 425.325 kg/cm2 (kelas kuar IV) menjadi 679.350 kg/cm2(kelas kuat III). Penggunaan teknologi laminasi hendaknya memperhatikan posisi perletakan kayu. Kayu dengan klas kuat lebih tinggi diletakkan pada posisi luar untuk memberikan perkuatan pada kayu dengan kelas kuat rendah yang terletak pada posisi dalam.


2001 ◽  
Vol 14 (6) ◽  
pp. 499-522 ◽  
Author(s):  
Zheng-Ming Huang ◽  
X. C. Teng ◽  
S. Ramakrishna

The bending behavior of laminated beams reinforced with differently arranged plain-weft knitted fabrics has been investigated in this paper. Experiments were carried out to measure the bending stiffness and strength of six layers knitted fabric rein-forced epoxy composite laminates under 3-point bending. The laminate lay-ups of [0/0/0/0/0/0], [90/90/90/90/90/90] and [0/-45/45/45/-45/0] have been taken into account, where 0 denotes that the fabric wale direction is arranged along the beam axial direction. A simulation procedure is presented to analyze the bending property of the laminated beams based on the bridging micromechanics model and the classical lamination theory. It has been found that the use of a stress failure criterion only is no longer enough for estimating the ultimate bending strength of the laminate. An additional critical deflection condition is also required. By using only the constituent properties, which were measured using bulk material specimens independently, and the fabric knitting and lay-up parameters, the predicted stiffness and strength agree favorably with the experimental data.


The article presents the study of processes of structure formation of cement stone and products of hardening of organic-mineral compositions with fibrous filler (shavings) by the electronic scanning microscopy method. It is established that the additive-free cement stone at the age of 28 days has a dense and homogeneous structure, consists of calcium hydro-silicates, Portlandite and calcite - newgrowths characteristic for cement systems. Cellulose fibers, which make up the bulk of the substance of shavings, are sufficiently active, which determines the high adhesion of the hydration products of the cement binder to their surface. It is shown that the introduction of shavings into the organo-mineral composition leads to inhibition of cement hydration processes. Organo-mineral compositions with different shavings content (two compositions) were analyzed. The first composition is characterized by a fairly dense structure, the cement stone consists of globular nanoscale nuclei of hydrosilicates, Portlandite and calcite. The second composition has a loose porous structure, cement stone consists of non-hydrated cement grains, newgrowths are represented by calcite and vaterite. The structure of the contact zone "osprey fiber-cement stone" in the organo-mineral composition of the first composition indicates a good adhesion of the filler surface with the phases of hydrated cement. The use of shavings as a fibrous filler (the first composition) increases the tensile and bending strength, as well as the wear resistance of organo-mineral compositions. The data obtained by scanning electron microscopy are confirmed by the results of studying the processes of structure formation of cement stone by quantitative x-ray phase analysis.


2019 ◽  
Vol 13 (3) ◽  
pp. 5242-5258
Author(s):  
R. Ravivarman ◽  
K. Palaniradja ◽  
R. Prabhu Sekar

As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance than the standard drive.


2018 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
AMIR SYAFIQ SAMSUDIN ◽  
MOHD HISBANY MOHD HASHIM ◽  
SITI HAWA HAMZAH ◽  
AFIDAH ABU BAKAR

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.


1994 ◽  
Vol 43 (489) ◽  
pp. 599-605 ◽  
Author(s):  
Akira YAMAKAWA ◽  
Takehisa YAMAMOTO ◽  
Tomoyuki AWAZU ◽  
Kenji MATSUNUMA ◽  
Takao NISHIOKA

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.


2020 ◽  
Vol 2020 (10) ◽  
pp. 8-21
Author(s):  
A. G. Kolmakov ◽  
◽  
I. O. Bannykh ◽  
V. I. Antipov ◽  
L. V. Vinogradov ◽  
...  

he basic ideas about the process of introducing cores into protective barriers and the most common core patterns and their location in conventional and sub-caliber small arms bullets are discussed. The materials used for manufacture of cores are analyzed. It is concluded that for mass bullets of increased armor penetration the most rational choice can be considered the use of high-carbon low-alloy steels of a new generation with a natural composite structure and hardness of up to 70 HRC. For specialized armor-piercing bullets, cores made from promising economically-alloyed high-speed steels characterized by a high complex of «hardness—bending strength» are better alternative than ones made of hard alloys or tungsten alloys.


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