Journal Articles

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Subject: search.filters.subject.Tensile strength

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Now showing 1 - 10 of 203
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    Rotating bending fatigue tests were carried out on austempered ductile iron containing 1.5 wt% nickel and 0.3 wt% molybdenum. The ductile iron was austenitized at 900 or 1050 °C and then austempered at 280 or 400 °C for different lengths of time to obtain different microstructures. The fatigue strength was correlated with the amount of retained austenite and its carbon content, which were both determined by X-ray diffraction technique. While the tensile strength decreased with increasing retained austenite content, the fatigue strength was found to increase. Carbide precipitation was found to be detrimental to fatigue strength. Lower austenitizing temperature resulted in better fatigue strength. © 1994 Chapman & Hall.
    (Kluwer Academic Publishers, Effect of microstructure on the fatigue strength of an austempered ductile iron) Shanmugam, P.; Prasad Rao, P.; Rajendra Udupa, K.; Venkataraman, N.
    1994
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    Study of the properties of SCC with quarry dust
    (2009) Gowda, M.R.; Narasimhan, M.C.; Karisddappa; Rajeeva, S.V.
    Granite fines or rock dust is a by-product obtained during crushing of granite rocks and is also called quarry dust (QD). This paper deals with using quarry dust as an alternative to fine aggregate (FA) in SCC and reports the strength behaviour and hardened properties of such SCCs. Although in normal concretes, introducing QD increases the water demand, in SCC, it has been successfully used for increasing the deformability and passing ability of fresh concrete. Also, it was noted that by increasing the pouring heights of an SCC, the compressive strength and splitting tensile strength of concrete were unaffected.
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    Mechanical and acoustic properties of areca fiber reinforced phenol formaldehyde composites
    (2010) Mohan Kumar, G.C.M.
    In this paper, mechanical and acoustic properties of natural areca fiber reinforced phenol formaldehyde composite are studied. Areca fiber composites were prepared using phenol formaldehyde with randomly distributed fibers. Strength of the composite is determined and other tests like adhesion tensile test, moisture absorption test, and biodegradable were also carried out. Acoustic tests are carried out to measure the sound transmission loss (STL) of the cured composite and compared with wood based particle board. The results show that the fully developed material has higher STL for frequencies up to 3 kHz compared to wood-based particle boards.
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    Studies on concrete cylinders subjected to elevated temperatures
    (2010) Babu Narayan, K.S.; Anil Kumar, G.; Chandrakala, C.; Shashikumar, H.M.; Venkataramana, K.; Yaragal, S.C.; Chinnagiri Gowda, H.C.; Reddy, G.R.; Sharma, A.
    Concrete is a poor conductor of heat, but can suffer considerable damage when exposed to fire. Concrete in structures is likely to be exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. Unraveling the heating history of concrete is important to forensic research or to determine whether a fire exposed concrete structures and its components are still structurally sound or not. Assessment of fire damage concrete structures usually starts with visual observation of color change, cracking and spalling. On heating, a change in color from normal to pink is often observed and this is useful since it coincides with the onset of significant loss of concrete strength. This work reports the characteristics of concrete at elevated temperatures. Popular normal strength grades (M20, M25, M30, M35, M40 and M45) produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm diameter and 300mm height cylinders) to obtain more meaningful and realistic data. In the preliminary phase 150 mm diameter and 300mm height cylinders were cast, cured and tested by destructive method for gathering data on strength characteristics. Later these test samples were subjected to elevated temperatures ranging from 100°C to 800°C, in steps of 100°C with a retention period of 2 hours. After exposure, weight losses were determined and then again destructive tests were conducted to estimate the residual split tensile strength. Test results indicated that weight and strength significantly reduces with an increase in temperature. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Correlation between Petrographical and engineering properties of Ilkal granites, Karnataka
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Venkat Reddy, D.; Santosh, H.G.; Priyanka, K.
    Granitic rocks show a variety of engineering properties that may affect quarrying operations, slope stability, mining and the use of rock as a structural as well as architectural material. In present investigation, correlation analysis is carried out for experimental results to study the influence of mineralogical and textural characteristics on physical and strength properties using SPSS software. A variety of granitic rock samples from different parts of Ilkal were subjected to study petrographical and then same samples were tested to determine the specific gravity, bulk and dry density, water absorption, porosity, P-wave velocity, rebound hardness, point load strength index, uniaxial compressive strength and tensile strength. The study revealed that a petrographical characteristic like grain size, mineral composition and the bonding between each mineral of granitic rocks plays a major role in contributing the strength parameters. © 2011 Cafet-Innova Technical Society. All rights reserved.
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    Effect of mushy state rolling on age-hardening and tensile behavior of Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite
    (Elsevier Ltd, 2011) Siddhalingeshwar, I.G.; Herbert, M.A.; Chakraborty, M.; Mitra, R.
    The effect of mushy state rolling on aging kinetics of stir-cast Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite and their tensile behavior in solution-treated (495°C) or differently aged (170°C) conditions, has been investigated. As-cast or pre-hot rolled alloy and composite samples were subjected to single or multiple mushy state roll passes to 5% thickness reduction at temperatures for 20% liquid content. Peak-aging times of mushy state rolled composite matrices have been found as ?7.5-10% of that of as-cast alloy. Such enhancement in aging kinetics is attributed to homogeneity in Cu atom distribution as well as increase in matrix dislocation density due to thermal expansion coefficient mismatch between Al and TiB2, matrix grain refinement and particle redistribution, achieved by mushy state rolling. Uniform precipitate distribution in mushy state rolled composite matrices leads to greater peak-age microhardness with higher yield and ultimate tensile strengths than those in as-cast alloy and composite. © 2010 Elsevier B.V.
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    Characteristics of normal strength concrete with and without chemical admixtures at elevated temperatures
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Yaragal, S.C.; Warad, S.A.; Babu Narayan, K.S.; Venkataramana, K.
    Fire is one of the most destructive powers to which a building structure can be subjected. Behavior of concrete when exposed to fire in cases like nuclear plants, cooling towers or any accidental fire in industrial buildings, is a serious concern, on the strength retention property of concrete. This work reports strength retention studies on compressive and split tensile strength of normal concrete with and without the chemical admixture (Reobuild 918, BASF make) at elevated temperatures. Concrete cubes of size 100 mm have been cast as per prior mix design for M30 grade of concrete, 28 days water cured and tested by destructive method for strength before exposure. Later these specimen were subjected to elevated temperatures of 200°C, 400°C, 600°C and 800°C with a retention period of 2 hours and were allowed cool within the furnace to reach ambient temperature. Later their appearance, colour and cracks were observed and also weight losses were determined. Further, destructive tests were conducted to estimate residual compressive and residual split tensile strengths and prediction equations are proposed to ascertain splitting tensile strengths from compressive strengths. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Studies on Uniaxial compressive strength of laterite masonry prisms
    (2011) Unnikrishnan, S.; Narasimhan, M.C.; Venkataramana, K.
    Laterite is a well known conventional building material in Asian countries. In spite of its large popularity in construction, a systematic characterization of this material, as a building block, has not been seriously attempted so far. The strength and elastic properties of laterite masonry are influenced by the individual properties of the laterite blocks and the mortar. In the present study, characterization of the laterite block and the mortar and compressive strength of laterite masonry prisms have been investigated using detailed laboratory experiments and numerical analysis. The experimental results, related to the compressive strength and stress-strain characteristics of laterite and mortar and compressive strength of laterite masonry prisms are presented. Finite element analysis of laterite masonry prism has also been carried out. The studies have shown that the modulus of elasticity of laterite blocks tested is less than that of mortar used in making the laterite masonry. Further, the laterite masonry prisms have been observed to have failed by bond failure and subsequent splitting of laterite blocks. Also, increase in thickness of mortar joint gives rise to a decrease in laterite tensile stresses in mortar joint leading to higher prism strengths, if bond remains intact. © 2011 CAFET-INNOVA technical society. All right reserved.
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    The LEO Archipelago: A system of earth-rings for communications, mass-transport to space, solar power, and control of global warming
    (2011) Meulenberg, A.; Karthik Balaji, P.S.
    Mans quest to get into space is hindered by major problems (e.g., system-development and capital costs, expense of putting mass into orbit, trapped-radiation belts, and environmental impact of a large increase in rocket launches). A multi-purpose low-earth-orbit system of rings circling the earth the LEO ARCHIPELAGOTM is proposed as a means of solving or bypassing many of them. A fiber-optic ring about the earth would be an initial testing and developmental stage for the Ring Systems, while providing cash-flow through a LEO-based, high-band-width, world-wide communication system. A low-earth-orbit-based space-elevator system, Sling-on-a-RingTM, is proposed as the crucial developmental stage of the LEO Archipelago. Being a LEO-based heavy-mass lifter, rather than earth- or GEO-based, it is much less massive and therefore less costly than other proposed space-elevators. With the advent of lower-cost, higher-mass transport to orbit, the options for further space development (e.g., space solar power, radiation, and space-debris dampers, sun shades, and permanent LEO habitation) are greatly expanded. This paper provides an update of the Sling-on-a-Ring concept in terms of new materials, potential applications, and trade-offs associated with an earlier model. The impact of Colossal Carbon Tubes, CCT, a new material with high tensile strength, extremely-low density, and other favorable properties, and other new technologies (e.g., solar-powered lasers, power beaming to near-space and earth, and thermal-control systems) on the development of associated LEO-Ring systems is also explored. The materials effect on the timeline for the system development indicates the feasibility of near-term implementation of the system (possibly within the decade). The Sling-on-a-Ring can provide a less-expensive, environment-friendly mode of access to space. This would pave the way (via eventual operation at >1000 t per day by 2050) for large scale development of space-based technologies. © 2011 Elsevier Ltd. All rights reserved.