Papers by Keyword: Mass Loss

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Authors: Gilbert Rainer Gillich, Zeno Iosif Praisach, Daniel Bobos, Cornel Hatiegan
Abstract: Corrosion as material destruction affects the safety of structures, leading to more serious consequences than the simple loss of a mass. The effect of corrosion on the dynamic behaviour of structures act in two ways: the loss of mass increases the natural frequencies, opposite to the effect of stiffness loss. This paper present the results of researches made to extend the mathematical relation presenting the influence of damage location and severity on the natural frequency changes, by adding the effect mass loss. Therefore we modeled the beam once with the discontinuity and loss of mass, afterwards the damaged segment is replaced by an intact one but having the mass similar to that of the damaged segment. This permitted to plot frequency shift curves for both cases and to contrive the relations defining that curves. Finally a relation summarizing the both effects was contrived; it was confirmed both by numerical simulations and experiments.
Authors: Said Larbi, Said Djebali, Ali Bilek
Abstract: The aim of the present work is the investigation of the influence of graphite powder addition to an unsaturated polyester type polymer (32% styrene content in mass) on the mechanical and tribological properties. For this purpose, we conducted bending tests and wear tests with a combination of four loads and three speeds for three different compositions (0, 1 and 2% graphite). The wear tests are carried out on a dry type pin on disk tribometer. The disk is made of quenched and annealed C48 steel (540 Hv hardness). Before the rubbing process, the discs are subjected to polishing in order to obtain approximately the same initial surface roughness. The results show that the addition of graphite powder improves the tribological properties; a noticeable decrease of the coefficient of friction, the mass loss and the wear rate are achieved with the increase of the graphite powder percentage for all sliding speeds and loads. A 2% graphite content causes a drop of the friction coefficient from 0.4 to 0.2. The results of bending tests showed a significant decrease of the stress and strain at failure and a slight increase in Young's modulus. In addition, for the three compositions, the results show a clear preponderance of the influence of the load on the tribological properties.
Authors: Yuki Nakamura, Shoichiro Yoshihara, Bryan J. Mac Donald, Emmet Galvin
Abstract: In this study, the influence of mechanical and electrochemical phenomena on the corrosion behavior of SUS304 stainless steel bolt was investigated. A corrosion test bench was developed and the influence of the initial axial strain, the corrosion type and the corrosion potential on the nature and kinetics of the corrosion processes was examined. It was carried out that the corrosion experiment of different the initial axial force and the corrosion potential. In addition, we obtain the stress distribution by the finite element analysis (FEA), after that we compared the stress distribution to the experimental results of the corrosion distribution.
Authors: Quan Lin Niu, Nai Qian Feng
Abstract: Corrosion resistance coefficient of mortars incorporating different mineral admixtures were tested according to GB2420, and the expansion ratio of mortar bar immersed in 5% Na2SO4 solution was measured according to ASTM C1012. It is shown that all the mineral admixtures, including ground granulated blast furnace slag (SL) fly ash (FA), natural zeolite (NZ) and metakaolin (MK) were effective in decreasing the 15-week expansion and increasing the corrosion resistance coefficient of the specimens immersed in Na2SO4 solution as well.
Authors: Hanan A. El Nouhy
Abstract: This research investigates the influence of high temperature on the properties of bricks containing non-ground granulated blast-furnace slag (GBFS) as fine aggregate replacement. Replacement percentages were 0%, 25% and 50% by dry weight of fine aggregates. The manufactured bricks were exposed to 200°С, 400°С, 600°С, and 800°С for a constant duration of two hours after 28 days of curing. Tests were conducted according to both Egyptian Standard Specifications (ESS) and American Society for Testing and Materials (ASTM) in order to determine compressive strength, absorption percentage, oven-dry weight, and ultrasound pulse velocity. Also, loss in weight was performed. Compressive strength limit regarding load-bearing units was met by mix 1 at all tested temperatures. Mixes 2 and 3, resulted in compressive strength that satisfied the requirement for load-bearing units at temperatures ranging from room temperature to 600°С.Compressive strength obtained regarding mixes 2 and 3 met the requirements of non-load bearing units at 800°С. The control mix resulted in normal weight bricks when tested at the various temperatures till 600°С. At 800°С, mixes 2 and 3 yielded light weight and medium weight bricks, respectively. There was a significant reduction in mass when comparing the mass at 800°С with the corresponding mass at room temperature concerning the three mixes. Results showed that it is feasible to partially replace fine aggregate with GBFS even when bricks are subjected to elevated temperature.
Authors: Suo Xian Yuan, Hui Ding, Wan Shan Wang
Abstract: The grinding process of aluminum alloy is introduced in the paper and carried out experiment. The material is removed from the workpiece by fixed abrasives and scratching the surface to be finished in grinding process. In order to increase machining accuracy and efficiency, it is necessary to analyze the machining parameters of grinding process. The emphasis is the effect of machining parameters on roughness of surface and mass loss of workpiece by a set of experiments in this paper.
Authors: Xiao Chun Fan, Di Wu, Hu Chen
Abstract: Basalt fiber reinforced concrete has excellent basic mechanical properties. It has become a hot topic of engineering studies. Based on the freeze-thaw resistance of durability indices, through the comparative experiment on the dynamic elastic modulus and mass loss of plain concrete and basalt fiber reinforced concrete in the freeze-thaw cycles, this paper had discussed the impact of basalt fiber on the freeze-thaw resistance of concrete, and have considered whether the specimens were mixed with fly ash. The results showed that basalt fibers can improve the freeze-thaw resistance of concrete specimens significantly. After 100 freeze-thaw cycles, the dynamic elastic modulus of basalt fiber reinforced concrete specimens was 1.47 times as much as that of plain concrete specimens, and mass loss of basalt fiber reinforced concrete specimens was 0.64 times as much as that of plain concrete specimens. Fly ash had an influence on the freeze-thaw resistance of basalt fiber reinforced concrete. In engineering applications, the mixing amount of fly ash should be taken into consideration. This research had a certain reference value on the engineering applications of basalt fiber reinforced concrete.
Authors: Zhi Gang Yin, Jun Feng, Shu You Huang, Bing Fang Zhao
Abstract: The frost resistance of low strength concrete is researched. In order to evaluate the effect of different content of silica fume on frost resistance,the quality of the cement 6%, 9%, 12% silica fume are respectively added into concrete. Freezing-thawing test results show that: the silica fume concrete has good frost resistance. Content of silica fume on concrete is not almost effect to quality loss rate. In 0-250 times of freezing-thawing cycle range, it is smaller that relative dynamic elastic modulus change rate. Relative dynamic elastic modulus of ordinary concrete decreases rapidly after 250 times of freezing-thawing cycle while dynamic elastic modulus decrease rate of the silica fume concrete tends to slow. The freezing -thawing cycles up to 350 times, silica fume concrete relative dynamic elastic modulus is 1.5 times that of ordinary concrete that show the silica fume concrete frost resistance is better than that of ordinary concrete.
Authors: Xiao Yan Zhang, Xin Xin Ding, Shun Bo Zhao, Zhan Fang Ge
Abstract: Experiments were conducted to study the effects of source rock state and stone powder on freeze-thaw resistance of concrete with proto-machine-made sand, the strength grade of concrete was C50, the source rock states were gravel and crushed stone, the contents of stone powder in sand were 5%, 9% and 13% respectively. The values of relative dynamic elastic modulus and mass of concrete at different freeze-thaw cycle times were measured, the reduction of relative dynamic elastic modulus and mass loss were calculated to evaluate the freeze-thaw resistance of concrete. The results show that freeze-thaw resistances are controlled by the reduction of relative dynamic elastic modulus of concrete, which are good of concrete with proto-machine-made sand of gravel and crushed stone, and increases with the increasing content of stone powder in sand made of gravel. The reasons leading to difference of freeze-thaw resistance of concrete with sand made of gravel and crushed stone are discussed.
Authors: Ming Yi Chen, Richard Yuen, Jian Wang
Abstract: In this paper, a report is given on an experimental study of the combustion characteristics of six bundle lithium-ion batteries in a calorimeter. Several parameters including mass loss, heat release rate, surface temperature and heat flux distribution were measured to evaluate the hazards. The experimental results show that the lithium-ion batteries undergo fierce combustion processes. The total mass loss of six lithium-ion batteries fire is 67.8g, and the effective heat of the fire is 7.06 kJ/g. The highest temperature of the batteries fire is 816.9 °C and the maximum heat flux is 0.68 kW/m2.The results provide scientific basis for the development of fire protection measures during the usage, storage and distribution of primary lithium batteries.
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