• International Journal of Concrete Structures and Materials
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• v.10 no.3
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• pp.373-381
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• 2016

As part of this study, has been developed a numerical method which allows to establish abacuses connecting the normal force with bending moment for a circular section and therefore to predict the rupture of this type of section. This may be for reinforced concrete (traditional steel) or concrete reinforced with steel fibers. The numerical simulation was performed in nonlinear elasticity up to exhaustion of the bearing capacity of the section. The rupture modes considered occur by plasticization of the steel or rupture of the concrete (under compressive stresses or tensile stresses). Regarding the fiber-reinforced concrete, the rupture occurs, usually, by tearing of the fibers. The behavior laws of the different materials (concrete and steel) correspond to the real behavior. The influence of several parameters was investigated, namely; diameter of the section, concrete strength, type of steel, percentage of reinforcement and contribution of concrete in tension between two successive cracks of bending. A comparison was made with the behavior of a section considering the conventional diagrams of materials; provided by the BAEL rules. A second comparative study was performed for fibers reinforced section.

• Fashion & Textile Research Journal
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• v.11 no.3
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• pp.469-473
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• 2009

Recently, eco-friendly processing has been focused in the textile industry in order to reduce environmental pollutions. Applications of enzyme technology to the textile industry are an example of more environmentally compatible processes. However, there is not enough quantity of referring to denim fabric subjected to enzymatic treatment. In this study, depending on pH, temperature, cellulase concentration, and treatment time, the weight loss of denim fabrics was examined. Characteristics of enzyme-treated fabrics were measured by tearing strength, stiffness, and K/S values. The effect of a non-ionic surfactant (Triton X-100) on characteristics of the enzyme-treated fabrics was evaluated. The cellulase treatment condition on the cotton fabric were optimized to pH 6.0, $50^{\circ}C$, 1%(o.w.f.), and 60minutes. Characteristics of denim fabrics by cellulase treatment in the presence of Triton X-100 did not improve because Triton-X inhibited the activity of enzyme.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.11a
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• pp.71-78
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• 2004

Most of member parts have experienced severe springback problems because of their open shape Now it becomes imperative to develop an effective method, which can resolve these problems. However, there remain several obstacles to get accurate estimation of shape error. In analysis, we have to analyze the total process including forming, trimming and flanging. Furthermore, it is another challenge to compare the computed result with the real shape. In this study we developed an analysis program for the springback analysis. We could achive a big enhancement in computation time in springback analysis by using latest equation solving technique and could get a more robust solution conversence by contination method. We have approached this problem in two steps. In the first step, we analyzed forming stage to solve tearing and wrinkling problems. In the second step, we have analyzed full process and have done springback analysis with the same boundary condition as field measuring conditions. We have investigated the accuracy of springback analysis in terms of gap and flush used for insfection of real autobody panels. We found good and effective agreement with the observed results.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4647-4658
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• 2023

In this paper, elastic-plastic fracture mechanics analysis is performed to determine the critical crack sizes of the multipurpose canister (MPC) manufactured using austenitic stainless steel under dynamic loading conditions that simulate drop accidents. Firstly, dynamic finite element (FE) analysis is performed using Abaqus v.2018 with the KORAD (Korea Radioactive Waste Agency)-21 model under two drop accident conditions. Through the FE analysis, critical locations and through-thickness stress distributions in the MPC are identified, where the maximum plastic strain occurs during impact loadings. Then, the evaluation using the failure assessment diagram (FAD) is performed by postulating an external surface crack at the critical location to determine the critical crack depth. It is found that, for the drop cases considered in this paper, the principal failure mechanism for the circumferential surface crack is found to be the plastic collapse due to dominant high bending axial stress in the thickness. For axial cracks, the plastic collapse is also the dominant failure mechanism due to high membrane hoop stress, followed by the ductile tearing analysis. When incorporating the strain rate effect on yield strength and fracture toughness, the critical crack depth increases from 10 to 20%.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.231-238
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• 2017

There are many kinds of elements and processes for the development of high quality bedding products like fiber, high-temperature heat treatment, dyeing process, tenter drying with softening agent and multiple final finishing. Especially we examined the mechanical characteristic properties of fabrics according to different yarn types. The critical physical properties of the yarn consisting the pile knitted fabrics were obtained for the development of the hi-grade bedding items. The material property and the exhaustion behaviour of the developed pile knitted fabrics composing of different yarns were measured and observed. The physical properties of the developed fabric were evaluated through the material property analysis of the yarn, the physical nature of the pile knitted fabrics and the data of the exhaustion performance; tensile strength, tensile elongation, tearing strength, cross section of yarn types, dyeing properties etc. And then high-class of bedding items were knitted using the double raschel machine to make the pile knitted fabrics.

• Elastomers and Composites
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• v.8 no.1
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• pp.33-51
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• 1973

We have studied the blending effects of Diene NF 35 R and Alfin 1530 at various blending ratios, 100/0, 70/30, 50/50, 30/70, 0/100, and of carbon black HAF-HS and ISAF-HS at various compounding ratios of 45 PHR, 55 PHR, 65 PHR, for tyre tread rubber. As the results, it was found that; 1. For tyre tread rubber, as the blending ratio, AR 1530/Diene NF 35R, indicated 70/30, the physical properties we examined were most excellent. 2. Excellent result was obtained in the case of carbon black compounding ratio of 55 PHR. The compounding of ISAF-HS made better result than that of HAF-HS for tensile strength, but the compounding of HAF-HS made better result than that of ISAF-HS for tearing strength and best result for abrasion quantity. 3. Heat buildup obtained from compounding carbon black HAF-HS indicated low temperature than that from compounding carbon black HAP-HS. As the compounding amount of carbon black increased, and as the blending amount of AR 1530 decreased, the heat buildup increased. 4. Carbon black was more efficient to AR 1630 than io Diene NF 35 R. 5. In the physical properties, mooney viscosity and mooney scorch time, as the compounding amount of carbon black increased, the values of mooney viscosity increased, but that of mooney scorch time had a max. point at the compoundiug amount of carbon black, 55 PHR.

• Elastomers and Composites
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• v.34 no.4
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• pp.341-349
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• 1999

In this study, heat and crack resistance of natural rubber (NR) compounds was evaluated. To prevent the effects of the crosslinking system, a conventional vulcanization system was selected, where the accelerator/sulfur ratio was fixed to 0.25. Vulcanizates containing phenylenediamine showed high tensile strength and tear strength compared to other vulcanizates because phenylenediamine can cause additional crosslinking and high dispersion In the vulcanizates. In the pure shear test, vulcanizates containing phenylenediamine showed an excellent tearing energy which was due to the irregular crack path, and showed excellent heat and crack resistance which was also due to the good dispersity of antioxidant and additional crosslinks in the rubbber vulcanizates.

• KSBB Journal
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• v.11 no.6
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• pp.718-725
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• 1996

Old newsprint was deinked with endoglucanase, exoglucanase and their various compositions from Trichoderma viride. The yield decreased with an increase in enzyme concentration. Especially, it was the lowest in the treatment of endo-exo mixture(1:1). It may be regarded as a synergistic actions of the cellulase components. The brightness was the highest in pulp deinked with endo-exo mixture(1:1). Maximum brightness was observed when 0.5mg/mL of the endo-exo mixture was used. The physical strength increased with increasing concentration in exoglucanase. But, it decrease with increasing concentration in endoglucanse and endo-exo mixture(1:1). Also, we investigated the yield, brightness and physical strength of endoglucanase in combination with exoclucanase(12:1, 8:1, 4:l, 1:1, 1:4, 1:8, 1:12). Maximal deinking conditions, obtained at a specific optimal ratio of endoglucanase to exoglucanse are as follow ; 12:1 for yield, 12:1 for brightness, 4:1 for tensile strength, 12:1 for bursting strength, and 8:1 for tearing strength. These results indicated that the deinking depended largely upon the action of endoglucanase. Exoglucanase was occupying more than 60% of the total crude cellulase contents. Therefore, the most effective deinking must repress the action of exoglucanase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.9-20
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• 2019

The number of natural disasters in Korea, such as earthquakes, is increasing. As a result, there is growing need for temporary residences or shelters for disaster conditions. The aim of this study was to produce post-disaster refugees housing differentiated from existing shelters using lightweight composite panels. To accomplish this, the structural performance of lightweight composite panels was validated, and an in-plane shear strength test was conducted according to the ASTM E72 criteria among the performance test methods for panels. As a result of the experiment, the maximum load for each specimen under an in-plane shear load was determined. All the experiments ended with the tear of the panel's skin section. The initial stiffness of the specimens was consistent with that predicted by the calculations. On the other hand, local crushing and tearing, as well as the characteristics of the panel, resulted in a decrease in stiffness and final failure. Specimens with an opening showed a difference in stiffness and strength from the basic experiment. The maximum load and the effective area were found to be proportional. Through this process, the allowable shear stress of the specimens was calculated and the average allowable shear stress was determined. The average ultimate shear stress of the lightweight composite panels was found to be $0.047N/mm^2$, which provides a criterion of judgement that could be used to expect the allowable load of lightweight composite panels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.39-48
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• 1978

1) The decrease in strength of Raschel twines at Raschel joints is regarded to be due mainly to the frictional force between yarns and the unbalanced tensile distribution by the deformation of the joints. The rate of the decrease is about $13\%$ in lengthwise pull and 22 to $26\%$ in breadthwise pull. 2) The 3-course joint is less in deformation and stronger than the 2-course joint in all cases of pulls. 3) The variation of Raschel joint strength $T_R$ with the angle $\varphi$ between the adjacent bars is expressed as $T_R=T_{R0}-k\varphi$ where $T_{R0}$ is the strength at $\varphi=0^{\circ}$ and K is a constant. 4) The tensile strength ${\sigma}R$ and tile breaking energy $E_R$ of Raschel netting are given by $${\sigma}R=KN\;or\;${\sigma}R=T_RN$$ and $$E_R=AN$$ respectively, where N is the number of meshes at the pulling side, and K and A are constants. But the breaking energy of the netting is almost constant independent of tile variation of N. 5) The Raschel netting with some bars cut already breaks from tile joints of the bars next to the cut bars and its tensile strength, breaking energy, and breaking elongation decrease largily even if only one bar is in already cut state. 6) The tearing strength of Raschel netting is almost equal to the tensile strength of its single joint pulled by two bars. 7) The twisted joint is much more excellent in strength than the knot or the Raschel joint. The knot strength is 69 to $76\%$, and the Raschel joint strength is 71 to $74\%$ in lengthwise pull and 62 to $67\%$ in breadthwise pull, respectively, of the twisted joint strength.