• 한국축산식품학회지
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• 제42권2호
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• pp.332-340
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• 2022

The objective of this study was to determine the optimal cooking time by considering the cooking loss, shear force, and off-odor reduction of pork large intestines. Commercial pork large intestines were purchased, quartered perpendicularly, and cooked in boiling water for 40, 120, 180, and 240 min. Cooking loss of the samples increased after 240 min of cooking (10.92, p<0.05) while shear force value was lower at 240 min (4.45) compared to that at other cooking times (p<0.001). The amount of major volatile organic compounds showed a decreasing trend with increasing cooking time. In particular, the amount of methyl pentanoate (17,528.71) and methyl isobutyrate (812.51), compounds with a relatively low odor threshold, decreased significantly after 120 min of cooking and no change was observed thereafter (p<0.05). In addition, the amount of 2-pentanol (3,785.65) and 1-propanol (622.26), possibly produced by lipid oxidation, significantly decreased at the same cooking time (p<0.001). In the principal component analysis, only the 40 min cooking time was significantly different from other cooking time by high amounts of 1-propanol, 2-pentanol, and methyl isobutyrate. In conclusion, in the present study, the optimal cooking time for pork large intestines was 120 min in terms of off-odor reduction, cooking loss, and shear force.

• 대한토목학회논문집
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• 제35권1호
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• pp.85-92
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• 2015

횡방향 철근이 없는 RC와 PSC 보에서 축방향 인장력은 전단강도를 감소시키고, 축압축력은 전단저항력을 증가시킨다는 것은 잘 알려진 사실이다. 그러나 축력이 전단에 얼마만큼 영향을 미치고, 전단 저항성능에 어떠한 영향을 주는가에 대한 이해가 부족한 현실이다. 횡방향 보강철근이 없는 부재가 큰 압축력과 전단력을 받으면 첫 번째 경사균열이 일어나면서 그대로 취성파괴가 발생하기 때문에 상당히 보수적 관점을 유지하고 있다. 이런 배경에서 ACI의 복부전단강도는 경사균열각 ${\theta}$를 $45^{\circ}$로 하는 트러스모델을 사용하여 스터럽의 수직력과 축력효과를 반영하고 있다. 본 연구는 파괴역학을 근간으로 한 비선형 유한요소해석 프로그램 ATENA-2D (Cervenka, 2000)를 사용하여 철근콘크리트 보의 축력작용에 따른 검증을 수행한 것이다.

• Steel and Composite Structures
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• 제48권2호
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• pp.131-143
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• 2023

The CFRP bar was used to achieve more ductile and durable headed-stud shear connectors in composite components. Three series of push-out tests were firstly conducted, including specimens reinforced with pure steel fibers, steel and CFRP bars. The distributed stress was measured by the commercial PPP-BOTDA (Pre-Pump-Pulse Brillouin optical time domain analysis) optical fiber sensor with high spatial resolution. A series of numerical analyses using non-linear FE models were also made to study the shear force transfer mechanism and crack response based on the test results. Test results show that the CFRP bar increases the shear strength and stiffness of the large diameter headed-stud shear connection, and it has equivalent reinforcing effects on the stud shear capacity as the commonly used steel bar. The embedded CFRP bar can also largely improve the shear force transfer mechanism and decrease the tensile stress in the transverse direction. The parametric study shows that low content steel fibers could delay the crack initiation of slab around the large diameter stud, and the CFRP bar with normal elastic modulus and the standard reinforcement ratio has good resistance to splitting crack growth in headed stud shear connectors.

• Structural Engineering and Mechanics
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• 제81권5호
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• pp.591-606
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• 2022

When the friction pendulum system and shear keys work together to resist the ground motion, which inclined inputs (non 45°) to the bridge structure, the shear keys in XY direction will be sheared asynchronously, endowed the friction pendulum system with a violent curvilinear motion on the sliding surface during earthquakes. In view of this situation, firstly, this paper abandons the equivalent linearization model of friction and constructs a Spring-Coulomb friction plane isolation system with XY shear keys, and then makes a detailed mechanical analysis of the movement process of friction pendulum system, next, this paper establishes the mathematical model of structural time history response calculation by using the step-by-step integration method, finally, it compiles the corresponding computer program to realize the numerical calculation. The results show that the calculation method in this paper takes advantage of the characteristic that the friction force is always µmg, and creatively uses the "circle making method" to express the change process of the friction force and resultant force of the friction pendulum system in any calculation time step, which can effectively solve the temporal nonlinear action of the plane friction; Compared with the response obtained by the calculation method in this paper, the peak values of acceleration response and displacement response calculated by the unidirectional calculation model, which used in the traditional research of the friction pendulum system, are smaller, so the unidirectional calculation model is not safe.

• 한국지진공학회논문집
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• 제26권6호
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• pp.227-235
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• 2022

For a member model in nonlinear structural analysis, a lumped plastic model that idealizes its flexural bending, shear, and axial behaviors by springs with the nonlinear hysteretic model is widely adopted because of its simplicity and transparency compared to the other rigorous finite element methods. On the other hand, a challenging task in its numerical solution is to satisfy the equilibrium condition between nonlinear flexural bending and shear springs connected in series. Since the local forces between flexural and shear springs are not balanced when one or both springs experience stiffness changes (e.g., cracking, yielding, and unloading), the additional unbalanced force due to overshooting or undershooting each spring force is also generated. This paper introduces an iterative scheme for numerical solutions satisfying the equilibrium conditions between flexural bending and shear springs. The effect of equilibrium iteration on analysis results is shown by comparing the results obtained from the proposed method to those from the conventional scheme, where the equilibrium condition is not perfectly satisfied.

• 한국지반공학회논문집
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• 제19권6호
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• pp.285-298
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• 2003

본 연구에서는 경사판 시험기를 이용하여 매립지에 흔히 나타나는 토목섬유/토목섬유, 토목섬유/모래의 접촉 마찰특성을 평가하였다. 경사판 시험기는 연직응력이 낮은 상태에서의 전단 거동을 정확히 모사하는 시험기로 널리 알려져 있으며, 본 연구에서는 이 시험기를 이용하여 각 접촉면의 마찰각을 평가하는 동시에, 각 토목섬유에 유발되는 인장력도 측정하였다. 실험 결과, 연직응력의 크기, 토목섬유의 종류, 토목섬유의 흙의 구성에 따라 접촉면의 마찰각과 토목섬유에 유발되는 인장력이 각각 다르게 측정됨을 확인하였다. 한편, 본 연구에서는 모래/지오텍스타일/지오멤브레인, 즉 두개의 접촉면을 동시에 모사하는 실험을 실시하여, 지오멤브레인 상부에 위치하는 지오텍스타일로 인해 지오멤브레인에 유발되는 인장력이 감소함을 관찰하였다. 본 연구 결과는 동일한 접촉면을 대상으로 실시된 직접전단 시험 결과와 비교하였으며, 마지막으로 상자의 변위가 발생하기 시작하는 시점, 즉 각 접촉면의 한계 경사에서 토목섬유에 유발되는 인장력을 기존에 제안된 해석해와 비교하여, 해석해의 정확도와 설계시 적용 가능성에 대하여 고찰하였다.

• 대한조선학회논문집
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• 제54권4호
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• pp.352-359
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• 2017

Because the Energy Efficiency Design Index(EEDI) came into effect in 2013, it is necessary to develop a new technology to overcome $CO_2$ emission regulations. In structural design viewpoint, lots of researches are carried out to develop eco-friendly and high fuel efficiency ships by weight reduction. By using the automated compartment arrangement system and automated structural design algorithm which were developed by the authors, new researches are performing to combine the above two systems. However, the effect of weight reduction was not significant because structural designs by using these systems for the midship part was carried out only focused on the minimum still water bending moment. In this paper, at first, good compartment arrangements which give the minimum still water bending moment and(or) shear force were chosen by using the automated compartment system. And then, influence of shear force on weight reduction was investigated by using the automated structural design algorithm considering longitudinal strength, local strength and shear strength of longitudinal members in cargo holds. Conclusively, it is necessary to consider the minimum still water bending moment and shear force simultaneously to reduce the weight of mid-sized bulk carrier. Also, good compartment arrangement which gives much more weight reduction compared with existing ship was proposed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.257-262
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• 1999

On End Milling Process predict the cutting force is important. Dynamics the shear stress is the main parameter influencing the energy requirement in machining. It is well known that a nonzero force is obtained when cutting forces measured at different feed rates but otherwise constant cutting conditions are extrapolated to zero feed rate. In this paper, the cutting force measured in end-milling is compared with the simulated force models. The result show that stress measured in cutting is consistent with that stresses predicted.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.190-193
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• 2006

The definition of the Dual system is that the total seismic force resistance is to be provided by the combination of the moment frame and the shear walls or braced frames in proportion to their stiffness and the moment frame shall be capable of resisting at least 25% of the design force in Korean Building Code 2005 (KBC 2005). But, the definition of moment frame is ambiguous whether the moment frame include the imaginary columns in the shear wall (Case I) or include only the columns outside the shear wall (Case II). 60-story RC building was designed as dual system for Case I and Case II, and the required strength and reinforcement are compared. Moment and axial capacity of the shear wall of Case II decreased about 5% due to the absence of the column in the shear wall. The requirement of upper and bottom reinforcement of slab in Case II increased 13% and 40%, respectively, when compared to those of Case I. The required longitudinal reinforcement in columns for Case II is about 1.5 times larger than that of Case I.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.887-890
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• 2001

In end milling process the underformed chip thickness and the cutting force components very periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying underformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting mode. According to this analysis, when cutting Inconel 718.61% of the total energy is consumed in the shear process and the balance is consumed in the friction process.