• Title/Summary/Keyword: 휨 강성

Search Result 557, Processing Time 0.027 seconds

Quality Characteristics of Cookies Prepared with Varied levels of Shredded Garlics (다양한 수준의 마늘 첨가 쿠키의 품질 특성 연구)

  • L.Kim, Hye-Young;Jeong, Su-Jin;Heo, Mi-Yeon;Kim, Kang-Sung
    • Korean Journal of Food Science and Technology
    • /
    • v.34 no.4
    • /
    • pp.637-641
    • /
    • 2002
  • The purpose of this study was to provide the basic information on the cookies made with garlic and to investigate quality characteristics of them using chemical and sensory evaluation of cookies. Cookie samples were prepared with shredded garlic at varied levels of 0, 3, 6 and 9%. The pH of the dough significantly decreased by the addition of garlic. Dough density of control showed significantly lower values than those of 3% added sample groups. Spreadability of control had significantly higher values than the other samples. Texture measurement showed that the addition of garlic had no significant effect on cookie texture. Sensory evaluation resulted that the properties of crack, garlic aroma, garlic taste and brittleness of cookies tended to increase as the addition levels of garlic were increased. The cookies with 3% and 6% garlic had similar or significantly higher acceptance scores in all of the properties examined than those of control.

Design Methodology on Steel-type Breakwater II. Pile Design Procedure (철재형 이안제 설계기법 연구 II. 하부기초 설계 단계)

  • Kwon, Oh-Kyun;Oh, Se-Boong;Kweon, Hyuck-Min
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.11 no.3
    • /
    • pp.219-228
    • /
    • 2011
  • In this paper, the design procedure of substructure of the steel-type breakwater was described and the actual foundation design was performed for the test bed. The site investigation was executed at the Osan-port area, in Uljin, Gyeongbuk, where the steeltype detached breakwater is constructed. The foundation mainly depends on the lateral load and uplift force due to the wave force. Since the superstructure is stuck out about 9.0m from the ocean bed, the foundation must resist on the lateral force and bending moment. After considering various factors, the foundation type of this structure was determined by the steel pipe pile(${\varphi}711{\times}t12mm$). On the stability of pile foundation, the safety factors of the pile on the compressive, lateral and uplift forces were grater than the minimum factor of safety. The displacements of pile under the working load were evaluated as the values below the permissible ones. Based on the subgrade reaction method, we evaluated the relationship of subgrade reaction and displacement for the lateral and the vertical directions in the layers. The structural analyses along with the foundation were perfomed and the effect of pile foundations were compared quantitatively.

A Study on the Evaluation of Safety Stiffness from Ship's Mooring Bollards (선박 접안용 계선주의 안전 강성 평가에 관한 연구)

  • Yu, Yong-Ung;Kim, Seung-Yeon;Lee, Yun-Sok
    • Journal of Navigation and Port Research
    • /
    • v.43 no.1
    • /
    • pp.9-15
    • /
    • 2019
  • Mooring bollards are the mandatory facility in ports for they are the objects used to fasten the ship to its position at the berth. All the mooring bollards were installed following suggested sizes, numbers, materials and shape of installation according to Port and Fishing Design Standards. However, Korea has no management standard for use of mooring bollards to safety in ship berthing. In this research, the installation standard for mooring bollards including the holding power applied to mooring bollards in berthing was studied. Also, the performance of mooring bollards for minimum safety guarantee in berthing based on research of various specification by their sizes was analyzed. The analysis on mooring bollards was examined by each power on mooring bollards from the applied force in berthing divided into horizontal and vertical direction in order to examine the performance of domestic mooring bollards, the limit force is calculated based on detailed specification research result. As a result, the working stress according to the towing force was found to be at least 150Mpa and it was evaluated to be 60% of the limit strength. Also, by comparing each forces, the appropriateness was examined and the specification of maximum capability calculated. This performance evaluation method based on detail specification of mooring bollards will be expected to be useful to examine the appropriateness of mooring bollards for various types of vessel in berthing and to develop maintenance and management standard through the performance change evaluation referring to mooring bollard detailed specification changes.

Analytical Study on Vibrational Properties of High Damping Polymer Concrete (고 감쇠 폴리머 콘크리트의 진동 특성에 관한 해석적 연구)

  • Kim, Jeong-Jin;Kim, Jong
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.24 no.5
    • /
    • pp.119-125
    • /
    • 2020
  • Research on high-attenuation concrete for the vibration reduction performance by mixing epoxy-based synthetic resins and aggregates is actively being conducted. The curing time of high-attenuation concrete is very short because water is not used, and the physical and dynamic properties are very excellent. therefore, it is expected to be widely used in building structures requiring reduction of interior-floor noise and vibration. Furthermore, A way to expand the applicability of the high-damping concrete mixed with polymer in the field of reinforcement material have been variously studied. In order to replace polymer concrete with ordirnary concrete and existing anti-vibration reinforcement material, it is necessary to review overall vibration reduction performance considering physical properties, dynamic properties, productivity and field applicability. In this study, the physical and dynamic properties of polymer concrete by epoxy mixing ratio compared with ordirnary concrete. As a result, the elastic modulus was similar. On the other hand, polymer concrete for the compressive, tensile, and flexural strengths was quite more excellent. In particular, the measured tensile strength of polymer concrete was 4-10 times higher than that of ordirnary concrete. it was a big difference, and the frequency response function and damping ratio was studied through modal test and finite element analysis model. The dynamic stiffness of polymer concrete was 20% greater than that of ordirnary concrete, and the damping ratio of polymer concrete was approximately 3 times more than that of ordirnary concrete.

Estimation of Appropriate Reinforcement Length of Casing for the Pile of Pile Bent System through Numerical Analysis (수치해석을 통한 단일형 현장타설말뚝 외부강관의 적정 보강길이 산정)

  • Yang, Wooyeol;Kim, Wanho;Lee, Kangil
    • Journal of the Korean GEO-environmental Society
    • /
    • v.22 no.6
    • /
    • pp.5-15
    • /
    • 2021
  • One of the construction methods applied as a pier foundation type is a single type cast-in-place pile. In applying a pile bent system as a foundation type, the main concern in designing can be said to secure the lateral bearing capacity of pile structure in system. In addition, to increase the rigidity of the pile structure, a method of increasing the lateral bearing capacity by reinforcing the pile structure with a casing has been used. However, although the reinforcing effect and appropriate reinforcing length of casing may vary depending on the soil conditions, there is insufficient studies on this, and for this reason, the entire pile structure in a pile bent system is reinforced with a casing, in the field. In addition, if the length of the entire pile is reinforced with a casing, it may lead to delays in construction and increase in construction costs. That is, in order to more effectively reinforce the pile structure with a casing, it is necessary to study the lateral bearing characteristics of the reinforced pile structure in system. And it should be determined the appropriate reinforcing length of the casing from the evaluated bearing characteristics. Therefore, in this study, the lateral bearing characteristics of piles applied with the reinforcing length of casing for each condition were evaluated through a numerical analysis. And, based on the analysis results, the appropriate reinforcing length of casing was proposed. As a result of the study, it was found that in order to effectively increase the lateral bearing capacity of pile structure, the reinforcing length of casing should be applied twice the influence range of the bending behavior of the pile, 1/β.

The Experimental Study of the Ultimate Behavior of an Avalanche Tunnel Corner Rigid Joint Composited with a Centrifugal Formed Beam (초고강도 원심성형 보가 합성된 피암터널 우각부의 극한거동에 관한 실험연구)

  • Lee, Doo-Sung;Kim, Sung-Jin;Kim, Jeong-Hoi
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.26 no.6
    • /
    • pp.128-138
    • /
    • 2022
  • In this study, in order to apply ultra-high-strength concrete beams of 100 MPa or more manufactured by centrifugal molding as the superstructure of the avalanche tunnel, the purpose is to verify the structural safety of the corner rigid joint in which the centrifugal molded beam is integrated with the substructure, which is the negative moment area. A full-size specimen was manufactured, and loading tests and analysis studies were performed. In order to expect the same effect that the maximum moment occurs in the corner joint part of the upper slab end when the standard model of the avalanche tunnel is designed with a load combination according to the specification, a modified cantilever type structural model specimen was manufactured and the corner rigid joint was fixedly connected. A study was performed to determine the performance of the method and the optimal connection construction method. The test results demonstrated that the proposed connection system outperforms others. Despite having differences in joint connection construction type, stable flexural behavior was shown in all the tested specimens. The proposed method also outperformed the behavior of centrifugally formed beams and upper slabs. The behavior of the corner rigid joint analysis model according to the F.E. analysis showed slightly greater stiffness compared to the results of the experiment, but the overall behavior was almost similar. Therefore, there is no structural problem in the construction of the corner rigid joint between the centrifugally formed beam and the wall developed in this study.

Examination of Root Causes of Buckling in the Stern Structure of an Oil Tanker using Numerical Modeling (수치해석 모델링을 이용한 유조선 선미부 구조에 발생한 좌굴 발생 원인 검토)

  • Myung-Su Yi;Joo-Shin Park
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.28 no.7
    • /
    • pp.1259-1266
    • /
    • 2022
  • Recently, due to the specialization of structural design standards and evaluation methods, the classification rules are being integrated. A good example is the common international rules (CSR). However, detailed regulations are presented only for the cargo hold area where the longitudinal load is greatly applied, and no specific evaluation guidelines exist for the bow and stern structures. Structural design of the mentioned area is carried out depending on the design experience of the shipbuilder, and because no clear standard exists even in the classification, determining the root cause is difficult even if a structural damage problem occurs. In this study, an engineering-based solution was presented to identify the root cause of representative cases of buckling damage that occurs mainly in the stern. Buckling may occur at the panel wall owing to hull girder bending moment acting on the stern structure, and the plate thickness must be increased or vertical stiffeners must be added to increase the buckling rigidity. For structural strength verification based on finite element analysis modeling, reasonable solutions for load conditions, boundary conditions, modeling methods, and evaluation criteria were presented. This result is expected to be helpful in examining the structural strength of the stern part of similar carriers in the future.

The Case Study of Design on Steel Pipe Sheet Pile for Earth Retaining Wall on Deep Excavation (대심도 지반굴착을 위한 벽강관말뚝 흙막이공법의 설계 사례 연구)

  • Byung-Il Kim;Jong-Ku Lee;Kyoung-Tae Kim;Kang-Han Hong;Sang-Jae Han
    • Journal of the Korean Geosynthetics Society
    • /
    • v.22 no.1
    • /
    • pp.53-66
    • /
    • 2023
  • In this study, the results of the elasto-plastic beam analysis, finite element analysis and optimization design of the steel pipe sheet pile applied as an earth retaining wall under the deep excavation were presented. Through this study, it was found that the high-strength and sea resistant steel pipe has high allowable stress, excellent structural properties, favorable corrosion, and high utilization as an earth retaining wall, and the C-Y type joint has significantly improved the tensile strength and stiffness compared to the traditional P-P type. In addition, it was investigated that even if the leak or defect of the wall occurs during construction, it has the advantage of being able to be repaired reliably through welding and overlapping. In the case of steel pipe wall, they were evaluated as the best in views of the deep excavation due to the large allowable bending stress and deformation flexibility for the same horizontal displacement than CIP or slurry wall. Elasto-plastic and finite element analysis were conducted in consideration of ground excavation under large-scale earth pressure (uneven pressure), and the results were compared with each other. Quantitative maximum value were found to be similar between the two methods for each item, such as excavation behavior, wall displacement, or member force, and both analysis method were found to be applicable in design for steel pipe sheet pile wall. Finally, it was found that economical design was possible when determining the thinnest filling method with concrete rather than the thickest hollow shape in the same diameter, and the depth (the embedded length through normality evaluation) without rapidly change in displacement and member force.

Dynamic p-y Backbone Curves for a Pile in Saturated Sand (포화 사질토 지반에서의 동적 p-y 중추곡선)

  • Yang, Eui-Kyu;Yoo, Min-Taek;Kim, Hyun-Uk;Kim, Myoung-Mo
    • Journal of the Korean Geotechnical Society
    • /
    • v.25 no.11
    • /
    • pp.27-38
    • /
    • 2009
  • In this study, a series of 1 g shaking table model pile tests were carried out in saturated dense and loose sand to evaluate dynamic p-y curves for various conditions of flexural stiffness of a pile shaft, acceleration frequency and acceleration amplitude for input loads. Dynamic p-y backbone curve which can be applied to pseudo static analysis for saturated dense sand was proposed as a hyperbolic function by connecting the peak points of the experimental p-y curves, which corresponded to maximum soil resistances. In order to represent the backbone curve numerically, empirical equations were developed for the initial stiffness ($k_{ini}$) and the ultimate capacity ($p_u$) of soils as a function of a friction angle and a confining stress. The applicability of a p-y backbone curve was evaluated based on the centrifuge test results of other researchers cited in literature, and this suggested backbone curve was also compared with the currently available p-y curves. And also, the scaling factor ($S_F$) to account for the degradation of soil resistance according to the excess pore pressure was developed from the results of saturated loose sand.

Hybrid Structural Health Monitoring of Steel Plate-Girder Bridges using Acceleration-Impedance Features (가속도-임피던스 특성을 이용한 강판형교의 하이브리드 구조건전성 모니터링)

  • Hong, Dong-Soo;Do, Han-Sung;Na, Won-Bae;Kim, Jeong-Tae
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.29 no.1A
    • /
    • pp.61-73
    • /
    • 2009
  • In this paper, hybrid health monitoring techniques using acceleration-impedance features are newly proposed to detect two damage-type in steel plate-girder bridges, which are girder's stiffness-loss and support perturbation. The hybrid techniques mainly consists of three sequential phases: 1) to alarm the occurrence of damage in global manner, 2) to classify the alarmed damage into subsystems of the structure, and 3) to estimate the classified damage in detail using methods suitable for the subsystems. In the first phase, the global occurrence of damage is alarmed by monitoring changes in acceleration features. In the second phase, the alarmed damage is classified into subsystems by recognizing patterns of impedance features. In the final phase, the location and the extent of damage are estimated by using modal strain energy-based damage index method and root mean square deviation (RMSD) method. The feasibility of the proposed hybrid technique is evaluated on a laboratory-scaled steel plate-girder bridge model for which hybrid acceleration-impedance signatures were measured for several damage scenarios. Also, the effect of temperature on the accuracy of the impedance-based damage monitoring results are experimentally examined from combined scenarios of support damage cases and temperature changes.