• Title/Summary/Keyword: Opening Load

Search Result 410, Processing Time 0.026 seconds

Effects of Strain Hardening Exponents on the Retardation of Fatigue Crack Propagation (가공경화지수가 피로균열 지연거동에 끼치는 영향)

  • 김상철;강동명
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.14 no.5
    • /
    • pp.1193-1199
    • /
    • 1990
  • Effects of strain hardening exponents on the behavior of fatigue crack propagation are experimentally investigated. The retardation effect of fatigue crack propagation after single overloading is investigated in relation to strain hardening exponent and crack closure. A relationship between crack opening ratio and strain hardening exponents is inspected through an examination of the crack closure behavior. An empirical equation relating retardation effect of fatigue crack propagation after single overloading, percent peak load and strain hardening exponent of materials is proposed.

The Study on the Cooling Effects of the Atrium Interiors for the Roof Watering System by a Scaled Model (축소모형을 이용한 지붕담수시스템을 활용한 아트리움 실내의 냉각효과에 관한 연구)

  • Chung, Yu Gun
    • KIEAE Journal
    • /
    • v.9 no.6
    • /
    • pp.51-56
    • /
    • 2009
  • The most important advantages of atrium buildings are to allow the abundant natural lighting and outside views. However, the abundant lighting frequently causes to increase a cooling load in summer. The roof watering systems are useful to reduce the cooling load and save the energy. This study aims to investigate the effects of the roof watering system in atrium through the scaled model experiments. For the study, the 1/20 scaled model was made and tests were performed under the clear sky conditions through August 24 to september 7 in 2008. The model size was $45{\times}45{\times}60(cm)$ and depth of roof water was 3(cm). As results, the thermal effects of two types of atrium(roof opening, and roof and front opening,) were evaluated through the experimental points and conditions. It is expected to use the results for the next research to develop the practical roof watering systems for atrium.

An Experimental Study on Behavior of Box Girder considering Middle Diaphragm Shapes (중간격벽의 형상을 고려한 상자형 거동에 대한 실험적 연구)

  • 정희효;이승열
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.15 no.3
    • /
    • pp.501-510
    • /
    • 2002
  • The middle diaphragm of box girder is to prevent the deformation of the cross section of box girder, to distribute load produced at upper flange onto the both sides of web. But if inner space of box girder is barred by the middle diaphragm, it is impossible to use in inner space of box girder and it is felt constraint on maintenance-management. The effect of middle diaphragm of box girder is intended to be expressed by the stiffness of diaphragm in comparing the diaphragm with opening of box girder with diaphragm without opening of box girder through the experiment.

Analysis of Compression Characteristics of the Steel Plate-Concrete Wall Structures with Openings (개구부가 있는 강판콘크리트 벽체의 압축특성 분석)

  • Choi, Byong-Jeong
    • Journal of Korean Society of Steel Construction
    • /
    • v.24 no.3
    • /
    • pp.245-256
    • /
    • 2012
  • The objective of this study is to investigate the effect of the openings on the structural behavior of SC walls. The test parameters were with or without the reinforcing of openings and sleeve thickness. The common failure showed that the crack in the concrete progressed with the plate's local buckling between the shear connectors. The failure of the openings showed that the vertical wall of the sleeve buckled toward the opening inside. The plate buckling load showed a similar value with or without the sleeve of the opening, respectively. However, the maximum compressive strength of the specimen without the opening was higher than that of specimen with the opening.

A Study on the Buckling Strength of Plate Panels with Opening (유공판의 좌굴강도에 관한 연구)

  • Kim, Ul-Nyeon;Choe, Ick-Heung;Kwon, Jin-Chil;Paik, Jeom-Kee
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.47 no.2
    • /
    • pp.210-224
    • /
    • 2010
  • The aim of the present study is to investigate the buckling strength of plates and stiffened panels with opening under transverse thrust and shear actions. It is observed that the existing design formulation for critical-buckling strength of plates are not valid for perforated plates, because the current design formulation trends can significantly overestimate or underestimate the load-carrying capacity of plates when plates have large opening and/or are thick. A series of eigen value and elastic.plastic large deflection finite element analyses are carried out with varying the aspect ratio of plate, the opening size and location on plate until and after the ultimate strength is reached. Based on the results obtained from the present study, closed-form design formulations for the elastic buckling strength of plates and stiffened panels with opening are derived. The derived design formulations are considered plasticity correction of the material and verified by experimental tests and results of nonlinear finite element computations.

Strengthening of Cutouts in Existing One-Way Spanning R. C. Flat Slabs Using CFRP Sheets

  • Shehab, Hamdy K.;Eisa, Ahmed S.;El-Awady, Kareem A.
    • International Journal of Concrete Structures and Materials
    • /
    • v.11 no.2
    • /
    • pp.327-341
    • /
    • 2017
  • Openings in slabs are usually required for many different applications such as aeriation ducts and air conditioning. Opening in concrete slabs due to cutouts significantly decrease the member stiffness. There are different techniques to strengthen slabs with opening cutouts. This study presents experimental and numerical investigations on the use of Carbon Fiber Reinforced Polymers (CFRP) as strengthening material to strengthen and restore the load carrying capacity of R.C. slabs after having cutout in the hogging moment region. The experimental program consisted of testing five (oneway spanning R.C. flat slabs) with overhang. All slabs were prismatic, rectangular in cross-section and nominally 2000 mm long, 1000 mm width, and 100 mm thickness with a clear span (distance between supports) of 1200 mm and the overhang length is 700 mm. All slabs were loaded up to 30 kN (45% of ultimate load for reference slab, before yielding of the longitudinal reinforcement), then the load was kept constant during cutting concrete and steel bars (producing cut out). After that operation, slabs were loaded till failure. An analytical study using finite element analysis (FEA) is performed using the commercial software ANSYS. The FEA has been validated and calibrated using the experimental results. The FE model was found to be in a good agreement with the experimental results. The investigated key parameters were slab aspect ratio for the opening ratios of [1:1, 2:1], CFRP layers and the laminates widths, positions for cutouts and the CFRP configurations around cutouts.

Tensile Stress-Crack Opening Relationship of Ultra High Performance Cementitious Composites(UHPCC) Used for Bridge Decks (바닥판 적용 초고성능 시멘트 복합체의 인장응력-균열개구 관계)

  • Kwon, Seung Hee;Lee, Seung Kook;Park, Sung Yong;Cho, Keun Hee;Cho, Jeong Rae
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.17 no.1
    • /
    • pp.46-54
    • /
    • 2013
  • Two different UHPCCs having different fiber lengths and volume fractions are considered to be applied to bridge decks. The objective of this study is to estimate cracking resistance of the two UHPCCs. The notched beam tests were performed with the UHPCCs, and the relationships between load and CMOD(Crack Mouth Opening Displacement) were obtained from the tests. The tensile stress and crack opening relationships optimally fitting the measured load-CMOD curves were found through the inverse analyses. The UHPCC with 2% volume fraction of 13 mm long fiber has lower fracture energy than the UHPCC with 0.5% and 1.0% volume fractions of 16.3 mm and 19.5 mm long fibers, respectively. It indicates that the latter UHPCC is more effective in uniformly distributing crack formation and reducing crack width.

Fracture Characteristics of Concrete at Early Ages (초기재령 콘크리트의 파괴특성)

  • Lee, Yun;Kim, Jin-Keun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2001.05a
    • /
    • pp.215-220
    • /
    • 2001
  • The objective of this study is to examine the fracture characteristics of concrete at early ages such as critical stress intensity factor, critical crack-tip opening displacement, fracture energy based on the concepts of the effective-elastic crack model and the cohesive crack model. A wedge splitting test for Mode I was performed on cubic wedge specimens with a notch at the edge. By varying strength and age, load-crack mouth opening displacement curves were obtained and the results were analyzed by linear elastic fracture mechanics. The results from the test and analysis showed that critical stress intensity factor and fracture energy increased, and critical crack-tip opening displacement decreased with concrete age from 1 day to 28 days. The obtained fracture parameters at early ages may be used as a fracture criterion and an input data for finite element analysis of concrete at early ages.

  • PDF

A Study on Structural reinforcement suggestions for improvement of Seismic Performance of Masonry Buildings in rural areas (농촌지역의 조적조 건축물의 내진성능 개선을 위한 구조적 보강법 제안에 관한 연구)

  • Lee, Deog-Yong;Kim, Il-Jung
    • Journal of the Korean Institute of Rural Architecture
    • /
    • v.15 no.4
    • /
    • pp.51-58
    • /
    • 2013
  • This study Masonry Buildings in rural areas, due to the lateral load resistance for seismic reinforcement method is proposed. Some of the proposed methods for reinforcement directly through finite element analysis to evaluate the change in frequency. The results for the following: This paper has the object of investigating natural frequencies of opening thick plates on Pasternak foundation by means of finite element method and providing Kinematic design data for mat of building structures. In this paper, vibration analysis of rectangular opening thick plate is done by use of Serendipity finite element with 8 nodes by considering shearing strain of plate. It is shown that natrural frequencies depend on not only Winkler foundation parameter but also shear foundation parameter, opening position.

Crack Opening Displacement Analysis of Complex Cracked Pipes based on Enhanced Reference Stress Method (개선된 참조응력법을 이용한 복합균열이 존재하는 배관의 균열개구변위 계산)

  • Huh, Nam-Su;Kim, Yun-Jae;Kim, Young-Jin
    • Proceedings of the KSME Conference
    • /
    • 2001.11a
    • /
    • pp.80-86
    • /
    • 2001
  • An engineering estimation equation for the crack opening displacement (COD) is proposed for a complex cracked pipe, based on the reference stress approach. To define the reference stress, a simple plastic limit load analysis for the complex cracked pipe subjected to combined bending and tension is performed considering the crack closure effect in the compressive-stressed region. Comparison with ten published test data and the results from existing method shows that the present method not only reduces non-conservatism associated with the existing method, but also provides consistent and overall satisfactory results.

  • PDF