• 제목/요약/키워드: Strength development model

검색결과 700건 처리시간 0.035초

구조방정식모델을 이용한 직무만족도 평가모형 개발 (Development of Job Satisfaction Measurement Model Using Structural Equation Model)

  • 전영호
    • 품질경영학회지
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    • 제39권1호
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    • pp.90-97
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    • 2011
  • The purpose of this study is to analyze various factors comprising a job satisfaction; determine possible factors that affects job satisfaction. Job satisfaction model is designed to evaluate major factors, such as job stress and strength, and to assess relationship between these factors. Partial least squares algorithm is used to develop a job satisfaction measurement model. To evaluate validity of developed model, survey data of health insurance review and assessment service is to applied.

국내 콘크리트 강도 발현을 고려한 시멘트 상수의 적절성 연구 (A Study on Appropriacy of Cement Constant Considering Strength Development of Domestic Concrete)

  • 최연왕;정재권;이광명;김지상;정상화;문재흠
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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    • pp.321-322
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    • 2010
  • 본 논문은 국내 재료성능모델 개발을 위하여 새로운 시간경과에 따른 코크리트 강도 발현 모델식을 제안 하고자 한다.

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새로운 겉보기 활성에너지 함수에 의한 플라이애시 콘크리트의 압축강도 예측 (Prediction of Compressive Strength of Fly Ash Concrete by a New Apparent Activation Energy Function)

  • 한상훈;김진근;박연동
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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    • pp.947-952
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    • 2001
  • The prediction model is proposed to estimate the variation of compressive strength of fly ash concrete with aging. After analyzing the experimental result with the model, the regression results are presented according to fly ash replacement content and water/cement ratio. Based on the regression results, the influence of fly ash replacement content and water/cement ratio on apparent activation energy was investigated. According to the analysis, the model provides a good estimate of compressive strength development of fly ash concrete with aging. As the fly ash replacement content increases, the limiting relative compressive strength and initial apparent activation energy become greater. The concrete with water/cement ratio smaller than 0.40 shows that the limiting relative compressive strength and apparent activation energy are nearly constant according to water/cement ratio. But, the concrete with water/cement ratio greater than 0.40 has the increasing limiting relative compressive strength and apparent activation energy with increasing water/cement ratio.

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Towards improved models of shear strength degradation in reinforced concrete members

  • Aschheim, Mark
    • Structural Engineering and Mechanics
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    • 제9권6호
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    • pp.601-613
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    • 2000
  • Existing models for the shear strength degradation of reinforced concrete members present varied conceptual approaches to interpreting test data. The relative superiority of one approach over the others is difficult to determine, particularly given the sparseness of ideal test data. Nevertheless, existing models are compared using a suite of test data that were used for the development of one such model, and significant differences emerge. Rather than relying purely on column test data, the body of knowledge concerning degradation of concrete as a material is considered. Confined concrete relations are examined to infer details of the degradation process, and to establish a framework for developing phenomenologically-based models for shear strength degradation in reinforced concrete members. The possibility of linking column shear strength degradation with material degradation phenomena is explored with a simple model. The model is applied to the results of 7 column tests, and it is found that such a link is sustainable. It is expected that models founded on material degradation phenomena will be more reliable and more broadly applicable than the current generation of empirical shear strength degradation models.

강섬유의 형상비와 혼입률에 따른 강섬유 보강 콘크리트 보의 역학적 특성 추정 모형 개발 (Development of Estimation of Model for Mechanical Properties of Steel Fiber Reinforced Concrete according to Aspect Ratio and Volume Fraction of Steel Fiber)

  • 곽계환;황해성;성배경;장화섭
    • 한국농공학회논문집
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    • 제48권3호
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    • pp.85-94
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    • 2006
  • Practially useful method of steel fiber for construction work is presented in this study. The most important purpose of this study is to develop a model which can predict mechanical behavior of the structure according to aspect ratio and volume fraction of steel fiber. Experiments on compressive strength, elastic modulus, and splitting strength were performed with self-made cylindrical specimens of variable aspect ratios and volume fractions. The experiment showed that compressive strength was not in direct proportion to volume fraction which doesn't seem to have great influence over compressive strength. However, splitting strength showed almost direct proportion to aspect ratio and volume fraction. Improvement of optimal efficiency was confirmed when the aspect ratio was 70. Experiments on flexural strength, fracture energy, and characteristic length were carried out with self-manufactured beams with notch. As a result, increases of flexural strength, fracture energy, and characteristic length according to increase of volume fraction tend to be prominent when aspect ratio is 70. The steel fiber improves concrete to be more ductile and tough. Moreover, regression analysis was the performed and predictable model was developed after determining variables. With comparison and analysis of suggested estimated values and measured data, reliance of the model was verified.

Finite Element Model based on Strain Tests for Predicting Bending Strength of Small Gears for Aircraft

  • Kim, Taehyung;Seok, Taehyeon;Seol, Jin-woon;Lee, Byung-ho;Kwon, Byung-gi;Choi, Jong-yoon
    • 항공우주시스템공학회지
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    • 제14권6호
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    • pp.91-99
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    • 2020
  • This study proposes a finite element (FE) model for predicting the bending strength of small gears used in electro-mechanical actuators for aircraft. First, a strain gauge was attached to the tooth root of test gear, and the strain was measured. Subsequently, the FE model was applied to calculate the strain of the test gear, and the modeled strain was compared with the experimental strain. The results confirmed that the FE strain was very close to the experimental strain and the FE model was valid. This FE model was extended to the bending strength analysis of several small gear tooth models. The bending strengths of all the tooth models were almost identical to the ISO theoretical bending strength. Finally, the FE model was validated and the reliability of the modeled bending strength was evaluated through the strain measurement experiment.

Curvature ductility of confined HSC beams

  • Bouzid Haytham;Idriss Rouaz;Sahnoune Ahmed;Benferhat Rabia;Tahar Hassaine Daouadji
    • Structural Engineering and Mechanics
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    • 제89권6호
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    • pp.579-588
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    • 2024
  • The present paper investigates the curvature ductility of confined reinforced concrete (RC) beams with normal (NSC) and high strength concrete (HSC). For the purpose of predicting the curvature ductility factor, an analytical model was developed based on the equilibrium of internal forces of confined concrete and reinforcement. In this context, the curvatures were calculated at first yielding of tension reinforcement and at ultimate when the confined concrete strain reaches the ultimate value. To best simulate the situation of confined RC beams in flexure, a modified version of an ancient confined concrete model was adopted for this study. In order to show the accuracy of the proposed model, an experimental database was collected from the literature. The statistical comparison between experimental and predicted results showed that the proposed model has a good performance. Then, the data generated from the validated theoretical model were used to train the artificial neural network (ANN) prediction model. The R2 values for theoretical and experimental results are equal to 0.98 and 0.95, respectively which proves the high performance of the ANN model. Finally, a parametric study was implemented to analyze the effect of different parameters on the curvature ductility factor using theoretical and ANN models. The results are similar to those extracted from experiments, where the concrete strength, the compression reinforcement ratio, the yield strength, and the volumetric ratio of transverse reinforcement have a positive effect. In contrast, the ratio and the yield strength of tension reinforcement have a negative effect.

Bond strength prediction of steel bars in low strength concrete by using ANN

  • Ahmad, Sohaib;Pilakoutas, Kypros;Rafi, Muhammad M.;Zaman, Qaiser U.
    • Computers and Concrete
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    • 제22권2호
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    • pp.249-259
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    • 2018
  • This paper presents Artificial Neural Network (ANN) models for evaluating bond strength of deformed, plain and cold formed bars in low strength concrete. The ANN models were implemented using the experimental database developed by conducting experiments in three different universities on total of 138 pullout and 108 splitting specimens under monotonic loading. The key parameters examined in the experiments are low strength concrete, bar development length, concrete cover, rebar type (deformed, cold-formed, plain) and diameter. These deficient parameters are typically found in non-engineered reinforced concrete structures of developing countries. To develop ANN bond model for each bar type, four inputs (the low strength concrete, development length, concrete cover and bar diameter) are used for training the neurons in the network. Multi-Layer-Perceptron was trained according to a back-propagation algorithm. The ANN bond model for deformed bar consists of a single hidden layer and the 9 neurons. For Tor bar and plain bars the ANN models consist of 5 and 6 neurons and a single hidden layer, respectively. The developed ANN models are capable of predicting bond strength for both pull and splitting bond failure modes. The developed ANN models have higher coefficient of determination in training, validation and testing with good prediction and generalization capacity. The comparison of experimental bond strength values with the outcomes of ANN models showed good agreement. Moreover, the ANN model predictions by varying different parameters are also presented for all bar types.

목포항 요트산업 개발과 운영 주체 선정 (Assessment of Development and Opertation for Maritime Leisure in Mokpo Port using SWOT&AHP)

  • 장운재;금종수
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2005년도 춘계학술대회 논문집
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    • pp.451-456
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    • 2005
  • 본 연구에서는 목포항의 요트산업 운영과 개발에 관한 평가를 위한 평가모델을 제안하고자 한다. 이러한 평가를 위해 본 연구에서 제안한 모델은 SWOT와 AHP법을 통합하였다. 본 연구에서는 평가를 위해 ISM법에 의해 평가요소를 구조화한다. 그리고 계층구조는 5단계이며 3단계부터는 SWOT법이 적용된다. 또한 평가를 위해 SWOT법에서 S, W는 내부적요소로, O, T 는 내부적 요소로 구분하였다. 또한 개발 및 운영의 관점은 경제적인 관점과 해양 레져관광 개발의 두 관점을 고려하였다. 개발 및 운영주체는 제3섹터, 민간과 지자체로 구분하였다. 그 결과 강점과 기회가 우선순위가 높게 나타났고 제3섹터에 의한 개발과 운영이 선호되는 것으로 나타났다.

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SWOT&AHP을 이용한 목포항 요트산업 개발과 운영 주체 평가 (Assessment of Development and Operation for Maritime Leisure In Mokpo Port using SWOT&AHP)

  • 장운재;박성현;금종수
    • 한국항해항만학회지
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    • 제29권8호
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    • pp.715-721
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    • 2005
  • 본 연구에서는 목포항의 요트산업 운영과 개발에 관한 평가를 위한 평가모델을 제안하고자 한다. 이러한 평가를 위해 본 연구에서 제안한 모델은 SWOT와 AHP법을 통합한 것이다. 본 연구에서는 평가를 위해 ISM법에 의해 평가요소를 구조화한다. 그리고 계층구조는 5단계이며 3단계부터는 SWOT법이 적용된다. 또한 평가를 위해 SWOT법에서 O, T는 외부적요소고, O, T는 외부적 요소로 구분하였다. 또한 개발 및 운영의 관점은 경제적인 관점과 해양 레져관광 개발의 두 관점을 고려하였다. 개발 및 운영주체는 제3섹터 민간과 지자체로 구분하였다. 그 결과 강점과 기회가 우선순위가 높게 나타났고 제3섹터에 의한 개발과 운영이 선호되는 것으로 나타났다.