• 대한기계학회논문집A
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• 제25권2호
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• pp.264-274
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• 2001

An integrated fatigue strength assessment system was computerized. The system developed consists of 9 modules: user interface, cycle counting, load history construction, data searching, fatigue properties estimation, fatigue data analysis, true stress and strain analysis, expert system for crack initiation life prediction, fatigue crack initiation and propagation life prediction. Fatigue strength database also was included in this system. The fatigue expert system helps a beginner to predict a fatigue crack initiation life in fatigue strength assessment. The expert system module in this system is developed on the personal computer by using C language and UNiK, an expert system developing tool. To evaluate the system, the results of test under variable loading of SAE and failure data from a field were analyzed. The evaluation show that the system provided fatigue life prediction within 3-scatter band and gave reasonable predictions. To get more accurate predictions of fatigue life without fatigue properties, we recommend utilizing the system along with the fatigue strength database.

• 한국지반환경공학회 논문집
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• 제9권3호
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• pp.17-28
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• 2008

본 연구에서는 상수도 금속관의 공식특성에 따른 잔존 인장강도 예측모델을 제안하였다. 이들 모델중 회주철관에 대해서는 지수함수형 모델이 실측값에 대한 예측값의 상관성($R^2$)이 높게 나타났으며, 닥타일주철관과 강관 등은 선형함수인 공식특성에 따른 강도손실 모델이 더 예측력이 높은 것으로 나타났다. 국내에서 과거에 제조된 상수도 금속관의 파괴인성은 평균적으로 회주철관이 $40.46kgf/mm^2{\sqrt{mm}}$, 닥타일주철관이 $85.27kgf/mm^2{\sqrt{mm}}$, 그리고 강관이 $97.27kgf/mm^2{\sqrt{mm}}$로 나타났으며, 파괴인성을 이용한 잔존 인장강도 예측모델의 실측값에 대한 예측값의 상관성은 관종에 따라 다르나 0.44에서 0.86로 나타났다. 특히 이들 제안된 모델들을 새로운 지역에 매설된 상수관로에 대하여 적용한 결과, 결정계수가 0.76~0.78로 나타나 향후 노후 상수도 금속관의 잔존 강도를 예측하는데 활용됨으로서 합리적인 개대체 의사결정에도 도움을 줄 수 있을 것으로 판단된다.

• International Journal of Concrete Structures and Materials
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• 제3권1호
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• pp.57-61
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• 2009

The present work deals with the prediction, through models and experimental evaluation, of the bending strength of roller compacted concrete (RCC) for pavement applications. This concrete was manufactured using low cement proportioning (150 to $250\;kg/m^3$). The characterization of hardened RCC was carried out by experimental measurements of bending strengths. The predictions of these characteristics were achieved using empirical models. Comparison, of the values found in experiments with those empirically obtained, was made in order to choose and to propose the adapted and the most reliable models of prediction. The study showed that the bending strengths of the RCC mixture, experimentally found, can be also identified by models.

• Computers and Concrete
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• 제34권4호
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• pp.427-446
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• 2024

The I-shaped steel reinforced recycled aggregate concrete (SRRC) composite structure has the advantages of high bearing capacity and environmental protection, and the interfacial bond strength is an important theory. To this end, the I-shaped SRRC bond strength and its calculation based on artificial neural network (ANN) will be studied. Firstly, 39 push out tests of I-shaped SRRC were conducted, the load-slip curve has obvious regularity, which is divided into 4 segments by 3 regular points. Three bond strengths were defined based on these three rule points, and the approximate ranges of their values and the laws of influence of each factor on them were found. Secondly, the Elman ANN model used for the prediction of bond strength was established, and the parameters of Elman ANN predicting I-shaped SRRC bond strength were studied, and the effects of detailed parameters on the prediction results were revealed. Finally, the bond strength of SRRC was predicted using Elman and BP (back propagation) neural network models, both of which showed good prediction results. This study is a theoretical basis for the design and fine simulation of I-shaped SRRC composite structures.

• Smart Structures and Systems
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• 제16권3호
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• pp.497-519
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• 2015

This study discusses the use of Adaptive-Network-Based-Fuzzy-Inference-System (ANFIS) in predicting the shear strength of reinforced-concrete deep beams. 139 experimental data have been collected from renowned publications on simply supported high strength concrete deep beams. The results show that the ANFIS has strong potential as a feasible tool for predicting the shear strength of deep beams within the range of the considered input parameters. ANFIS's results are highly accurate, precise and therefore, more satisfactory. Based on the Sensitivity analysis, the shear span to depth ratio (a/d) and concrete cylinder strength ($f_c^{\prime}$) have major influence on the shear strength prediction of deep beams. The parametric study confirms the increase in shear strength of deep beams with an equal increase in the concrete strength and decrease in the shear span to-depth-ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.287-290
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• 2000

Nowadays, strength control is performed by test of compressive strength of concrete which is taken in construction filed. But because it is possible to confirm only compressive strength of concrete by that way, it is difficult to performing strength control pr process plan, So, if we can predict compressive strength of concrete, we can decide when shores and forms can be removed safety, plan process efficiently. This study intends to propose basic data for strength control as determination the time of forwoak removal through investigating propriety of strength prediction using Freiesleben function.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.442-445
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• 2004

The acoustic target strength (TS) of submarine is associated with its active detection, positioning and classification. That is, the survivability of submarine depends on its target strength. So it should be managed with all possible means. An anechoic coating to existing submarine or changing of curvature can be considered as major measures to reduce the TS of submarine. It is mainly based on the prediction of its TS. Under this circumstances, a study on the more accurate numerical methods becomes big topic for submarine design. In this paper, Kirchhoff approximation method was adopted as a numerical tool for the physical optics region. Secondly, the scaled models of submarine were built and tested in order to verify its performance. Through the comparison, it was found out that the Kirchhoff approximation method could be good design tool for the prediction of TS of submarine.

• 한국기계가공학회지
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• 제11권2호
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• pp.34-39
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• 2012

In this study, the friction welding experiment was performed by using the design of experiment. And the signal data acquired by acoustic emission sensor were analyzed to predict the tensile strength of friction welding part at friction welding process for AZ31 magnesium alloy. A dimensionless coefficient($\phi_{AE}$), which consisted in the square of AE rms and variance, was defined as the characteristic of friction welding and the prediction equation was obtained by using linear regression. As the result of analysis, it was seen that the correlation between predicted and measured values became very close and on-line prediction of the ensile strength was possible in friction welding part.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.275-278
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• 2004

In this paper, the fracture strength of the surface damaged laminates was predicted by applying the fracture strengths of the unflawed and flawed laminates. For prediction, the theoretical equation about the fracture strength of laminates was simplified applying classical laminate theory and was applied to the surface damaged laminates. Lagace's and Tsai's experimental data were used for verifying the theoretical equation. Moreover, to verify the theoretical prediction, an experiment was performed. Surface unflawed laminate and flawed laminates were fabricated and the experiments were made and these results were compared with theoretical predictions. The specimens' fiber direction was same to the tensile direction and the theoretical predictions and the experimental results were showed good agreement. Therefore, by this equation, the fracture strength of structures made of composites will be able to be predicted when the surface of the structures was damaged.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.179-182
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• 2002

Rapid Prototyping (RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys' Fused Deposition Modeling (FDM) is a typical RP process that can fabricate prototypes out of plastic materials, and the parts made from FDM were often used as load-carrying elements. Because FDM deposits materials in about $300\mutextrm{m}$ thin filament with designated orientation, parts made from FDM show anisotropic material properties. This paper proposes an analytic model to predict the tensile strength of FDM parts. Applying the Classical Lamination Theory, which was developed for laminated composite materials, a computer code was implemented. Tsai-Wu failure criterion was added to the code to predict the failure of the FDM parts. The tensile strengths predicted by the analytic model were compared with experimental data. The data and prediction agreed reasonably well to prove the validity of the model. In addition, a web-based advisory service was developed to provide to strength prediction and design rules for FDM parts.