• 한국주조공학회지
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• 제32권5호
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• pp.225-230
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• 2012

In this study, a more practical and simulation approach which can predict the mechanical properties of aluminum alloys is proposed. First, cooling rate, micro-structure, and mechanical properties of casting product were measured through casting experiment. The relation between cooling rate and SDAS decrease exponentially and the linearly decreasing relation exist between SDAS and mechanical properties. Then, the cooling rate was calculated by casting process simulation and the mechanical properties were predicted by using the relations that were derived through experiment. Experimentally measured mechanical properties and predicted values by simulation were in the range of relatively small difference. The mechanical properties of various Al alloys are expected to be predicted by the casting process simulation before actual casting.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.292-295
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• 2002

In this paper, an analytical model for the prediction of the elastic properties of multi-axial warp knit fabric (MWK) composites is proposed. The geometric limitation, effect of stitching fibers and design parameters of MWK composites are considered in the model. The elastic behavior of MWK composites was conducted by using an averaging method. The predicted elastic properties are in reasonably good agreement with experimental values. Finally the effect of stitching in the MWK composites are discussed.

• 대한기계학회논문집A
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• 제26권11호
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• pp.2399-2408
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• 2002

A prediction procedure has been developed to evaluate the microtructures and material properties of heat affected zone (HAZ) in pressure vessel steel weld, based on temperature analysis, thermodynamics calculation and reaction kinetics model. Temperature distributions in HAE are calculated by finite element method. The microstructures in HAZ are predicted by combining the temperature analysis results with the reaction kinetics model for austenite grain growth and austenite decomposition. Substituting the microstructure prediction results into the previous experimental relations, the mechanical material properties such as hardness, yielding strength and tensile strength are calculated. The prediction procedure is modified and verified by the comparison between the present results and the previous study results for the simulated HAZ in reactor pressure vessel (RPV) circurnferential weld. Finally, the microstructures and mechanical material properties are determined by applying the final procedure to real RPV circumferential weld and the local weak zone in HAZ is evaluated based on the application results.

• Journal of Welding and Joining
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• 제23권4호
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• pp.17-26
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• 2005

HAZ (Heat Affected Zone) which occurs during welding thermal cycle has an important effect on the mechanical properties of the weld metal. So there were many efforts to develop the model which is able to predict the microstructure and mechanical properties in weld HAZ and lots of metallurgical models have reported since early 1940. These models are justifiable based on the reasonable assumption and analytical approach, but they also have limitation by interesting alloying system and assumption in each literature. Therefore, this study summaries the previous models for prediction of properties in weld HAZ. Then several issues to solve for developing the more reliable model were proposed.

• Fibers and Polymers
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• 제6권3호
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• pp.269-276
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• 2005

In this study, cross-cultural comparison of sound sensation for Korean traditional silk fabrics between Korea and America was performed and prediction models for sound sensation by objective measurements including sound parameters such as level pressure of total sound (LPT), Zwicker's psychoacoustic characteristics, and mechanical properties by Kawabata Evaluation System were established for each nation to explore the objective parameters explaining sound sensation of the Korean traditional silk. As results, Koreans felt the silk fabric sounds soft and smooth while Americans were revealed as perceiving them hard and rough. Both Koreans and Americans were pleasant with sounds of Gongdan and Newttong and especially Newttong was preferred more by Americans in terms of sound sensation. In prediction models, some of subjective sensation were found as being related mainly with mechanical properties of traditional silk fabrics such as surface and compressional characteristics.

• Computers and Concrete
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• 제24권5호
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• pp.399-412
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• 2019

In this investigation, Elman neural networks were utilized for predicting the mechanical properties of Self-Compacting Concretes (SCCs). Elman models were designed by using experimental data of many different concrete mixdesigns of various types of SCC that were collected from the literature. In order to investigate the effectiveness of the selected input variables on the network performance in predicting intended properties, utilized data in artificial neural networks were considered in two sets of 8 and 140 input variables. The obtained outcomes showed that not only can the developed Elman ANNs predict the mechanical properties of SCCs with high accuracy, but also for all of the desired outputs, networks with 140 inputs, compared to ones with 8, have a remarkable percent improvement in the obtained prediction results. The prediction accuracy can significantly be improved by using a more complete and accurate set of key factors affecting the desired outputs, as input variables, in the networks, which is leading to more similarity of the predicted results gained from networks to experimental results.

• 감성과학
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• 제14권1호
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• pp.127-136
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• 2011

본 연구에서는 견직물의 색채 특성이 촉감각/감성 이미지에 미치는 영향을 고찰하고 견직물의 역학적 성질과 색채 특성을 이용한 촉감각/감성 이미지 예측모델을 제안하고자 하였다. 연구결과로서 무채색과 유채색 견직물 모두 견직물의 역학적 성질이 기본적으로 촉감각/감성 이미지에 영향을 미치는 것으로 나타났다. 반면에 '매끄럽다', '하늘하늘하다', '독특하다', '두껍다', '뻣뻣하다', '전원적이다', '캐주얼하다', '내추럴하다', '모던하다'는 무채색과 유채색에 따라 유의한 차이가 있었다. 특히 '두껍다'와 '뻣뻣하다'는 견직물이 Red 또는 Green 색상일 때, 그리고 pale 또는 vivid 색조일 때 무채색일 때보다 더 강하게 인지되었고, '전원적이다'와 '캐주얼하다'는 Green 색상의 견직물과 pale 또는 vivid 색조의 견직물에서 무채색 견직물에서보다 더 강하게 느껴지는 경향이어서, 견직물의 색채가 주관적 촉감각/감성에 영향을 줄 수 있음을 시사하였다. 마지막으로 역학적 성질과 색채 특성을 함께 설명변수로 이용한 예측모델을 수립하여 제안하였다.

• 소성∙가공
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• 제32권1호
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• pp.28-34
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• 2023

In this research, a representative volume element (RVE)-based FE Model is presented to estimate the mechanical properties of additively manufactured continuous fiber-reinforced composites with different fiber orientations. To construct the model, an ABAQUS Python script has been implemented to produce matrix and fiber in the desired orientations at the RVE. A script has also been developed to apply the periodic boundary conditions to the RVE. Experimental tests were conducted to validate the numerical models. Tensile specimens with the fiber directions aligned in the 0, 45, and 90 degrees to the loading direction were manufactured using a continuous fiber 3D printer and tensile tests were performed in the three directions. Tensile tests were also simulated using the RVE models. The predicted Young's moduli compared well with the measurements: the Young's modulus prediction accuracy values were 83.73, 97.70, and 92.92 percent for the specimens in the 0, 45, and 90 degrees, respectively. The proposed method with periodic boundary conditions precisely evaluated the elastic properties of additively manufactured continuous fiber-reinforced composites with complex microstructures.

• Composites Research
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• 제32권5호
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• pp.270-278
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• 2019

본 연구에서는 섬유, 기지 및 계면으로 구성된 단방향 복합재료의 대표체적요소를 이용해서 가로방향 기계적 물성을 계면 특성 변화에 따라 예측하고 시험결과에 맞춰 계면의 특성의 보정을 실시하였다. 섬유와 기지로 모델링 된 기존의 대표체적요소는 섬유 길이방향 기계적 물성에 대해 예측 정확도가 높으나 가로방향에 대하여 어느 정도의 편차를 보인다. 따라서, 이런 차이를 보완하기 위해 계면 영역을 도입하였고, 계면의 두께, 탄성 물성과 강도 파라미터에 따라 기계적 물성을 보정하여 복합재료 대표체적요소를 통한 예측의 정확도를 향상시켰다. 그 결과, 복합재료 대표체적요소의 길이방향 물성의 정확도는 유지한 채 가로방향 강성 및 강도의 정확도가 향상됨을 확인하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.111-113
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• 2007

The Mechanical properties of steel in hot strip mill were associated with the alloy composition, plastic deformation, cooling history and so on. In the case of the same alloy composition and deformation conditions, cooling history on ROT (run out table) is the main factor in affecting mechanical properties of steel, especially, in carbon steel. On ROT, the steel undergoes under various kinds of cooling conditions such as radiation, convection by air, water and wetting zone. The coiling temperature (CT) of the steel is also important factor in affecting mechanical properties. But with the same CT, the mechanical properties of steel can be different because the temperature history of cooling is more important factor than CT itself. In this study, we have studied the relations between temperature history and mechanical properties of steel and then the predicted mechanical properties have compared with the measured values.