• Structural Engineering and Mechanics
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• 제58권3호
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• pp.475-514
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• 2016

Various models have been proposed by several researchers for predicting the exterior RC beam-column joint shear strength. Most of these models were calibrated and verified with some limited experimental database. From the models it has been identified that the joint shear strength majorly depends on ten governing parameters. In the present paper, detailed investigation of twelve analytical models for predicting shear strength of exterior beam-column joint has been carried out. The study shows the effect of each governing parameter on joint shear strength predicted by various models. It has been observed that the consensus on effect of few of the governing parameters amongst the considered analytical models has not been attained. Moreover, the predicted joint strength by different models varies significantly. Further, the prediction of joint shear strength by these analytical models has also been compared with a set of 200 experimental results from the literature. It has been observed that none of the twelve models are capable of predicting joint shear strength with sufficient accuracy for the complete range of experimental results. The research community has to reconsider the effect of each parameters based on larger set of test results and new improved analytical models should be proposed.

• Coupled systems mechanics
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• 제12권6호
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• pp.539-555
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• 2023

Although some prediction models have successfully developed for ultra-high performance concrete (UHPC), they do not provide insights and explicit relations between all constituents and its consistency, and compressive strength. In the present study, based on the experimental results, several mathematical models have been evaluated to predict the consistency and the 28-day compressive strength of UHPC. The models used were Linear, Logarithmic, Inverse, Power, Compound, Quadratic, Cubic, Mixed, Sinusoidal and Cosine equations. The applicability and accuracy of these models were investigated using experimental data, which were collected from literature. The comparisons between the models and the experimental results confirm that the majority of models give acceptable prediction with a high accuracy and trivial error rates, except Linear, Mixed, Sinusoidal and Cosine equations. The assessment of the models using numerical methods revealed that the Quadratic and Inverse equations based models provide the highest predictability of the compressive strength at 28 days and consistency, respectively. Hence, they can be used as a reliable tool in mixture design of the UHPC.

• 생물정신의학
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• 제6권2호
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• pp.161-169
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• 1999

There are a number of approaches in developing experimental models for depression, but there is no such thing as a best model for depressive syndrome. Animal models are subject to the obvious limitations inherent in the assumption that human psychopathology can be represented accurately in lower animals. Recently, the concern increasingly is to develop a variety of experimental paradigms in animals to study selected aspects of human psychopathology, and animal models should be understood as basically experimental preparations that are developed to carry out these objects. Therefore, a battery of a variety of animal models should be applied to permit detailed pathophysiological studies and to develop new antidepressant treatments. Animal models of depression basically consider behavioral isomorphism with the human depression a plus, but not a req-uirement, and the model behavior should be defined operationally in order to be reproduced reliably by other researchers and be responsive to those agents possessing demonstrated clinical efficacy in human depression. In conclusion, animal models of depression have played a significant role in elucidating pathophysiology of depression and developing current treatments for depression, but there is no single comprehensive model for depression until now. Each of the proposed animal model has its advantages and limitations. In other words, certain paradigms are suitable for studying certain phenomena, whereas others are more suitable for studying other aspects. The best model for depression depends upon what the question is.

• 전기학회논문지
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• 제65권4호
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• pp.642-651
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• 2016

For the acceleration and brake systems of an autonomous vehicle, the dynamic models from acceleration (brake) pedal input to driving(braking) torque at the vehicle wheel are represented by a set of linear transfer functions in this paper. We present an experimental method that can identify these models using a single rectangular pulse response data. Various magnitude of inputs with different running speeds are applied to experimental tests. All the identified models are demonstrated by the measured data. Both acceleration and brake models have been also validated by comparing the velocity of a full vehicle model associated with the proposed models with the measured vehicle velocity.

• Earthquakes and Structures
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• 제14권6호
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• pp.551-565
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• 2018

Experimental testing is considered the most realistic approach to obtain a detailed representation of the nonlinear behaviour of masonry-infilled reinforced concrete (RC) structures. Among other applications, these tests can be used to calibrate the properties of numerical models such as simplified macro-models (e.g., strut-type models) representing the masonry infill behaviour. Since the significant cost of experimental tests limits their widespread use, alternative approaches need to be established to obtain adequate data to validate the referred simplified models. The proposed paper introduces a detailed finite element modelling strategy that can be used as an alternative to experimental tests to represent the behaviour of masonry-infilled RC frames under earthquake loading. Several examples of RC infilled frames with different infill configurations and properties subjected to cyclic loading are analysed using the proposed modelling approach. The comparison between numerical and experimental results shows that the numerical models capture the overall nonlinear behaviour of the physical specimens with adequate accuracy, predicting their monotonic stiffness, strength and several failure mechanisms.

• 한국분무공학회지
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• 제5권2호
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• pp.35-42
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• 2000

A number of atomization and droplet breakup models have been developed and used to predict the diesel spray characteristics. Of the many atomization and droplet breakup models based on the breakup mechanism due to aerodynamic liquid and gas interaction, four models classified as mathematical models, such as TAB, modified TAB, DDB, WB and one of the hybrid model based on WB and TAB models were selected for the assessment of prediction ability of diesel spray dynamics. The assessment of these models by using KIVA-II code was performed by comparing with the experimental data of spray tip penetration and sauter mean diameter(SMD) from the literature. It is found that the prediction of spray tip penetration and SMD by the hybrid model was only influenced by the initial parcel number. All the atomization and droplet breakup models considered here was strongly dependent on the grid resolution. Therefore it is important to check the grid resolution to get an acceptable results in selecting the models. At low injection pressure, modified TAB model could only give the good agreement with experimental data of spray tip penetration and both of modified TAB and DDB models were recommendable for the prediction of SMD. At high injection pressure, hybrid model could only give the good agreement with the experimental data of spray tip penetration and the prediction of all of the selected models did not match the experimental data. Spray tip penetration was increased with the increase the $B_1$ and the increase of $B_1$ did not affected the prediction of SMD.

• 디지털융복합연구
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• 제12권8호
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• pp.423-430
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• 2014

본 연구의 목적은 뇌졸중 동물 실험 모델에서 환경 강화는 기능 회복을 향상 시키고 이로 인하여 뇌에 형태학적, 생화학과 행동에서 특징적인 변화와 그 효과들을 소개하고, 뇌졸중 환자에 환경 강화의 적용은 재활치료 및 작업치료를 포함한 다양 치료와 전 임상 실험의 중요성을 설명하고자 한다. 이 종설 논문에서는 주로 뇌졸중 동물 실험 모델에서 환경 강화로 인한 기능적 회복에 대한 효과와 신경 친화성 물질, 특정 단백질의 발현 및 임상 적용 사례 등의 연구 결과들을 소개하였다. 마지막으로 임상에서 뇌졸중 환자에게 환경 강화의 적용 가능성과 작업치료 및 재활치료의 관점에서 설명하였다.

• Computers and Concrete
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• 제19권6호
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• pp.717-724
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• 2017

In this paper, four formulas are proposed via gene expression programming (GEP)-based models and regression analysis (RA) to predict the flexural strength ($f_s$) values of mortars containing different mineral admixtures that are ground granulated blast-furnace slag (GGBFS), silica fume (SF) and fly ash (FA) at different ages. Three formulas obtained from the GEP-I, GEP-II and GEP-III models are constituted to predict the $f_s$ values from the age of specimen, water-binder ratio and compressive strength. Besides, one formula obtained from the RA is constituted to predict the $f_s$ values from the compressive strength. To achieve these formulas in the GEP and RA models, 972 data of the experimental studies presented with mortar mixtures were gathered from the literatures. 734 data of the experimental studies are divided without pre-planned for these formulas achieved from the training and testing sets of GEP and RA models. Beside, these formulas are validated with 238 data of experimental studies un-employed in training and testing sets. The $f_s$ results obtained from the training, testing and validation sets of these formulas are compared with the results obtained from the experimental studies and the formulas given in the literature for concrete. These comparisons show that the results of the formulas obtained from the GEP and RA models appear to well compatible with the experimental results and find to be very credible according to the results of other formulas.

• Wind and Structures
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• 제25권6호
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• pp.537-549
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• 2017

In this study, the turbulent flow around a bluff body for different wind velocities was investigated numerically by using its two- and three-dimensional models. These models were tested to verify the validity of the simulation by being compared with experimental results which were taken from the literature. Variations of non-dimensional velocities in different positions according to the bluff body height were analysed and illustrated graphically. When the velocity distributions were examined, it was seen that the results of both two- and three-dimensional models agree with the experimental data. It was also seen that the velocities obtained from two-dimensional model matched up with the experimental data from the ground to the top of the bluff body. Particularly, compared to the front part of the bluff body, results of the upper and back part of the bluff body are better. Moreover, after comparing the results from calculations by using different models with experimental data, the effect of multidimensional models on the obtained results have been analysed for different inlet velocities. The calculation results from the two-dimensional (2D) model are in satisfactory agreement with the calculation results of the three-dimensional model (3D) for various flow situations when comparing with the experimental data from the literature even though the 3D model gives better solutions.

• Advances in nano research
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• 제14권5호
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• pp.443-450
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• 2023

Carbon nanotubes (CNTs) have received increased interest in reinforcing research for polymer matrix composites due to their exceptional mechanical characteristics. Its high surface area/volume ratio and aspect ratio enable polymer-based composites to make the most of its features. This study focuses on the experimental tensile testing and fabrication of carbon nanotube reinforced composite (CNTRC) beams, exploring various micromechanical models. By examining the performance of these models alongside experimental results, the research aims to better understand and optimize the mechanical properties of CNTRC materials. Tensile properties of neat epoxy and 0.3%; 0.4% and 0.5% by CNT reinforced laminated single layer (0°/90°) carbon fiber composite beams were investigated. The composite plates were produced in accordance with ASTM D7264 standard. The tensile test was performed in order to see the mechanical properties of the composite beams. The results showed that the optimum amount of CNT was 0.3% based on the tensile capacity. The capacity was significantly reduced when 0.4% CNT was utilized. Moreover, the experimental results are compared with Finite Element Models using ABAQUS. Hashin Failure Criteria was utilized to predict the tensile capacity. Good conformance was observed between experimental and numerical models. More importantly is that Young' Moduli of the specimens is compared with the prediction Halpin-Tsai and Mixture-Rule. Although Halpin-Tsai can accurately predict the Young's Moduli of the specimens, the accuracy of Mixture-Rule was significantly low.