• Coupled systems mechanics
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• 제8권1호
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• pp.1-17
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• 2019

The present paper deals with delamination fracture analyses of the multilayered functionally graded non-linear elastic Symmetric Split Beam (SSB) configurations. The material is functionally graded in both width and height directions in each layer. It is assumed that the material properties are distributed non-symmetrically with respect to the centroidal axes of the beam cross-section. Sine laws are used to describe the continuous variation of the material properties in the cross-sections of the layers. The delamination fracture is analyzed in terms of the strain energy release rate by considering the balance of the energy. A comparison with the J-integral is performed for verification. The solution derived is used for parametric analyses of the delamination fracture behavior of the multilayered functionally graded SSB in order to evaluate the effects of the sine gradients of the three material properties in the width and height directions of the layers and the location of the crack along the beam width on the strain energy release rate. The solution obtained is valid for two-dimensional functionally graded non-linear elastic SSB configurations which are made of an arbitrary number of lengthwise vertical layers. A delamination crack is located arbitrary between layers. Thus, the two crack arms have different widths. Besides, the layers have individual widths and material properties.

• 한국의류학회지
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• 제26권1호
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• pp.152-159
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• 2002

Neural networks are used to predict the sense of touch of polyurethane coated fabrics. In this study, we used the multi layer perceptron (MLP) neural networks in Neural Connection. The learning algorithm for neural networks is back-propagation algorithm. We used 29 polyurethane coated fabrics to train the neural networks and 4 samples to test the neural networks. Input variables are 17 mechanical properties measured with KES-FB system, and output variable is the sense of touch of polyurethane coated fabrics. The influence of MLF function, the number of hidden layers, and the number of hidden nodes on the prediction accuracy is investigated. The results were as follows: MLP function, the number of hidden layer and the number of hidden nodes have some influence on the prediction accuracy. In this work, tangent function, the architecture of the double hidden layers and the 24-12-hidden nodes has the best prediction accuracy with the lowest RMS error. Using the neural networks to predict the sense of touch of polyurethane coated fabrics has hotter prediction accuracy than regression approach used in our previous study.

• Tribology and Lubricants
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• 제31권3호
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• pp.86-94
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• 2015

We perform lacquer formation experiments with various combinations of marine fuel oils and lubricant oils. We also investigate the influences of base number (BN) in lubricant oil and sulfur content in fuel oil. A dissolution test with 10% dilute sulfuric acid and pull-off force test are accomplished to distinguish whether the residual layers are lacquering or not. The lacquering layers are dissolved by dilute sulfuric acid and have a strong pull-off force. Moreover, the calcium content detected in the residual layers is compared by energy dispersive x-ray spectroscopy (EDS). More calcium is detected in the lacquer layers than in other residual layers. Distillate fuels containing low sulfur levels are more prone to lacquering when mixed with lubricant oil with a high BN. On the other hand, residual fuels with a high sulfur content do not form lacquer. We investigate the effect of mixture volume ratio. The mixture with higher fuel oil content is more prone to generate lacquer. These experiments indicate that a lubricant with an appropriate BN should be used to prevent lacquer forming on the surfaces such as cylinder liners depending on the sulfur content of fuel oil.

• Structural Engineering and Mechanics
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• 제24권4호
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• pp.479-491
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• 2006

This paper deals with optimal fibre orientations of symmetrically laminated fibre reinforced composite structures for maximising the fundamental frequency of small-amplitude. A set of fiber orientation angles in the layers are considered as design variable. The Modified Feasible Direction method is used in order to obtain the optimal designs. The effects of number of layers, boundary conditions, laminate thicknesses, aspect ratios and in-plane loads on the optimal designs are studied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.136-138
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• 2005

Merocyanine dye (MD) has been extensively investigated due to its marked potential application to photo-electric devices. We fabricated the number of layers to control its optical characteristics using the Langmuir-Blodgett (LB) method. We evaluated the morphology and optical characteristics of MD LB films using Atomic Force Microscopy (AFM) and UV spectroscopy, PL spectroscopy. As a result, we obtained the quantitative morphology and optical characteristics of LB films from controlling the deposided layers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1744-1746
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• 1999

In this paper, we give pressure stimulation into organic ultra thin films and detected the induced displacement current properties, and then manufacture a device under the accumulation condition. In processing of a device manufacture, we can see the process is good from the change of a surface pressure and transfer ratio of area per molecule of organic ultra thin films. The structure of manufactured device is MIM(Au/polyimide LB films/AU), the number of accumulated 19 layers. I-V characteristic of the device is measured from -5[V] to +5[V]. The maximum value of measured current is increased as the number of accumulated layers are decreased. The insulation of a thin film is better as the interval between electrodes is larger, and the insulation properties of a thin film is better as the distance between electrodes is larger.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.807-809
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• 1998

We give pressure stimulation into organic thin films and detect the induced displacement current, In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/organic thin films(Kapton-Polyimide)/Au and I-V properties of the device is measured from 0(V) to +5(V). The maximum value of measured current is increased as the number of accumulated layers are decreased. The resistance for the number of accumulated layers, the energy density for an input voltage show desired results.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.130-131
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• 2018

The compressive strength of concrete is determined by various influencing factors. However, the conventional method for estimating the compressive strength of concrete has been suggested by considering only 1 to 3 specific influential factors as variables. In this study, nine influential factors (W/B ratio, Water, Cement, Aggregate(Coarse, Fine), Fly ash, Blast furnace slag, Curing temperature, and humidity) of papers opened for 10 years were collected at 4 conferences in order to know the various correlations among data and the tendency of data. The selected mixture and compressive strength data were learned using the Deep Learning Algorithm to derive an estimated function model. The purpose of this study is to investigate the effect of the number of hidden layers on the prediction performance in the process of estimating the compressive strength for an arbitrary combination.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 춘계학술대회 학술발표 논문집
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• pp.114-117
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• 2000

In this paper, Fuzzy Self-organizing Neural Networks(FSONN) based on Fuzzy Neural Networks(FNN) is proposed to overcome some problems, such as the conflict between ovefitting and good generation, and low reliability. The proposed FSONN consists of FNN and SONN. Here, FNN is used as the premise part of FSONN and SONN is the consequnt part of FSONN. The FUN plays the preceding role of FSONN. For the fuzzy reasoning and learning method in FNN, Simplified fuzzy reasoning and backpropagation learning rule are utilized. The number of layers and the number of nodes in each layers of SONN that is based on the GMDH method are not predetermined, unlike in the case of the popular multi layer perceptron structure and can be generated. Also the partial descriptions of nodes can use various forms such as linear, modified quadratic, cubic, high-order polynomial and so on. In this paper, the optimal design procedure of the proposed FSONN is shown in each step and performance index related to approximation and generalization capabilities of model is evaluated and also discussed.

• Structural Engineering and Mechanics
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• 제66권4호
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• pp.439-444
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• 2018

This paper presents a numerical study on the behavior of continuous hollow steel beam strengthened using carbon fiber reinforced polymers (CFRP). Most previous studies on the CFRP strengthening of steel beams have been carried out on the steel beams with simple boundary conditions. No independent study, to the researcher's knowledge, has studied on the CFRP strengthening of square hollow section (SHS) continuous steel beam. However, this study explored the effect of the use of adhesively bonded CFRP flexible sheets on the behavior of the continuous SHS steel beams. Finite Element Method (FEM) has been employed for modeling. Eleven specimens, ten of which were strengthened using CFRP sheets, were analyzed under different coverage length, the number of layers, and the location of CFRP composite. ANSYS software was used to analyze the SHS steel beams. The results showed that the coverage length, the number of layers, and the location of CFRP composite are effective in increasing the ultimate load capacity of the continuous SHS steel beams. Application of CFRP composite also caused the ductility increase some strengthened specimens.