• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.11
• /
• pp.1516-1523
• /
• 2004

The purpose of this study were to analyze the effect of weft knit structural characteristics on the subjective texture and sensibility. For this, the material was knitted into 8 kinds of weft plain knit fabrics with four kinds of fiber components such as wool, acryl, rayon, and nylon, 3 steps of densities and 3 steps of twist numbers to ply two yarns. The data were analyzed by factor analysis, ANOVA and multidimensional scaling. From factor analysis, subjective textures were categorized as 'bulk/resilience', 'surface/density' and 'soft/drape', and subjective sensibilities were categorized as 'natural/comfortable', 'feminine/elegance' and 'stable/neat' Among the knit structural characteristics, the component of fibers and the density of fabrics were the important factors to give variations in texture and sensibility : In comparison with wool knit of medium density, the knit fabrics of other components and different densities each showed a unique texture and sensibility. But twist number to ply two yams had a few influence on subjective properties. As a result of MDS analysis, the texture and sensibility of plain weft knit fabrics was classified as 'thin-full', 'hard-soft', 'young-old' and 'warm-cool'.

• Journal of the Society of Disaster Information
• /
• v.12 no.4
• /
• pp.432-439
• /
• 2016

To make a model of a Impact/Blast resistant composite material and perform the analysis, material properties of the composite material are required. In order to obtain such a property value, it is necessary to input the result obtained by performing a lot of material tests by the calculation formula of the situation, and there is a lot of difficulty in the case of a special purpose material which is not a general material. In this study, modeling and structural analysis of composite fiber panels for protection and explosion - proofing were performed in ACP(ANSYS Composite PrePost) and AUTODYN by applying the application properties of composites provided in Ansys Workbench environment.

• Computers and Concrete
• /
• v.12 no.4
• /
• pp.413-429
• /
• 2013

The primary aim of this study is to develop a three dimensional finite element (FE) model to predict the axial stress-strain relationship and ultimate strength of the FRP-wrapped UHPC columns by comparing experimental results. The reliability of four selected confinement models and three design codes such as ACI-440, CSA-S806-02, and ISIS CANADA is also evaluated in terms of agreement with the experimental results. Totally 6 unconfined and 36 different types of the FRP-wrapped UHPC columns are tested under monotonic axial compression. The values of ultimate strengths of FRP-wrapped UHPC columns obtained from the experimental results are compared and verified with finite element (FE) analysis results and the design codes mentioned above. The concrete damage plasticity model (CDPM) in Abaqus is utilized to represent the confined behavior of the UHPC. The results indicate that agreement between the test results and the non-linear FE analysis results is highly satisfactory. The CSA-S806-02 design code is considered more reliable than the ACI-440 and the ISIS CANADA design codes to calculate the ultimate strength of the FRP-wrapped UHPC columns. None of the selected confinement models that are developed for FRP-wrapped low and normal strength concrete columns can safely predict the ultimate strength of FRP-wrapped UHPC columns.

• Computers and Concrete
• /
• v.20 no.1
• /
• pp.31-38
• /
• 2017

In the present study an Artificial Neural Network (ANN) was used to predict the compressive strength of self-compacting concrete. The data developed experimentally for self-compacting concrete and the data sets of a total of 99 concrete samples were used in this work. ANN's are considered as nonlinear statistical data modeling tools where complex relationships between inputs and outputs are modeled or patterns are found. In the present ANN model, eight input parameters are used to predict the compressive strength of self-compacting of concrete. These include varying amounts of cement, coarse aggregate, fine aggregate, fly ash, fiber, water, super plasticizer (SP), viscosity modifying admixture (VMA) while the single output parameter is the compressive strength of concrete. The importance of different input parameters for predicting the strengths at various ages using neural network was discussed in the study. There is a perfect correlation between the experimental and prediction of the compressive strength of SCC based on ANN with very low root mean square errors. Also, the efficiency of ANN model is better compared to the multivariable regression analysis (MRA). Hence it can be concluded that the ANN model has more potential compared to MRA model in developing an optimum mix proportion for predicting the compressive strength of concrete without much loss of material and time.

• Journal of the Korean Applied Science and Technology
• /
• v.28 no.3
• /
• pp.290-298
• /
• 2011

Natural Omija belongs to magnoliaceae was known to possess natural odor, taste, color, and various pharmaceutical & chemical characteristics. Omija extraction was extracted using ethanol as a solvent. Omija extract showed a light red-violet color of viscous liquid state. Some conclusions from the result of characteristic experiment were obtained as follows. From the result of antimicrobial experiment, occurrence of staphylococuss aureus and aspergillus niger as microbes was decreased according to the passage of time. This phenomenon could know that Omija component is affected to antimicrobial effect. From the result of dye experiment, fiber dyeing showed with some ivory color after dyed to cotton and silk. This phenomenon could know that Omija component is affected to dyeing effect from observation of scanning electron microscope(SEM). From the result of instrument analysis, inorganic components of K(107.30ppm), Na(2.110ppm), Ca(0.935ppm), Mg(0.891ppm), Li(0.270ppm) etcs from Omija were detected with ICP/OES, and aromatic components of benzene(10.808), a-pinene(13.996), phenol(14.183), ${\beta}$-terpene(15.840), a-terpinolene(17.616) etcs from Omija were also detected with GC/MSD.

• Biomedical Science Letters
• /
• v.8 no.1
• /
• pp.21-27
• /
• 2002

To investigate an effect of bum on the cardiac function, we studied some biochemical assay, ultrastructural changes and stereological analysis in heart tissue. Sprague-Dawley rats were induced a 15% total body surface area scald burn. 5 and 24 hours later, the heart was excised. Burned rats showed the decrease of heart weight per body weight (%) compared with control. The activity of serum aspartate aminotransferase was significantly increased at 5 (p＜0.001) and 24 hours (p＜0.01) after burn compared with control. And the activity of serum LDH was decreased at 5 hours after burn but increased at 24 hours compared with control. Ultrastructurally, enlargement of interstitium and destruction of sarcolemma were observed at 5 and 24 hours after burn. Especially at 5 hours postburn, hypercontraction band was noted and at 24 hours, wavy fiber and muscle fraying were noted. In stereological changes, volume density of mitochondria and myofibril was significantly decreased at postburn 5 and 24 hours. But volume density of sarcoplasmic reticulum was significantly increased at postburn 5 hours. Our data suggest that dermal scald bum causes myocardial dysfunction.

• Textile Coloration and Finishing
• /
• v.26 no.4
• /
• pp.339-346
• /
• 2014

To give a positive effect on dispersion behavior of high performance fibers $Vectran^{(R)}$ in water with reference to wet-laid nonwoven technology, 9 kinds of sulfonate type anionic surfactants were chosen to study. After dispersion experiment, the number and the area occupied by fibers in each sample were counted and figured to calculate the index of dispersion in conjunction with quadrat analysis. Similar tendency was observed in the results of two experiments. The sample without addition of any surfactant resulted in the most aggregated dispersion behavior. As the length of alkyl group attached to sulfonate increases, the sample shows more dispersed behavior. The sample with the surfactant having the aryl group and the longer alkyl group shows the most dispersed behavior and it can be seen with the naked eye as well.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.2 no.2
• /
• pp.1-6
• /
• 2011

This study aims at predicting structural behaviors of RC (Reinforced Concrete) beams retrofitted with hybrid FRPs (Fiber Reinforced Polymers). Toward this goal, structural analysis for the RC beams retrofitted with hybrid FRPs are performed and validated using existing experimental data. For the analysis, failure models due to debonding of FRPs and concrete separation are implemented within FE (Finite Element) model, based on Smith and Teng, model, and Teng and Yao model, respectively. Nonlinear material and geometrical effects are also included in the analysis. The suggested modeling approaches are able to predict structural behaviors of RC beams retrofitted with hybrid FRPs similar to the experimental data, however, a numerical model needs to be developed in order to predict failure strength of RC beams retrofitted with hybrid FRPs accurately.

• Transactions of Materials Processing
• /
• v.29 no.5
• /
• pp.265-271
• /
• 2020

The purpose of this paper is to analyze the numerical simulation accuracy according to the CFRP modeling method in the CFRP-Al alloy SPR (Self-Piercing Rivet) joint process. The mechanical properties of the CFRP, aluminum sheet are precisely obtained from the tensile test according to the loading direction. Additionally, the hardening curve of rivet was calculated from the inverse analysis of the machined rivet-ring compression test. For the CFRP-Al alloy SPR simulation, two kinds of the CFRP modeling methods were established based on the continuum and layer-by-layer approaches. The simulation results showed that the CFRP layer-by-layer modeling method can provide more reliable prediction shape of the fractured sheets and deformed rivet. This simulation technique can be used in evaluating the CFRP-Metal SPR performance and designing the SPR process conditions.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.5
• /
• pp.758-769
• /
• 1986

A general analytical procedure is developed for evaluating the free vibration characteristics of orthotropic and laminated composite circular cylindrical shells. The solution is obtained through a direct solution procedure with axial mode displacements presented as simple Fourier series expressions. On the basis of the various thin shell theories most commonly used, the frequency equation is derived and is expressed in a unified form. The present analysis can deal with shells which are made of an arbitrary number of bonded layers each with a different thickness and different elastic orthotropic properties, and have classical boundary conditions of any kind. Several examples are shown with the consideration of the effects of fiber orientations and boundary conditions as well as different shell geometries and material properties. To verify the validity and accuracy of this analysis, the results are compared with the experimental and analytical results of other workers. Agreement among the various results is found to be fairly good.