• Title/Summary/Keyword: structural parameters

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Effect of Fabric Structural Parameters and Surface Finishing Characteristics to Water Repellency/Proofing/Vapor Permeability of Breathable Fabrics for Sportswear Clothing (직물 구조인자와 표면 가공특성이 스포츠 의류용 투습직물의 발수/방수/투습특성에 미치는 영향)

  • Kim, Hyun Ah
    • Fashion & Textile Research Journal
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    • v.22 no.1
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    • pp.112-118
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    • 2020
  • This paper examined the water repellency, water proofing and water vapor permeability of twelve types of woven fabrics for sports wear clothing. Their physical properties were compared and discussed with the fabric structural parameters and surface finishing effect. A water repellent property of 100% was obtained in the coated or laminated water repellent finished fabrics; in addition, cotton/nylon breathable composite fabrics treated with a laminated finishing and with low fabric density showed a 90% water repellency. Water proofing fabric above 6,000 mm H2O hydraulic pressure was achieved by coated or laminated finishing; however, high density fabric or medium-level coated fabrics exhibited 100% water repellent and low water proofing characteristics. Superior water vapor permeability characteristics with good water repellency and proofing properties were achieved at the 2.5 layered low density and with 0.7 - 0.9 cover factor nylon fabrics treated with hydrophilic laminated finishing. The regression analysis for examining the effects of fabric structural parameters and surface finishing such as coating and laminating to the water vapor permeability exhibited a high determination coefficient of fabric structural parameters of 63.5%; in addition,, main factors among fabric structural parameters appeared to be cover factor and fabric thickness per weight. Coating and Laminating factors exhibited determination coefficient of water vapor permeability parameters of 36.5%.

Identification of Structural Parameters from Frequency Response Functions (주파수 응답함수를 이용한 구조 파라메터 예측)

  • Kim, Kyu-Sik;Kang, Yeon-June
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.863-869
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    • 2007
  • An improved method based on a normal frequency response function (FRF) is proposed to identify structural parameters such as mass, stiffness and damping matrices directly from the FRFs of a linear mechanical system. The method for estimating structural parameters directly from the measured FRFs of a structure is presented. This paper demonstrates that the characteristic matrices are extracted more accurately by using a weighted equation and eliminating the matrix inverse operation. The method is verified for a four degree-of-freedom lumped parameter system and an eight degree-of-freedom finite element beam. Experimental verification is also performed for a free-free steel beam whose size and physical properties are the same as those of the finite element beam. The results show that the structural parameters, especially the damping matrix, can be estimated more accurately by the proposed method.

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Posterior density estimation for structural parameters using improved differential evolution adaptive Metropolis algorithm

  • Zhou, Jin;Mita, Akira;Mei, Liu
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.735-749
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    • 2015
  • The major difficulty of using Bayesian probabilistic inference for system identification is to obtain the posterior probability density of parameters conditioned by the measured response. The posterior density of structural parameters indicates how plausible each model is when considering the uncertainty of prediction errors. The Markov chain Monte Carlo (MCMC) method is a widespread medium for posterior inference but its convergence is often slow. The differential evolution adaptive Metropolis-Hasting (DREAM) algorithm boasts a population-based mechanism, which nms multiple different Markov chains simultaneously, and a global optimum exploration ability. This paper proposes an improved differential evolution adaptive Metropolis-Hasting algorithm (IDREAM) strategy to estimate the posterior density of structural parameters. The main benefit of IDREAM is its efficient MCMC simulation through its use of the adaptive Metropolis (AM) method with a mutation strategy for ensuring quick convergence and robust solutions. Its effectiveness was demonstrated in simulations on identifying the structural parameters with limited output data and noise polluted measurements.

Study on Correlation between Mechanical Properties and Processing Shrinkage of Polyester Woven Fabric (폴리에스테르 직물의 공정수축특성과 직물역학특성과의 상관성 연구)

  • 오애경;기승진
    • Textile Science and Engineering
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    • v.30 no.11
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    • pp.803-816
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    • 1993
  • The processing shrinkage has a direct influence on the mechanical properties and the physical properties of fabric. This paper surveys correlation between the mechanical properties and the processing shrinkage of polyester plain woven fabric and a basic study on hand characteristic of New Synthetic Fabrics. The effects of fabric structural parameters on the processing shrinkage. The effects of processing shrinkage and the fabric structural parameters on the mechanical properties and non-linearity analysis between the fabric structural parameters and the mechanical properties were analyzed. This study has been carried out the mechanical properties on polyester fabric in connection with such fabric structural parameters as the fabric warp density, the fabric weft density. the number of weft twist, and the linear density of yarn.

Study on Mechanical Properties of Polyester Woven Fabric (II)- Honlinearity of Shear Properties - (폴리에스테르 직물의 역학특성에 관한 연구(II)-전단 특성의 비선형성-)

  • 오애경;김승진
    • Textile Science and Engineering
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    • v.30 no.10
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    • pp.719-730
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    • 1993
  • The shear behavior of fabrics is an important characteristic in fabrics whose end-use is for apparel purpose. The shear properties of the fabrics influence the draping, pliabiltiy and hand of fabrics. Moreover, the shearing behaviors of fabric have been applied in designing air ship, space suit and inflatable shelters. Therefore shear behavior plays very important role among the various mechanical properties of fabrics. The purpose of this paper is to analyze shear properties of polyester fabric in association with such fabric structural parameters as twist level, fineness, fabric density. Weave structure and processing factors. So far, correlation between shear properties and fabrics structural parameters and processing shrinkage with weave structure is examined. What is more. non-linear correlation between shear properties and fabric structural parameters is analyzed. Finally the regression analysis between processing shrinkage and shear properties and fabric structural parameters is carried on.

Mechanical and Thermal Behavior of Polyamide-6/Clay Nanocomposite Using Continuum-based Micromechanical Modeling

  • Weon, Jong-Il
    • Macromolecular Research
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    • v.17 no.10
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    • pp.797-806
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    • 2009
  • The mechanical and thermal behaviors of polyamide-6/clay nanocomposites were studied using the continuum-based, micromechanical models such as Mori-Tanaka, Halpin-Tsai and shear lag. Mechanic-based model prediction provides a better understanding regarding the dependence of the nanocomposites' reinforcement efficiency on conventional filler structural parameters such as filler aspect ratio ($\alpha$), filler orientation (S), filler weight fraction (${\Psi}_f$), and filler/matrix stiffness ratio ($E_f/E_m$). For an intercalated and exfoliated nanocomposite, an effective, filler-based, micromechanical model that includes effective filler structural parameters, the number of platelets per stack (n) and the silicate inter-layer spacing ($d_{001}$), is proposed to describe the mesoscopic intercalated filler and the nanoscopic exfoliated filler. The proposed model nicely captures the experimental modulus behaviors for both intercalated and exfoliated nanocomposites. In addition, the model prediction of the heat distortion temperature is examined for nanocomposites with different filler aspect ratio. The predicted heat distortion temperature appears to be reasonable compared to the heat distortion temperature obtained by experimental tests. Based on both the experimental results and model prediction, the reinforcement efficiency and heat resistance of the polyamide-6/clay nanocomposites definitely depend on both conventional (${\alpha},\;S,\;{\Psi}_f,\;E_f/E_m$) and effective (n, $d_{001}$) filler structural parameters.

Probabilistic damage detection of structures with uncertainties under unknown excitations based on Parametric Kalman filter with unknown Input

  • Liu, Lijun;Su, Han;Lei, Ying
    • Structural Engineering and Mechanics
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    • v.63 no.6
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    • pp.779-788
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    • 2017
  • System identification and damage detection for structural health monitoring have received considerable attention. Various time domain analysis methodologies based on measured vibration data of structures have been proposed. Among them, recursive least-squares estimation of structural parameters which is also known as parametric Kalman filter (PKF) approach has been studied. However, the conventional PKF requires that all the external excitations (inputs) be available. On the other hand, structural uncertainties are inevitable for civil infrastructures, it is necessary to develop approaches for probabilistic damage detection of structures. In this paper, a parametric Kalman filter with unknown inputs (PKF-UI) is proposed for the simultaneous identification of structural parameters and the unmeasured external inputs. Analytical recursive formulations of the proposed PKF-UI are derived based on the conventional PKF. Two scenarios of linear observation equations and nonlinear observation equations are discussed, respectively. Such a straightforward derivation of PKF-UI is not available in the literature. Then, the proposed PKF-UI is utilized for probabilistic damage detection of structures by considering the uncertainties of structural parameters. Structural damage index and the damage probability are derived from the statistical values of the identified structural parameters of intact and damaged structure. Some numerical examples are used to validate the proposed method.

Integration of health monitoring and vibration control for smart building structures with time-varying structural parameters and unknown excitations

  • Xu, Y.L.;Huang, Q.;Xia, Y.;Liu, H.J.
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.807-830
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    • 2015
  • When a building structure requires both health monitoring system and vibration control system, integrating the two systems together will be cost-effective and beneficial for creating a smart building structure with its own sensors (nervous system), processors (brain system), and actuators (muscular system). This paper presents a real-time integrated procedure to demonstrate how health monitoring and vibration control can be integrated in real time to accurately identify time-varying structural parameters and unknown excitations on one hand, and to optimally mitigate excessive vibration of the building structure on the other hand. The basic equations for the identification of time-varying structural parameters and unknown excitations of a semi-active damper-controlled building structure are first presented. The basic equations for semi-active vibration control of the building structure with time-varying structural parameters and unknown excitations are then put forward. The numerical algorithm is finally followed to show how the identification and the control can be performed simultaneously. The results from the numerical investigation of an example building demonstrate that the proposed method is feasible and accurate.

An Implementation of Classification Method of Osteoporosis using CT images (CT 영상을 이용한 골다공증 분류 방법의 구현)

  • Jung, Sung-Tae
    • Journal of Korea Multimedia Society
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    • v.19 no.1
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    • pp.1-9
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    • 2016
  • In this paper, we propose a method of measuring bone mineral density in a peripheral-type clinical X-ray CT using a phantom, and we propose a method of classifying osteoporosis using bone mineral density and bone structure parameters together. It segments the trabecular bone region and cortical bone region for the six sections of the phantom and calculates the average HU value of the segmented regions. By using these values, it derives an expression converting HU value to bone mineral density. It segments trabecular bone of 1 cm region in the end part of distal radius and extracts the bone mineral density and structural parameters for the trabecular bone region. We extracted bone mineral density and structural parameters for the 18 subjects each of normal and osteoporotic group. We carried out classification experiments using three classification methods; SAD, SVM, ANN. The sensitivity, specificity, accuracy, positive predictive value, negative predictive value, likelihood ratio of the classification was improved in the order of ANN, SVM and SAD. Also, The sensitivity, specificity, accuracy, positive predictive value, negative predictive value, likelihood ratio of the classification was improved when we use the bone mineral density and structural parameters together.

A Study on the Fitness of Fusible Interlining to the Thin Worsted Fabrics with Various Structural Parameters (직물 접착심지의 얇은 소모직물에 대한 적합성에 관한 연구)

  • 김승진;하지현
    • Textile Science and Engineering
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    • v.33 no.2
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    • pp.150-155
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    • 1996
  • Functions of fusible interlinings to the top fabric are to enhance the formability for a beautiful silhouette and elastic potential to the deformed fabric under the bending and shearing deformations during wearing, which decide appearance and wearing properties of the garment. The objective of this study is to analyse fitness of fusible interlining to the thin worsted fabric with various structural parameters. For the purpose of this objective, specimens with various weft yarn twists and weft densities of thin worsted fabric are prepared for 3 harness fabrics. Three fusible interlinings which are made by cotton 100%, cotton 43%/viscose rayon 57% and PET 30%/viscose rayon 70% are used for adhering to thin worsted fabrics. Mechanical properties of these thirty adhesive fabrics fused with these interlinings are measured by KES-FB System for analysing appearance and wearing properties of garment state and for examining the fitness of fusible interlining to the thin worsted fabrics with various fabric structural parameters. Same procedures are performed under repetition of dry cleaning of adhesive fabrics for analysing relationship between repetition of dry cleaning and fitness of fusible interlining to the various thin worsted fabrics.