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چكيده انگليسي :

Calculation of Bending Rigidity of Fabric Using a Fixed Pinned Elastic Beam System Mahla Hedayati m hedayati@tx iut ac ir Date of Submission 2011 31 5 Department of Textile Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiDr Mohammad Ghane m ghane@cc iut ac irDr S Abdolkarim Hosseini hosiniir@cc iut ac irAbstract Different methods with different principles were used to measure the bending rigidity of fabrics andyarns which report different bending rigidity One of the most common methods is PIERCE method inwhich the distortion of the end of samples in the experiments causes errors and inaccuracy In this study a method was proposed to measure bending modulus of fabric A movable jaw was used toprovide supports for the deflection of fabric One end of the fabric was fixed on a support while the otherend of the fabric was placed on a simple support to avoid the distortion error of the end of the fabric And thefabric was bent under its own weight The set was placed afront of digital camera The picture of the bentfabric was captured from five different support distances and saved The picture was processed in an imageprocessing program and the maximum deflection coordination and the shape of bending curve of fabric wasautomatically obtained The small deflection equations were then used to calculate the bending rigidity andthe bending modulus of the fabrics In order to verification of the result large deflection equation were alsoused The fabric was modeled in ABAQUS software and the theoretical shapes of the deflected fabric insmall and large deflections was obtained Also the bending modulus and the bending rigidity of the sampleswere calculated by Pierce method The comparison of the experimental and theoretical curves showed that curves were reasonably closed toeach other in all five support distances Of course difference between bending curve in small deflections andlarge deflections increased with increasing support distances This indicates that the deflections were close tolarge deflections and so it causes inaccuracy in small deflections equations But these differences even inthe maximum support distances is insignificant So it can be concluded that small deflection equations can beused to calculate the bending modulus and bending rigidity of the fabric with an acceptably accuracy Furthermore the comparison of the obtained results of the fixed pinned elastic beam system in this studywith results of Pierce method showed that the bending rigidity from fixed pinned elastic beam system aregreater than the values from Pierce method The difference may be explained by Hung s bilinear theory ofthe moment curvature relation The curvature of bent fabric in the case of fixed pinned elastic beam systemunder its own weight is lower and closer to the first linear part of the Hung s model whereas the curvature inthe case of Pierce method is higher and closer to the second part and consequently provides less bendingrigidity The result also revealed that there was high correlation between obtained bending rigidity of Piercemethod and mentioned method in this study So fixed pinned elastic beam system can be used to calculatethe bending rigidity of the fabric with an acceptably accuracy Key Words Bending rigidity of fabric Image processing Small deflection Large deflection ABAQUSsoftware

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محاسبه ي سختي خمشي پارچه با استفاده از سيستم تير الاستيك با تكيه گاه هاي ساده- گيردار

پردازش تصوير , تغيير شكل هاي كوچك , تغيير شكل هاي بزرگ , نرم افزار ABAQUS