بررسي اثر ساختاري پارچه دوشاخه حلقوي تاري بر جذب صوت نفوذپذيري نور و هوا

چكيده انگليسي :

76 An investigation into effect of structure of two guide bar warp knitted fabric on acoustic and permeabilies of the fabric Ramin Kalani r kalani2007@yahoo com Date of Submission 2011 10 5 Department of Textile Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor s Name and Email address S Ajeli sajeli@cc iut ac ir M Zarrebini zarrebini@cc iut ac ir Abstract Acoustic phenomenon and sound related pollutions have gained paramount importance as an interested research topic in various scientific fields Elimination and reduction of unwanted sound in buildings and transportation is a serious challenge that has to be faced by designers of these structures Various sound absorbent medium are employed to achieve ever increasing acoustical criteria demanded by health and safety regulations governing various surroundings used by human beings Textile structures have been used as an integral part of noise reduction systems either as structural elements or simultaneously functioning as sound absorber and decorative elements In contrast to the amount research carried out on absorption sound property of nonwoven fabrics not great deal of research has been conducted on this aspect of knitted textile structures Despite of considerable smaller noise absorption coefficient NAC of the knitted structures in comparison to those of nonwoven fabrics the formers are used in application where the latter cannot be used due to technical or economical considerations Therefore in this work light and air permeability of warp knitted fabrics in relation to their sound absorption property has been investigated Various warp knit structures such as Tricot Locknit Reverse Locknit Sateen and Sharkskin at density low medium and high were prepared polyester filament yarn with a number yarn of 75 denier and 36 mono fillaments used light and air permeability of the samples were evaluated using the standard number of ASTM E1554 07 and ASTM D6567 00 2006 was performed using the Shirley and light meter Sound absorption property of the samples was investigated using an impedance tube Texsonic meter It was found that increase in density of the fabrics resuls in reduction of fabric porosity and light permeability In this respect no significant difference in results was observed when samples were tested on either their technical face or back As far as sound absorption property of the samples is concerned it was concluded that fabric noise absorption coefficient NAC is affected by factors such as fabric density porosity under lap course and wale direction and technical face and back It was found that fabric exhibit higher NAC when the sound waves were incident on their technical face in comparison to their technical back It can be concluded that the structure of Tricot reverse locknit and Shark Skin in comparison to the structure of sateen and locknit most of the absorption of sound light and air on the other hand it should be noted that the availability of light and air to fabrics are only dependent on the porosity Absorption of sound was evaluated at frequencies of 250 500 and 1000 Hz It was found that maximum and minimum values of sound absorption coeffiecients were occurred 250 and 1000Hz respectively For this reason it was concluded that at higher frequencies the reflection from the sample is increased It was observed that structures such as tricot shark skin and reverse locknit absorbed more sound This was attribuited to the short underlap associated with these structures It was concluded that the acoustical property of the samples was dependent upon the sound reflected from the samples Fabric with long underlap such as sateen exhibited low sound absorption and thus higher sound reflectance The results showed that generally more sound is absorbed by the technical face in comparison to technical back This phenomenon is due to existence of more yarn on the technical face of fabric in comparison the amount of yarn

كلاني، رامين

بررسي اثر ساختاري پارچه دوشاخه حلقوي تاري بر جذب صوت نفوذپذيري نور و هوا

ضريب جذب صوت , عبور نور , تخلخل , رو و پشت فني