9795

9039

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان،دانشكده مكانيك

1393

[هفده]، 79ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

پيمان مصدق، صالح اكبرزاده

مسعود عطاپور

94/1/29

احسان فروزمهر، محسن بدرسمايي

1396/09/25

كتابنامه

مكانيك

مهندسي مكانيك

ID9039

چكيده بررسي رفتار اصطكاكي و سايشـي شيشـه اپتيكـي 7 BK در ـ ـ ـ تماس با ساچمه آلومينا در دماها بالا موضوع اين پروژه ميباشد از جمله كاربردها شيشه اپتيكي 7 BK در توليد لنزها اپتيكي طـي ـ فرايند قالبگير در دما نزديك دما گذار دما انتقال شيشـها ـ ميباشد به منظور بررسي رفتار اصطكاكي و سايشي شيشه اپتيكـي 7 BK ـ از دستگاه پين رو ديسك دما بالا استفاده شده و تاثير پارامترها سرعت لغزشي بارعمود و دما مورد بررسي قرار گرفته شده است به منظور انتخاب سطوح بار عمودي و سرعت لغزشي از نتايج آزمايشهاي بارپذيري بهره گرفته شده و دماهـا بـالاتر و پـايينتـر از دمـا ـ ـ ـ ـ ـ انتقال شيشها انتخاب شده است آزمايشها تكرارپـذير و همچنـين ـ ـ آزمايش صحتسنجي برا اطمينان از نتايج آزمايشگاهي انجام شده است كه نتايج قابل قبولي حاصل گرديده اسـت بـرا شـبيهسـاز رفتـار ـ ـ ـ ـ ـ اصطكاكي ايستايي لغزشي از سيسـتم فنـر و دمپـر مـوازي اسـتفاده ـ ـ ـ ـ ـ كردهايم و نتايج بدست آمده بهمنظور اعتبارسنجي نتايج آزمايشگاهي استفاده شده است در ادامه اين پروژه بررسي رفتار سايشي شيشـه ـ اپتيكي 7 BK در دماهاي مختلف به كمك معادلـهي آرچـارد و تعيـين ـ ـ ـ ضريب سايش ضريب K پرداخته شده است مشـاهده گرديـد كـه نيـروي ـ ـ ـ ـ اصطكاك و نرخ سايش شيشه اپتيكي 7 BK تابعي از سرعت لغزشـي دمـاي ـ ـ شيشه و فشارعمودي سطح ميباشد و با افزايش نيـرو عمـود و كـاهش ـ ـ ـ سرعت لغزشي نيروي اصطكاك و نرخ سايش شيشه اپتيكي 7 BK افـزايش ـ يافته است و با افزايش دما ديسك از 035 درجه سانتيگراد تـا 006 ـ درجه سانتيگراد بهدليل رفتار ويسكوالاستيك شيشه نيروي اصـطكاك و ـ نرخ سايش شيشه اپتيكي 7 BK افزايش يافته است و با افزايش دمـا از ـ 006 درجه سانتيگراد تا 036 درجه سانتيگراد بهدليل رفتار ويسـكوز ـ شيشه هم در مقدار نيروي اصطكاك و هم در نرخ سـايش شيشـه اپتيكـي ـ ـ ـ 7 BK كاهش مشاهده شده است واژههاي كليدي دماي انتقال شيشهاي ويسكوالاستيك آزمايش لغزشي ايستايي اصطكاك ديسك روي پين اصطكاكي

81 h reiszadeh@me iut ac ir Date of Submission 2015 01 6 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Peiman Mosaddegh mosadegh@cc iut ac ir Saleh Akbarzadeh s akbarzadeh@cc iut ac irAbstract In recent years small to medium size optical lenses are produced by precision glass modelingtechnology which is a cost effective method in comparison to conventional grinding lapping and polishingprocesses An application of BK7 optical glass is in production of optical lenses These lenses have beenproduced using glass molding in its transitional temperature Due to the difference in the thermal expansionof glass and mold material the produced lens does not have the geometry of mold Currently manufacturersuse trial and error method for making molds which is a time consuming and expensive method Simulationcan be a solution to tackle this problem but a realistic simulation needs knowing the frictional and materialbehavior of glass at elevated temperatures Today the challenge in glass molding is designing the geometryof model to achieve the right form of lens within the micron accuracy So the simulation can save the timeand cost of modeling The lack of knowledge in frictional and material behavior of glass in transitiontemperature range brings difficulty to the realistic simulation in glass modeling technology process Atelevated temperatures glass shows different frictional behavior in contact with a metal surface moldsurface since it becomes a viscoelastic material at these temperatures One of the characteristics of friction isstick slip frictional phenomena The spring damper system was used to describe the stick slip frictionalbehavior at elevated temperatures To find spring and damper coefficients a subroutine which was composedusing MATLAB was employed In order to design the experiments three factors including rotational speed temperature and vertical load each in three levels were considered To determine the behavior in glasstransition temperature range temperatures above and below the glass transition temperature were used Hightemperature pin on disk device was used for performing the experiments at high temperatures under dryfriction The pin in the experiments is made of alumina The experimental results show that with increasingtemperature up to the transitional temperature frictional force increases Further increase in the temperatureresults in a decrease in the friction force To check the wear behavior at different temperatures using Archardequation intended to determine the coefficient of wear Based on the data obtained from the experimentalresults it was observed that with increasing temperature to glass transition temperature wear coefficientincreased and with increasing temperature to 630 C to melt the glass the wear coefficient is reduced Bothexperimental and theoretical results are reasonably compatible with each other since the model is selectedcorrectly It is observed that in BK7 optical glass the friction force and wear volume are a function of slidingspeed temperature and pressure Key Words Glass Transition Temperature Wear BK7 Optical Glass Friction Viscoelastic Pin onDisc Stick Slip Behavior

پيمان مصدق، صالح اكبرزاده

مسعود عطاپور

احسان فروزمهر، محسن بدرسمايي