پديد آورنده :
اسكندري، حجت اله
عنوان :
بررسي عملي و نظري شكست در روكش هاي لاستيكي پينچ رول
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
طراحي كاربردي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
نه،83ص:مصور،جدول، نمودار
يادداشت :
ص.ع. به: فارسي و انگليسي
استاد راهنما :
محمد رضا فروزان
استاد مشاور :
سعيد نوري خراساني
توصيفگر ها :
مكانيك شكست , انتگرال J , رشد ترك خستگي
تاريخ نمايه سازي :
27/10/88
استاد داور :
محمود سليمي، سعيد ضيايي راد
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتال
چكيده انگليسي :
An Experimental Analytical Investigation into the Fracture of Rubber Cover of the Pinch Roll Hojjat Eskandari H Eskandari@me iut ac ir February 18 2009 Department of mechanical Engineering Isfahan University of Technology Isfahan 84156 83111Degree M Sc Language FarsiM R Forouzan Assist Prof Supervisor Forouzan@cc iut ac irAbstract Rubber covered pinch rolls are used in the cold rolling shops for feeding the steel coils into the product line These rolls only provide required force for pinching the steel strip and have no effect on thickness and surfaceprecision After a short working period almost 3 to 6 months the rubber cover of the pinch rolls fails due torupture The main aim of this research was to find the best type of compound among polyurethane compounds Inorder to test the compounds a semi full scale test machine was developed Then several tests were set up to measureeffect of each load It should be mentioned that there were two main mechanical loads on PU layer of the pinch roll A normal load that provided by two hydraulic actuators and affect on both end of the rolls and a tensile load thatimposed by pay off reel on steel strip that was connected with rubber cover First normal load was imposed to evaluate the effect of this force solitarily to find maximum load and rotationalvelocity that can be applied to the system Because in cyclic loading hysteresys phenomena occurs and result inmaterial warming normal load and rotational velocity are limited In next test in order to must simulate the pay offreel tensile load a reverse moment on upper roll is applied by a gear pump Unfortunately this method failedbecause of hydraulic system and low power of electrical motors A successful test was set up and tested by adding third roll that apply tension to the rubber belt which wasmanufactured by a closed seamless die Numerical analysis of each test was performed by the powerful finite element software ABAQUS Eventuallythese results were obtained 1 The higher the rubber hardness the more the fracture strength against crack growth For example rubber with 90 Shore A hardness ruptured later than one with 85 Shore A 2 Using data obtained from experimental results the cycles that each rubber belt with determined hardness under loading condition endures until ruptures and also parameters calculated from software analyzing process J integral values mechanical crack growth constants were calculated for each rubber 3 Theoretically mechanical crack growth initiates when J 40 j m2 that is confirmed with test and real pinch roll 4 With consideration to numerical results Mode I loading i e Opening Mode is distinguished to have the most effect on fatigue crack growth 5 Locations of occurrence the maximum J integral values have been determined for tests and real case Key Words Fracture Mechanics Rubber Pinch Roll J Integral Crack Growth
استاد راهنما :
محمد رضا فروزان
استاد مشاور :
سعيد نوري خراساني
استاد داور :
محمود سليمي، سعيد ضيايي راد
