6962

6504

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1390

ده، 112ص.: مصور، جدول،نمودار

ص.ع. به فارسي و انگليسي

مهران مرادي

محمد مشايخي

4/6/91

محمدرضا فروزان، صالح اكبرزاده

1396/09/18

كتابنامه

مكانيك

مهندسي مكانيك

ID6504

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Finite Element Analysis of Deep Drawing with Anti Lock Braking System and Investigation of ABS Frequency Mohamad Hedayati Email address m hedayati@me iut ac ir Date of Submission 26th February 2012 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor s Name Mehran Moradi Assistant Professor moradi@cc iut ac irAbstractDeep drawing is one of the most important operations in sheet metal forming There are numerous factors affecting the drawing process such as the shape of the die the properties of the material the shape and size ofthe blank the boundary conditions the friction and lubrication conditions between the die and the blank Limiting drawing ratio LDR which is the ratio of the initial diameter of a blank that can be drawn withoutfailure to the punch diameter is commonly used to provide a measure of the drawability of sheet metal Due tolimitation in LDR highly deep cups cannot be obtained with a single drawing operation Disadvantages ofredrawing have caused many studies to increase LDR The method of using anti lock braking system in deepdrawing has recently attracted attention of many researchers This approach is the same as conventional deepdrawing with the exception that the blank holder switches between gripping and releasing the blank in shortintervals during forming process It looks much like the ABS systems used in braking system of autos Modeling of the drawing instrument was done via Finite Element Analysis software ABAQUS EXPLICIT Blank is made of AA5754 O aluminum Punch die and blank holder were modeled as rigid bodies The blank ismodeled using a 4 node doubly curved thin shell element with reduced integration S4R Results show that oscillatory blank holder causes an obvious increase in draw depth and significantly decreasesear heights Results of the analysis emphasize the fact that blank holder gap and its oscillation amplitude andfrequency can significantly influence the benefits of deep drawing with ABS Improvement in cup depth wasobserved as the frequency increased up to a certain limit after which no further improvement was noticed Onthe other hand pulsation amplitude of the BHG seemed to play a decisive role in the performance of pulsatingBHG schemes Increasing the pulsation amplitude was found to decrease the friction force between the blankand the blank holder and increase the drawing depth Aslo increasing amplitude and frequency up to a certainlimit decreases the ear heights There is meaningful relation between dercrease the ear heights and decreases thefriction force It was observed that pulsation the blankholder induced sinusoidal variations in the punch force signal and alsonoted that these variations were directly proportional to the BHG amplitude In the case of low frequencies the phase of oscillation is also important This observation has enabled a strategyto be developed which enables sound parts to be drawn This is achieved by pulsation the blankholder at anultra low frequency and ensuring that the pulsating blank holder gap is asynchronous with the punch force andremains within the process BHG limits for the entire width of the critical tearing window Keywords Deep drawing Oscillatory blank holder Anti lock braking system Ultra low frequency

مهران مرادي

محمد مشايخي

محمدرضا فروزان، صالح اكبرزاده