Ashrafi, M., Poorgharibshahi, V. (2010). Analytical and Numerical Investigation of Four-roll Bending. Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering, 3(1), 47-58.
M. Ashrafi; V. Poorgharibshahi. "Analytical and Numerical Investigation of Four-roll Bending". Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering, 3, 1, 2010, 47-58.
Ashrafi, M., Poorgharibshahi, V. (2010). 'Analytical and Numerical Investigation of Four-roll Bending', Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering, 3(1), pp. 47-58.
Ashrafi, M., Poorgharibshahi, V. Analytical and Numerical Investigation of Four-roll Bending. Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering, 2010; 3(1): 47-58.
Analytical and Numerical Investigation of Four-roll Bending
1Lecturer, Mechanical Engineering Department, Islamic Azad University, Khomeinishahr Branch.
2- Lecturer, Islamic Azad University, Tiran Branch
Abstract
Four-roll bending process is usually used for manufacturing of seamed thick-walled and thin-walled cylinders. Due to complexity of this process, the analytical solution of plate bending in this process has not been developed completely. The existence of friction and multi-step processing makes it more difficult. Investigation of four-roll bending process using analytical and numerical methods is the main aim of current research. At first, using plate deformation theories, an analytical solution for four-roll bending process is extracted. By decomposing the deformation to elastic and elasto-plastic, the required bending moment is calculated. Considering the distribution of bending moment along the plate, the radius of bending is calculated considering spring back effects. The four-roll bending process is simulated by the finite element method. The simulation results show that the level of strain is less than the critical value and hence there are no damaged parts in the plate during process. Besides, bending radius of the plate after spring back is calculated and compared with the analytical values. Finally, for validation of analytical and numerical results, some experiments were conducted on aluminum. Results of this research show that both analytical and numerical methods are proper techniques for predicting plate behavior during four-roll bending.
در این تحقیق با استفاده از روشهای تحلیلی و عددی موجود، فرایند نورد چهار غلتکی در تولید استوانه‌های جدار نازک و ضخیم مورد بررسی قرار گرفته است. به همین منظور ابتدا با استفاده از روابط تحلیلی حاکم بر تغییر شکل ورق و با در نظر گرفتن دو حالت تغییر شکل الاستیک و الاستوپلاستیک ورق، گشتاور خمشی لازم برای انجام فرایند و شعاع خمش ورق پس از برگشت فنری محاسبه شده است. در ادامه با استفاده از روش اجزا محدود، نورد چهار غلتکی ورق آلومینیومی مورد بررسی قرار گرفته است. نتایج حاصل از شبیهسازیها نشان میدهند که کرنشهای به وجود آمده در ورق از حد بحرانی کمتر بوده و بنابراین ورق در حین فرایند دچار آسیب نخواهد شد. همچنین شعاع خمش ورق پس از برگشت فنری در طول ورق محاسبه و با مقدار تحلیلی آن مقایسه شد. در نهایت و به منظور صحه گذاری بر نتایج تحلیلی و عددی به‌دست آمده در این تحقیق، فرایند نورد چهار غلتکی بر روی نمونههایی از ورق آلومینیومی انجام گرفت و خروجی حاصله با نتایج تحلیلی و شبیهسازی مقایسه شد. نتایج حاصل از این تحقیق نشان میدهند که هر دو روش تحلیلی و عددی ابزاری مناسب برای پیشبینی رفتار ورق در حین فرایند نورد چهار غلتکی میباشند.
Keywords [Persian]
نورد چهار غلتکی، خمش پلاستیک ورق، برگشت فنری، شعاع خمش
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