بررسي تجربي و عددي پارامترهاي موثر بر گشتاور و توان در فرايند شكل‌دهي غلتكي سرد مقاطع كانال متقارن

Numerical & experimental study of effective parameters on the load and forming torque of rolls in the cold roll forming of symmetric channel section

در اين مقاله عوامل موثر بر گشتاور شكل‌دهي ــ شامل هندسه‌ي غلتك، ضخامت ورق، تنش تسليم ورق، عرض ورق و زاويه‌ي شكل‌دهي ــ و نيز توان مورد نياز در فرايند شكل‌دهي غلتكي سرد بررسي مي‌شود. با توجه به ثابت‌بودن عرض كف پروفيل، افزايش عرض ورق سبب افزايش عرض بال مقطع مي‌شود. اين فرايند با نرم‌افزار اجزا محدود Abaqus براي دو نوع هندسه با غلتك‌ بالايي تخت و زاويه‌دار شبيه‌سازي شد. نتايج شبيه‌سازي‌ها نشان داد كه افزايش استحكام تسليم، زاويه‌ي شكل‌دهي و ضخامت ورق، به افزايش گشتاور وارد شده به غلتك‌ها مي‌انجامد و درنتيجه توان شكل‌دهي افزايش مي‌يابد. افزايش عرض ورق باعث كاهش گشتاور مورد نياز براي شكل‌دهي مي‌شود. نتايج نشان مي‌دهد كه مقدار گشتاور اعمالي به غلتك‌ها و درنتيجه توان مورد نياز شكل‌دهي براي ايستگاه شكل‌دهي با غلتك‌هاي بالايي تخت در تمام حالت‌هاي مورد بررسي كم‌تر است. بررسي تاثير ضخامت و عرض ورق در آزمايش‌هاي تجربي، مويد شبيه‌سازي‌هاي اجزاي محدود است.

Cold roll forming is one of the most complex forming processes in which quality of products is highly dependent on the process parameters. Estimation of forming torque and power in the cold roll forming process is one of the most important parameters. Effective parameters on the forming torque and forming power are investigated in the present study. These parameters are rolls geometry, sheet thickness, sheet width, strength of sheet, and forming angle. So, the forming process is simulated in the finite element software Abaqus for both flat and angled geometry of the top roll. Simulation results show that with yield strength, sheet thickness, and increase of roll angle, forming torque and power will increase. Also, the rolls force increase and the forming torque decrease with sheet width increasing. The results of this study show that the forming torque and power for the top roll with flat geometry is lesser than the top roll with angled top roll. Due to easier process of manufacturing of flat rolls, this type of rolls geometry can be used for channel sections. The effect of thickness and width of sheet is investigated experimentally on the forming torque and power. Numerical results are verified by experimental results of the present study. Results show that forming torque and power increase with yield strength, then forming angle and sheet thickness increase as well. Therefore, engineers can consider the effects of these parameters on the forming torque, forming power, and selecting proper type of motors. Edge longitudinal strain of numerical simulations of the present study is verified by numerical results of Lindgeren, 2007 [8]. This comparison shows that numerical results of the present study is near to the results of Lindgeren, 2007. Results show that edge longitudinal strain decreases with the increase of yield strength. These results also show that the increase of edge longitudinal with the increase of roll forming angle.