نشریه مهندسی مکانیک امیرکبیر

نشریه مهندسی مکانیک امیرکبیر

کالیبراسیون و اعتبارسنجی مدل شکست نرم برای فولاد اس‌تی-37 تحت حالت‌های مختلف تنش

نوع مقاله : مقاله پژوهشی

نویسندگان
دانشکده مهندسی مکانیک، دانشگاه تهران، تهران، ایران
چکیده
اثرات تنش سه‌محوره و پارامتر زاویه لود بر رفتار شکست نرم در فولاد اس‌تی-37 در این پژوهش مورد بررسی قرار گرفته است. برای مطالعه شرایط تنش سه‌محوره منفی، آزمایش‌های کشش و فشار تک‌محوره بر روی نمونه‌هایی با هندسه‌های ویژه، شامل نمونه‌های دمبلی و نمونه‌های مستطیلی دارای سوراخ‌های منحنی بیضوی، انجام شده است. مقادیر تنش سه‌محوره منفی در بازه0/348 - تا 0/456- ایجاد شدند. یک رویکرد ترکیبی تجربی-عددی برای تحلیل رفتار شکست به کار گرفته شد. در بخش عددی، مدل شکست گنجیانی با در نظر گرفتن پارامترهای آسیب در قالب شبیه‌سازی اجزای محدود در نرم‌افزار آباکوس و با استفاده از زیرروال‌های وی‌یوهارد و وی‌یواس‌دی‌اف‌ال‌دی پیاده‌سازی شد. تحلیل مقایسه‌ای نتایج تجربی و عددی نشان‌دهنده تطابق مناسب در پیش‌بینی کرنش شکست است. ارزیابی عددی نشان داد که شکست در ناحیه‌ای رخ می‌دهد که بیشترین کرنش پلاستیک در آن متمرکز می‌شود. نتایج تأیید می‌کنند که تنش سه‌محوره تأثیر قابل‌توجهی بر شکست نرم دارد و همچنین مشاهده شد که تغییرات کرنش شکست تحت تنش سه‌محوره مثبت و منفی روندهای یکسانی را نشان می‌دهد.
کلیدواژه‌ها
موضوعات

عنوان مقاله English

Calibration and Validation of a Ductile Failure Model for ST-37 Steel under Various Stress States

نویسندگان English

Mohsen Mansouri
Seyed Mehdi Ganjiani
Department of Mechanical Engineering, University of Tehran, Tehran, Iran
چکیده English

In this research, the effects of stress triaxiality and the Lode angle parameter on the ductile fracture behavior of ST-37 steel have been studied in detail. To investigate negative stress triaxiality conditions, uniaxial tensile and compression tests were performed on specimens with specific geometries, including dog-bone shaped specimens and notched specimens with elliptical holes. These experiments enabled the creation of negative stress triaxiality values within the range of -0.348 to -0.456. A combined approach, encompassing both experimental and numerical methods, was employed for the accurate analysis of fracture behavior. In the numerical part, the Ganjiani fracture model, considering damage parameters, was implemented through finite element simulations in Abaqus software, utilizing the VUHARD and VUSDFLD user subroutines. The comparative analysis of experimental and numerical results demonstrated a significant agreement in predicting the fracture strain. Numerical evaluations further revealed that fracture concentrates in regions with the highest plastic strain. These findings support the notion that stress triaxiality plays a crucial role in ductile fracture. Furthermore, it was observed that the trends in fracture strain variations under both positive and negative stress triaxiality are similar and consistent. This research provides deep insights into the fracture mechanisms of ST-37 steel under complex stress conditions.

کلیدواژه‌ها English

Fracture Strain
Negative Stress Triaxiality
Lode Angle Parameter
Ductile Fracture Behavior
ST-37 steel
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