تحلیل ترک در محل اتصال پوسته-نازل یک مخزن استوانه‌ای تحت فشار داخلی با استفاده از روش انتگرال-جی

نوع مقاله : مقاله پژوهشی

نویسنده

استادیار، گروه مهندسی مکانیک، دانشگاه صنعتی اراک، اراک، ایران

10.22034/ijme.2023.425735.1875

چکیده

این مقاله به ارزیابی عددی یک عیب ترک در محل گوشه اتصال پوسته-نازل یک مخزن تحت فشار داخلی، مورد استفاده در صنعت نفت و گاز، با روش انتگرال- جی میپردازد. در ابتدا با استفاده از روش انتگرال دامنه سه بعدی و برای حالت الاستیک خطی، روابط مربوط به محاسبه انتگرال- جی بدست آمده است. مزیت متمایز استفاده از این انتگرال در مکانیک شکست، قابلیت آن در تخمین دقیق ضریب شدت تنش ترک در نقاطی دور از نوک آن، که در آنجا گرادیان تنش و کرنش بالاست، می‌باشد. روش مدل سازی در نرم افزار آباکوس به تفصیل تشریح شده است و قابل تعمیم به سایر نقاط هندسی در انواع مخازن و نیز اشکال دیگر عیوب ترک می‌باشد. به منظور راستی آزمایی مدل عددی، نتایج بدست آمده از آن با نتایج حل تحلیلی مقایسه شده است و انطباق خوبی بین دو دسته از جواب ها مشاهده می‌شود. بیشترین اختلاف مربوط به مقایسه نتایج مدل عددی با نتایج حاصل از WRCB-175 به میزان 30 درصد می‌باشد که ناشی از ملحوظ داشتن ضرایب تصحیح و ایمنی در WRCB-175 می باشد. همچنین استقلال از مسیر انتگرال-جی برای همگی کانتورهای اطراف ترک با مقدار خطای کمتر از 0.15% مشاهده گردید. به طور کلی، نتایج این تحقیق به بازرسین فنی و مهندسین ایمنی در صنعت نفت، گاز و پتروشیمی کمک خواهد کرد تا ارزیابی دقیق تری از وضعیت ایمنی و سلامت تجهیزات داشته باشند.

کلیدواژه‌ها


عنوان مقاله [English]

Analysis of a Crotch corner crack in the shell-nozzle junction of a cylindrical pressure vessel under internal pressure using the J-integral method

نویسنده [English]

  • Hamid Ghasemi Mighani
Assistant Professor, Mechanical Engineering Department, Arak University of Technology, Arak, Iran
چکیده [English]

This paper implements the J-integral method to numerically analyze a crotch corner crack in the shell-nozzle junction of an internally pressurized cylindrical pressure vessel, which is used in oil and gas industry. Firstly, by using the three-dimensional domain integral method and for linear elasticity, the equations to calculate the J-integral have been derived. The distinct advantage of using this integral in fracture mechanics is its ability to accurately estimate the stress intensity factor of the crack at points far from its tip, where the stress and strain gradients are high. Secondly, the implementation of the methodology in Abaqus software is described in detail. The methodology can be extended to other locations of vessels and various types of cracks. In order to verify the model, numerical results have been compared with the analytical ones, and a good conformity between them was observed. In fact, the largest difference of 30% is due to correction and safety factors which are considered in WRCB-175. The path independence of the J-integral was also observed for all contours with the error less than 0.15%. In general, the outputs of this research will help inspectors and safety engineers involved in the oil, gas and petrochemical industry to make a more accurate assessment of the safety and health status of equipment.

کلیدواژه‌ها [English]

  • J-integral
  • Crack
  • Stress Intensity Factor (SIF)
  • Abaqus
  • Finite Element Method (FEM)
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