مقایسه ترمیم به کمک وصله کامپوزیتی و نیروی پیش‌بار پیچ بر روی ورق آلومینیوم ترک‌دار

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده فنی و مهندسی مکانیک، دانشگاه تبریز، تبریز، ایران

چکیده

بسیاری از قطعات موجود در صنایع مختلف حین کار تحت تأثیر تنش های چند محوری قرار دارند. از آنجایی که مبدأ شروع شکست این قطعات، ترک ها می باشند بنابراین تحلیل استحکام سازه های ترک دار تحت بارهای چند محوری و تلاش برای افزایش استحکام و پایداری آن ها بسیار بااهمیت است. در این مقاله تأثیر نیروی پیش بار ناشی از اتصالات پیچ و مهره و وصله کامپوزیتی بر اشاعه ترک جانبی موجود در یک نمونه مستطیلی از جنس آلیاژ آلومینیوم  2024-T3 به صورت تجربی و تئوری موردمقایسه قرارگرفته است. برای ایجاد مود کششی خالص، برشی خالص و مود ترکیبی نمونه ترک دار، دستگاه اصلاح شده آرکان مورداستفاده قرارگرفته و در حل تئوری نیز از نرم افزار المان محدود انسیس استفاده شده است. نتایج این تحقیق نشان دهنده افزایش چشمگیر استحکام کششی قطعات ترمیم شده با این دو روش، در مقایسه با قطعات ترک دار ساده می باشد. در بهترین حالت افزایش استحکام کششی قطعات ترمیم شده توسط وصله کامپوزیتی برای مود کششی خالص 44 درصد بوده که این میزان با کاهش سهم مود یک در بارگذاری کاهش می یابد تا در مود برشی خالص به 9 درصد می رسد. نیروی پیش بار نیز در بهترین حالت، استحکام نمونه های ترمیم شده را 24 درصد برای مود برشی خالص افزایش می دهد که با افزایش سهم مود یک در بارگذاری این میزان به 18 درصد کاهش می یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Comparison Between Composite Patches and Bolt Clamping Force to Repair an Edge Crack in Aluminum Alloy 2024-T3 Specimens

نویسندگان [English]

  • H.N. Maleki
  • T.N. Chakherlou
Department of Mechanical Engineering, University of Tabriz, Tabriz, Iran
چکیده [English]

Many of components in various industries are working under multiaxial stresses, and since the cracks can be the source of the failure, therefore, the strength analysis of the cracked structures under mixed- mode loads and trying to increase the strength and stability of them is very important. In this paper, the effect of the composite patch and clamping force resulted from torque tightening a nut and bolt on the fracture strength of an aluminum alloy 2024-T3 plate having an edge crack has been compared experimentally and numerically. The cracked test specimens were loaded using modified Arcan fixture to create pure opening fracture mode (mode I), pure in-plane shear fracture mode (mode II) and mixed mode of (I and II). In the numerical part, Ansys finite element package was used to simulate the test specimens performance. The results of this study showed a significant increase in tensile strength of the repaired components by using these two methods compared to simply cracked specimens. Thus, an increase of 44% in the tensile strength of mode I can be achieved with a composite patch, however, the strength increase is reduced to 18% in pure shear mode. Clamping force also increases the fracture strength in mixed mode. This increase is 24% for pure shear mode and it reaches 9% in the pure tensile mode.

کلیدواژه‌ها [English]

  • Fracture mechanics
  • Mixed mode
  • Bolt clamping force
  • Composite patch
  • Stress intensity factor
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