بررسی تجربی و عددی رشد ترک خستگی در آلیاژ تیتانیوم Ti-6Al-4V در حضور تنش‌های پسماند کششی

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشگاه صنعتی امیرکبیر، دانشکده مهندسی مکانیک

چکیده

رشد ترک خستگی از مکانیزم های شکست در سازه‌های مهندسی می‌باشد که با وجود حوزه‌ی تنش پسماند کششی تشدید می‌گردد. در این پژوهش، اثر تنش پسماند کششی در جلوی جبهه ترک بر روی رشد ترک خستگی مورد بررسی قرار گرفته‌است. تنش پسماند مکانیکی با استفاده از روش خمش چهار نقطه بر روی نمونه ها اعمال شده است و همچنین اندازه‌گیری تنش پسماند با استفاده از روش کرنش سنجی سوراخ انجام گرفته است. آزمون رشد ترک خستگی بر روی نمونه‌های خمشی با ترک لبه دارای تنش پسماند و بدون تنش پسماند صورت پذیرفته و تکرارپذیری آزمایش بررسی شده است. به منظور بررسی ناحیه پلاستیک نوک ترک، تنش پسماند اعمالی و بدست آوردن پارامتر‌های مکانیک شکست از نرم‌افزار تجاری آباکوس استفاده شده است. نتایج بررسی‌ها میزان افزایش نرخ رشد ترک خستگی در حضور تنش پسماند کششی را نشان می‌دهد. این افزایش نرخ رشد ترک خستگی تا 50 درصد می‌تواند عمر خستگی را کاهش دهد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

A Numerical and Experimental Study on Fatigue Crack Growth of Ti-6Al-4V Specimens in Presence of Tensile Residual Stresses

نویسندگان [English]

  • AmirMohammad Zangeneh
  • Iraj Sattarifar
  • Mohammad Noghabi
Department of Mechanical Engineering, Amirkabir University of Technology
چکیده [English]

Fatigue crack growth is one of the failure mechanisms in engineering structures, which is intensified by the presence of tensile residual stress. In this research, the effect of tensile residual stress in front of the crack front on fatigue crack growth has been investigated. The mechanical residual stress has been applied to the samples using the four-point bending method, and the residual stress has also been measured using the hole drilling method. Fatigue crack growth tests were performed on single edge notch bend samples with residual stress and without residual stress and the repeatability of the test was checked. To investigate the plastic area ahead of the crack tip, the applied residual stress, and obtain the fracture mechanics parameters, Abaqus commercial software has been used. The results of this study show the increase in the rate of fatigue crack growth in the presence of tensile residual stress. This increase in fatigue crack growth rate can reduce fatigue life up to 50%.

کلیدواژه‌ها [English]

  • Fatigue crack growth
  • residual stress
  • titanium alloy
  • J-integral
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