نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار،دانشکده مهندسی مکانیک، دانشگاه علم و صنعت ایران ، تهران، ایران

2 کارشناسی ارشد،دانشکده مهندسی مکانیک، دانشگاه علم و صنعت ایران، تهران ، ایران

چکیده

نسبت مقاومت و سفتی به وزن بالا، از مهم‌ترین مزیت‌های کامپوزیت‌ها بوده که باعث کاربرد گسترده این مواد در صنایع مختلف شده است. کامپوزیت‌ها به‌دلیل وجود مکانیزم‌های آسیب مختلف و نرخ متفاوت رشد و تأثیر این مکانیزم‌ها بر یکدیگر نسبت به فلزات دارای پیچیدگی بیشتری می‌باشد. در این مقاله، به‌‌منظور پیش‌بینی عمر خستگی و شبیه‌سازی افت سفتی در چندلایه‌های کامپوزیتی تحت بارگذاری خستگی مدلی مبتنی بر مکانیک خرابی محیط‌های پیوسته توسعه داده شده است. متغیرهای آسیب برای شبیه‌سازی افت خواص الاستیک در رزین، الیاف و جهت برشی در نظر گرفته می‌شوند. ثابت‌های مادی در قوانین رشد آسیب رزین، الیاف و جهت برشی، از آزمایشات روی چند‌لایه‌های تک‌جهته ،  و چندلایه متعامد  قابل استخراج می‌باشد. به‌منظور ارزیابی مدل در بارگذاری چندجهته، نسبت‌های تنش متفاوت و وضعیت‌های تنش دلخواه از نتایج تجربی در دسترس بر روی چند‌لایه‌های تک‌جهته کامپوزیتی ،  و  تحت بارگذاری کششی استفاده شده است. همچنین به‌منظور ارزیابی مدل برای چندلایه‌های کامپوزیتی دارای تمرکز تنش از نتایج آزمایشی بر روی چندلایه متعامد  و تحت بارگذاری پین استفاده شده است. نتایج حاصل بیانگر توانایی مدل در پیش‌بینی عمر خستگی چند‌لایه‌های تک‌جهته و متعامد کامپوزیتی تحت بارگذاری تک‌جهته و چند‌جهته و در وضعیت‌های مختلف تنش می‌باشد.

کلیدواژه‌ها

عنوان مقاله [English]

Fatigue life prediction of laminated composites under multiaxial fatigue loading condition by using developed continuum damage mechanics model

نویسندگان [English]

  • Bijan Mohammadi 1
  • Babak Fazlali 2

1 Departmen of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran

2 Departmen of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran

چکیده [English]

One of the main advantages for the increasing engineering application of composites in weight-critical structural applications is their high specific stiffness and strength. Composite materials behavior is complicated more than metallic material because of different mechanisms, damage growth rate and effect of them in each other. In this paper, a continuum damage mechanics based model is developed to simulate stiffness degradation and fatigue life prediction of laminated composites under fatigue loading conditions. Damage parameters are used to estimate the degradation of elastic properties in matrix, fiber and shear direction. The material properties of the damage evolution equations are derived by testing on 0° and 90° unidirectional plies and  cross-ply laminate. To evaluate the model under multiaxial fatigue loading, arbitrary states of stress and stress ratio available results of experiments on unidirectional 90 , 0  and 30  plies under fatigue loading conditions are used. Also, to evaluate the model for composite laminates with stress concentration results of experiments of pin-loaded cross-ply  laminate are used. The obtained results show the capability of proposed model in fatigue life prediction of unidirectional and cross-ply laminates under uniaxial and multiaxial fatigue loading with different states of stress.

کلیدواژه‌ها [English]

  • Continuum damage mechanics
  • Life prediction
  • Stiffness degradation
  • Laminated composites

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