نوع مقاله: مقاله پژوهشی

نویسنده

دانشیار، دانشکده مهندسی مکانیک، پژوهشگاه هوافضا، وزارت علوم، تحقیقات و فناوری، تهران، ایران

چکیده

مدل میکرومکانیکی برای تحلیل شکست مواد مرکب تقویت‌شده با الیاف تک‌جهته در بارگذاری عرضی ارائه می‌شود که علاوه بر مدل‌سازی رفتار غیرخطی زمینه در اثر بارگذاری بیش از حد تسلیم آن، قابلیت مدل‌سازی عیوب ناشی از جدایش بین زمینه و الیاف و ترک‌های زمینه را دارد. میکروساختار مواد مرکب با استفاده از سلول‌های واحد و با فرض متناوب بودن میکروساختار توصیف می‌شود که در آن الیاف به‌صورت منظم یا غیرمنظم توزیع شده است. مدل میکرومکانیک برای تعیین استحکام عرضی مواد مرکب با زمینه‌ی آلومینیوم و الیاف کربن استفاده می‌شود که الیاف با توجه به صلبیت بالای آن‌ها با مدل الاستیک خطی همسانگرد و زمینه با مدل الاستیک-پلاستیک همسانگرد توصیف می‌شود. معیار پیدایش عیوب در زمینه براساس معیار حداکثر کرنش اصلی و با توجه به میزان کرنش نهایی ماده‌ی زمینه توصیف می‌شود که افزایش تنش اعمالی پس از پیدایش عیب منجر به کاهش سفتی ماده و در نهایت ایجاد ترک در ماده‌ی زمینه می‌شود. اتصال بین زمینه با استفاده از مدل چسبناکی توصیف و پیدایش عیوب در آن با توجه به میزان استحکام محوری و برشی اتصال تعیین می‌شود. مدل میکرومکانیک برای مطالعه‌ی اثر توزیع هندسی الیاف در میکروساختار، درصد حجمی الیاف، اثر استحکام اتصال بین زمینه و الیاف استفاده شده و نواحی ایجاد عیوب و نحوه‌ی گسترش آن‌ها، علاوه بر نمودارهای تنش-کرنش در ماده مرکب تعیین می‌شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Micromechanical fracture modeling of unidirectional composite material under transverse loading

نویسنده [English]

  • Mohammad Tahaye Abadi

Aerospace Research Institute, Ministry of Science, Research and Technology, Tehran, Iran

چکیده [English]

A micromechanical model is presented to analyze the fracture response of unidirectional composite materials considering the nonlinear behavior of matrix material under loading more than the yield strength as well as the fiber-matrix debonding and matrix cracking. The composite microstructure is characterized with repeating unit cell with regular or random fiber-packing patterns. The micromechanical model is employed for composite material with aluminum matrix and carbon fibers. The high rigidity fibers are modeled as linear isotropic elastic material, while matrix material is characterized with elastic-plastic model. The damage initiation stage in matrix material is described by principal strain criterion accompanied with damage evolution considering stiffness degradation up to crack formation. The bonding between fiber and matrix is modeled using cohesive model, in which damage initiation criterion depends on the normal and shear strength of the cohesive zone. The micromechanical model is employed to study the effects of fiber distribution, fiber volume fraction, fiber-matrix bonding strength on the crack propagation through the microstructure as well as the stress-stain graph up to the fracture of microstructures.

کلیدواژه‌ها [English]

  • Fiber-matrix debonding
  • Matrix Cracking
  • Micromechanics
  • Fracture strength

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