نوع مقاله : مقاله پژوهشی

نویسندگان

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

2 دانشجوی دکترا، مهندسی هوافضا، دانشکده مهندسی مکانیک، دانشگاه علم و صنعت، تهران، ایران

چکیده

با توجه به گسترش استفاده از مواد مرکب در صنایع مختلف، همواره افزایش دقت در تحلیل خستگی سازه‌های مرکب موردتوجه است. با توجه به ساختار سازه‌های ساندویچی، حالت‌های خرابی مختلفی هنگام بارگذاری متناوب در این سازه‌ها به وجود می‌آید. هرچه تأثیر این حالت-ها بر یکدیگر هنگام ارزیابی عمر خستگی دقیق‌تر در نظر گرفته شود، دقت پیش‌بینی‌ها افزایش می‌یابد. در این پژوهش به کمک ترکیب دو زیر برنامه‌ی USDFLD و UMAT در نرم-افزار آباکوس ابزار جدیدی ارائه‌شده است تا اثر متقابل خستگی پوسته-های سازه‌ی ساندویچی و همچنین جدایش بین پوسته و هسته بر یکدیگر با استفاده از مدل‌های موجود دیده شود. این ابزار پس از اعتبار سنجی برای ارزیابی خستگی یک صفحه‌ی ساندویچی با هسته‌ی PVC با سفتی‌های متفاوت 50MPa، 3GPa و 1GPa و پوسته‌ی AS4/3501-6 با لایه چینی [0]4، [90]4 ‌استفاده‌شده است. در این تحلیل جدایش بین پوسته و هسته به کمک مدل ناحیه‌ی چسبنده و خستگی پوسته توسط مدلی بر پایه‌ی انرژی به‌صورت هم‌زمان استفاده‌شده است و اثرات حالت‌های خرابی بر یکدیگر در نظر گرفته‌شده است. نتایج نشان دادند که با افزایش سفتی هسته شروع جدایش ناحیه‌ی اتصال هسته و پوسته دیرتر رخ می‌دهد و جدایش بین پوسته و هسته به سمت لبه‌های آزاد صفحه می‌رود. همچنین مشاهده شد که خرابی کنترل‌کننده‌ی عمر این سازه حالت جدایش بین پوسته و هسته است. نتایج بیانگر کاهش نرخ رشد پارامتر خرابی در ناحیه‌ی چسبنده در یک نقطه‌ی مشخص، افزایش نرخ رشد سطح ترک بین پوسته و هسته و افزایش نرخ رشد پارامتر خرابی در پوسته‌ در طول بارگذاری ‌هستند.

کلیدواژه‌ها

عنوان مقاله [English]

Fatigue analysis of composite sandwich panel by continuum damage mechanics method with interlayer element

نویسندگان [English]

  • Bijan Mohammadi 1
  • Mohammad Hojat Vatankhah 2

1 Associate Professor, Faculty of Mechanical Engineering, Iran University of Science and Technology, Tehran

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

چکیده [English]

According to the structure of sandwich panels, different failure modes occur during periodic loading in these structures. When the effect of these modes on each other is considered the predictions will be more accurate. In this research, a new tool presented with the help of the combination of USDFLD and UMAT subroutine in the Abaqus software to see the mutual fatigue effect of the face and the delamination between the face and the core using the existing models. This tool is used to fatigue analysis of a sandwich beam with a PVC core with different stiffness and AS4/3501-6 composite faces with [0]4, [90]4 layup. The delamination between the face and the core is analyzed by cohesive zone model and the face fatigue by an energy-based model simultaneously. The results showed that with the increase of the core stiffness, the delamination between the face and the core, caused by fatigue, begins later and moves towards the free edges of the plate. It was also observed that the failure mode that controls the life of this structure is the delamination between the face and the core. The results show the decrease in the growth rate of the damage parameter in the cohesive zone for specified element, increase of the crack growth rate and growth rate of the damage parameter in the face during loading.

کلیدواژه‌ها [English]

  • Cohesive zone
  • Continuum damage mechanic
  • Finite element
  • Sandwich panel
  • Fatigue analysis
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