نصب یک مدل رفتاری الاستوپلاستیک – ویسکوپلاستیک خاک در کد ABAQUS و اعتبارسنجی آن بر اساس نتایج آزمایشگاهی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه بوعلی سینا/همدان/ایران

2 دانشگاه بوعلی سینا

چکیده

تاکنون تلاش­ های زیادی برای مدل‌سازی رفتار مکانیکی مصالح خاکی انجام شده است. فرض آن که پیش بینی رفتار خمیری خاک در برخی از مسائل مهندسی ارتباط زیادی با زمان ساخت ندارد باعث مغفول ماندن بعد زمان در بسیاری از مدل ­های رفتاری در ژئوتکنیک شده است. این در حالی است که خرابی­ های ناشی از نشست و یا ناپایداری گودبرداری ­ها و بسیاری مسائل دیگر از این دست به دلیل رفتار خمیری تابع زمان در خاک­ ها ایجاد می­ شود. همچنین در برخی پدیده ­ها همانند انفجار، زلزله و یا تحکیم مسئله زمان به شکل ذاتی مطرح است. از این رو نصب مدل رفتاری تابع زمان در کدهای اجزاء محدود که بتواند رفتار تابع زمان سازه­ ها در مهندسی ژئوتکنیک را به طور مناسبی پیش بینی نماید دارای اهمیت زیادی است. در این پژوهش یک مدل رفتاری الاستوپلاستیک – ویسکوپلاستیک از طریق سابروتین UMAT در کد اجزا محدود ABAQUS نصب شده است. این مدل با در نظر گرفتن رفتار غیر خطی الاستوپلاستیک – ویسکوپلاستیک از طریق مکانیزم­های سخت­ شوندگی سینماتیک و همسان بخش عمده­ای از محدودیت ­های مدل­ های رفتاری که تاکنون در کد ABAQUS نصب شده ­اند را مرتفع می­ سازد. نتایج حاصل از اعتبارسنجی تحت مسیرهای آزمایشگاهی مانند خزش، آسایش تنش و اثر نرخ حاکی از ظرفیت و قابلیت بالای مدل در پیش بینی رفتار تابع زمان خاک ­ها است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Implementation of an Elastoplastic–Viscoplastic Constitutive Model of Soil in ABAQUS Code and Its Validation on Laboratory Paths

نویسندگان [English]

  • seyed mohamad hashem bathayian 1
  • Mohammd Maleki 2
1 Buali-Sina university/Hamadan/Iran
2 Faculty of Engineering Bu-Ali Sina University
چکیده [English]

Many attempts have been made to model the mechanical behavior of soil materials. The assumption that predicting soil plastic behavior in some engineering problems doesn’t present a significant relation with construction time has led to the neglect of the time effect in many constitutive models in geotechnical engineering. However, damage due to settlement or instability of excavations and many other such problems are caused by the time-dependent plasticity behavior of soil. Also, in some phenomena such as explosions, earthquakes, or consolidation, the issue of time is inherently raised. Therefore, it is important to install a time-dependent constitutive model in finite element codes that can properly predict the time-dependent behavior of structures in geotechnical engineering. In this study, an elastoplastic-viscoplastic constitutive model via UMAT subroutine was implemented in the ABAQUS finite element code. By considering the nonlinear elastoplastic-viscoplastic behavior with mixed (kinematic and isotropic) hardening mechanisms, this model removes most of the limitations of the constitutive models already installed in the ABAQUS code. The results of validation under laboratory paths such as creep, relaxation and rate effect indicate the high capacity and capability of the model in predicting the time-dependent behavior of soil.

کلیدواژه‌ها [English]

  • Constitutive models
  • Elastoplastic–Viscoplastic
  • ABAQUS
  • Soil viscosity
  • Kinematic hardening

مراجع

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نشریه مهندسی عمران امیرکبیر
دوره 54، شماره 5
مرداد 1401
صفحه 2031-2050

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