بررسی روش نگاشت نمایی یک‌چهارم گام برای تابع‌اولیه‌گیری از مومسانی وان- مایسز

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشگاه صنعتی قوچان

چکیده

به ­هنگام ­سازی تنش در تحلیل اجزای محدود ناخطی مواد، مهم­ترین قسمت تحلیل می ­باشد، زیرا به­ طور قابل‌توجهی بر دقت پاسخ‌های به ­دست ­آمده اثرگذار است. با‌توجه به این‌که دقت و زمان دو عامل کلیدی در کارایی روش­های تابع ­اولیه­ گیری هستند، بررسی دقت و عملکرد این روش­ها اهمیت بسیاری دارد. در این پژوهش، الگوی مومسانی وان- مایسز با سخت­شوندگی­های خطی همگن و پویا در محدوده تغییرشک ل­های کوچک درنظر گرفته می­شود. باید دانست در حل دستگاه معادله­ های دیفرانسیل مومسانی به‌روش نیمه ­ضمنی رویکرد رایج این‌گونه است که متغیرهای مورد نیاز تحلیل از میانه گام مومسانی برداشت شود. به‌منظور بررسی دقت در این پژوهش رابطه ­سازی­ها به‌گونه ­ای انجام شده‌است که بتوان متغیرها را از یک­ چهارم گام مومسانی برداشت نمود. درپایان، با انجام آزمون­های عددی، دقت پاسخ­ های به­ دست ­آمده از این حالت بررسی می‌شود و با حالت رایج مقایسه می­ گردد.

کلیدواژه‌ها


عنوان مقاله [English]

Verification of Quarter-step Exponential Map Method for Integration of Von-Mises Plasticity

نویسندگان [English]

  • Nader Haji Aghajanpour1
  • Mehrzad Sharifian
  • Mehrdad Sharifian
Quchan University of Technology
چکیده [English]

Updating stress in a nonlinear finite element analysis is the most important part as the precision of the stress-updating algorithm greatly affects the accuracy of the final solutions.The most important part of the analysis is the stress-updating. There are two key factors that have impact on the efficiency evaluation; those are the accuracy and time. Based on this point, investigating the accuracy of the integration methods becomes important. In this study, the von-Mises plasticity model along with the linear isotropic and kinematic hardening mechanisms is considered in the small strain realm. In solving the plasticity differential equations system through a semi-implicit method, the prevalent approach is picking up the variables from the middle of the plasticity step. In order to assess the accuracy, here, the relations are derived so that one can pick up the variables from the first quarter of the plasticity step. Finally, to determine the accuracy and comparing two aforementioned methods, the numerical tests are performed.

کلیدواژه‌ها [English]

  • Stress updating
  • semi-implicit method
  • von-Mises plasticity
  • isotropic hardening
  • kinematic hardening
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