مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

پایداری تیر دوار ساخته شده از فرامواد فوق سبک تحت نیروی پیرو گسترده

نوع مقاله : مقاله پژوهشی

نویسندگان
دانشکده مهندسی مکانیک، دانشگاه شیراز، شیراز، ایران
10.48311/mme.2025.96869.0
چکیده
امروزه به‌کارگیری مواد نوین در سازه‌های هوایی مانند ملخ‌ها، امری حیاتی در صنعت هوافضا به‌شمار می‌رود. از سوی دیگر، فرامواد فوق‌سبک با قابلیت کاهش وزن سازه، توجه زیادی را به خود جلب کرده‌اند. بنابراین، بررسی پایداری سازه‌های هوایی تحت نیروهای ناپایستار مانند نیروی پیرو که معمولاً به‌عنوان مدل ساده‌سازی شده اثر اندرکنش سیال و سازه شناخته می‌شود ضروری است. در این مقاله، پایداری تیر دوار تیموشنکو تحت نیروی پیرو گسترده یکنواخت و شرط مرزی یکسرگیردار مورد بررسی قرار گرفته است. تیر دارای ساختار ساندویچی با هسته‌ای از فرامواد فوق‌سبک است و معادلات حاکم بر تیر با استفاده از اصل همیلتون استخراج شده‌اند. برای تحلیل عددی از روش تربیع دیفرانسیل (DQM) استفاده شده و نتایج با مطالعات پیشین مقایسه شده‌اند. چهار نوع ساختار هسته شامل مربعی، شش‌ضلعی، مثلثی و ترکیبی مورد بررسی قرار گرفته و تأثیر آن‌ها بر نیروی بحرانی تیر تحلیل شده است. نتایج نشان داد که در میان ساختارهای فرامواد بررسی‌شده، ساختار شش‌ضلعی عملکرد بهتری نسبت به سایر ساختارها دارد. همچنین، بر اساس نتایج بدست آمده، کاربرد فرامواد در هسته تیر ساندویچی باعث افزایش نیروی بحرانی به ازای وزن واحد می‌شود. علاوه بر آن، افزایش اثرات برشی در تیرهای کوتاه و نیز اثر دوران تیر، تأثیر ساختار هسته را در افزایش نیروی بحرانی نسبت به تیر غیر دوار کاهش می‌دهد؛ در نتیجه، در هر دو حالت سرعت‌های دورانی بالا و طول تیر زیاد، نیروی بحرانی تیر ساندویچی و تیر یکنواخت تقریباً یکسان می‌شود.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Stability of Rotating Beam Made of Ultra-light Metamaterials Subjected to Distributed Follower Force

نویسندگان English

Mohammad Tashakorian
S.Ahmad Fazelzadeh
Esmael Ghavanloo
School of Mechanical Engineering, Shiraz University, Shiraz, Iran
چکیده English

Today, the implementation of new materials in aero-structures such as propellers is crucial in the aeronautical industry. Also, ultralight metamaterials with capabilities to reduce the weight of the structure have received much interest. Therefore, it is essential to investigate the stability of aero-structures under non-conservative forces such as the follower force, which is generally considered as the fluid-structure interaction effect. In this paper, the stability of the rotating Timoshenko beam subjected to distributed follower force with clamped-free boundary condition is investigated. The beam consists of a sandwich structure and the core is made of ultralight metamaterials. The governing equations of the beam are derived using Hamilton's principle. For numerical analysis, the differential quadrature method (DQM) is used and the results are compared with those obtained from previous studies. Four core structures including square, hexagonal, triangular, and mixed are studied and their effects on the critical force of the beam are studied. The results showed that among the studied metamaterial structures, hexagonal structure has a better performance than other structures. Also, based on the numerical results, the use of metamaterials as the core of the sandwich beam increases the critical force per unit weight. In addition, the increase in shear effects in short beams and the effect of beam rotation reduces the effects of the core structure in increasing the critical force compared to the non-rotating beam; therefore, at high rotational speeds and long beams, the critical force of the sandwich beam and the uniform beam are quite the same

کلیدواژه‌ها English

Rotating Timoshenko Beam, Distributed Follower Force, Ultra-Light Metamaterials, Stability, DQM
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