فهرست مقالات Free vibration analysis

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  1 - A Novel Spring-Based Model for Damage Investigation of Functionally Graded Beams
  S Karimi M Bozorgnsab R Taghipour M.M Alipour
  10.22034/jsm.2021.1928249.1690
  In this paper, free vibration analysis of damaged functionally graded beams based on the first-order shear deformation theory (FSDT) is carried out. In this regard, a new model of springs is introduced to model the damaged elements of the beam. The proposed model is ach چکیده کامل

  In this paper, free vibration analysis of damaged functionally graded beams based on the first-order shear deformation theory (FSDT) is carried out. In this regard, a new model of springs is introduced to model the damaged elements of the beam. The proposed model is achieved from stress resultants. The springs equations for homogeneous and functionally graded (FG) beams are presented; furthermore, equations for equivalent springs are also provided which can be used for both homogeneous and FG beams. The proposed method can be applied for the analysis of structures with fewer computation costs and high accuracy. To show the accuracy of the proposed model, the natural frequencies of the beams with real elements and the ones which are modeled by the proposed springs are compared considering various support conditions. Good agreement has been observed. Thereafter, the model is used to detect the damaged elements. The result shows that the model can properly detect the damage location. پرونده مقاله
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  2 - تحلیل ارتعاشات و کنترل میکروتیر یکسر گیردار به همراه لایه های عملگر و حسگر پیزوالکتریک با فرض اثرات سطح
  سید علی افتخاری محمد خواجه خباز محمد هاشمیان
  امروزه پیش‌بینی رفتار ارتعاشی و دینامیکی سازه‌های میکرو مورد توجه بسیاری از پژوهشگران قرار گرفته است. در این پژوهش تحلیل ارتعاشات و کنترل میکروتیر یکسر گیردار به همراه لایه‌های پیزوالکتریک عملگر و حسگر با فرض اثرات تنش سطح مورد ارزیابی قرار گرفته است. معادلات دیفرانسیل چکیده کامل

  امروزه پیش‌بینی رفتار ارتعاشی و دینامیکی سازه‌های میکرو مورد توجه بسیاری از پژوهشگران قرار گرفته است. در این پژوهش تحلیل ارتعاشات و کنترل میکروتیر یکسر گیردار به همراه لایه‌های پیزوالکتریک عملگر و حسگر با فرض اثرات تنش سطح مورد ارزیابی قرار گرفته است. معادلات دیفرانسیل حاکم با استفاده از روش انرژی و اصل همیلتون استخراج شده و از روش مجموع مربعات دیفرانسیلی تعمیم یافته برای گسسته-سازی و تبدیل معادلات دیفرانسیل پاره‌ای به دسته معادلات دیفرانسیل معمولی استفاده شده است. اثر تغییرات هندسه مدل و مدول الاستیسیته سطح، تنش پسماند سطح و چگالی سطحی بر فرکانس طبیعی مدل میکروتیر با لایه‌های پیزوالکتریک بررسی شده است. همچنین تأثیر طراحی کنترلر بهینه خطی بر تغییرات پاسخ دینامیکی و ولتاژ کنترلی پیزوالکتریک مورد ارزیابی قرار گرفته است. نتایج نشان دهنده‌ی افزایش سرعت پاسخ و کاهش سریعتر دامنه ارتعاشی مدل با طراحی کنترل بهینه خطی است. پرونده مقاله
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  3 - Free vibration analysisof soft-core composite-faced sandwich plates using three-dimensional finite element method
  Mohammad Mahdi Kheirikhah Hasan Aghabarati Pooneh Khosravi
  In this paper, natural frequencies of the sandwich plates with soft flexible core and composite face sheets are obtained. Three-Dimensional (3D) finite element method (FEM) is used for constructing and analyzing of the sandwich plates to obtain their natural frequencies چکیده کامل

  In this paper, natural frequencies of the sandwich plates with soft flexible core and composite face sheets are obtained. Three-Dimensional (3D) finite element method (FEM) is used for constructing and analyzing of the sandwich plates to obtain their natural frequencies. Continuity conditions for transverse shear stresses at the interfaces as well as transverse flexibility and transverse normal strain and stress of the core are considered.The effects of plate dimensions such as aspect ratio and thickness ratio are studied. Also, different boundary conditions such as all edges clamped (CCCC), all edges simply supported (SSSS) and combined boundary conditions including (CFCF)are applied to the sandwich plates. Comparison of the present results in special case with those of the accurate plate theories confirms the accuracy of the proposedmodel. پرونده مقاله
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  4 - Formulation of a new finite element based on assumed strains for membrane structures
  Lahcene Fortas Lamine Belounar Tarek Merzouki
  10.30495/ijase.2019.705775
  AbstractIn this paper, a new triangular membrane finite element with in-plane drilling rotation has been developed using the strainbasedapproach for static and free vibration analyses. The proposed element, having three degrees of freedom at each of thethree corner node چکیده کامل

  AbstractIn this paper, a new triangular membrane finite element with in-plane drilling rotation has been developed using the strainbasedapproach for static and free vibration analyses. The proposed element, having three degrees of freedom at each of thethree corner nodes, is based on assumed strain functions satisfying both compatibility and equilibrium equations. Numericalinvestigations have been conducted using several tests, including static and free vibration problems, and the obtained resultsare compared with analytical and numerical available solutions. It is found that efficient convergence characteristics andaccurate results can be achieved using the developed element. پرونده مقاله
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  5 - Free Vibration Analysis of Sandwich Micro Beam with Piezoelectric Based on Modified Couple Stress Theory and Surface Effects
  Mohammad khajekhabaz Ali Eftekhari Mohammad Hashemian
  In this paper, the free vibration analysis of sandwich micro beam with piezoelectric layers based on the modified couple stress and surface elasticity theories are investigated. The Hamilton’s principle is employed to derive the sandwich micro beam with piezoelect چکیده کامل

  In this paper, the free vibration analysis of sandwich micro beam with piezoelectric layers based on the modified couple stress and surface elasticity theories are investigated. The Hamilton’s principle is employed to derive the sandwich micro beam with piezoelectric based on modified couple stress theory incorporating with Gurtin- Murdoch surface theory. The generalized differential quadrature method is used to discretize the partial differential equation into the ordinary differential equation. The effect of various parameters such as thickness to material length scale parameter ratio, the surface residual stress, Young's modulus of surface layer, surface mass density and surface piezoelectric constant are investigated by comparing the results obtained using the modified couple and classical theories. Numerical results of this problem evaluate the effect of micro length scale parameters on natural frequency. The results show that surface parameter effects are significant when the model is small, but can be neglected with increasing model size. پرونده مقاله