فهرست مقالات Beam Element

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  1 - Mass and Stiffness Matrices and Frequencies of Simple Beam Elements Based on Real Shape Functions
  Pedram Abouzari Karen Khanlari Reza Esmaeilabadi
  10.30486/admt.2022.1949656.1336
  In this research, we investigate and compare the natural frequencies of simple beams and their mass and stiffness matrices of the two methods: classic shape functions and real shape functions. To this end, we solve the beam motion Equation and apply boundary conditions. چکیده کامل

  In this research, we investigate and compare the natural frequencies of simple beams and their mass and stiffness matrices of the two methods: classic shape functions and real shape functions. To this end, we solve the beam motion Equation and apply boundary conditions. This article shows that the coefficients of the real shape functions, and consequently, the real shape functions, become harmonic and hyperbolic and also, they are dependent on the natural frequency value of the element. As a result, the real mass and the real stiffness matrix of each element are also dependent on the element frequency. The frequency values obtained from these two methods are compared with the exact frequency values of two simple beam types with different support conditions. In this way, we determine which method leads to more accurate and acceptable frequencies for these beams. Based on the obtained results, the percentage of frequency error obtained by the classical method is relatively high in the sample beams. Hence, the natural frequency value of the beams studied using exact shape functions shows a small error compared to the classical method in terms of the exact frequency value of these beams. It is of note that the frequency error obtained from the classical method is greater in the elements with a higher natural frequency. Overall, obtaining the exact natural frequency of an element will result in accurate dynamic responses and more appropriate analyses and designs. پرونده مقاله
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  2 - Analysis of Stresses in Helicopter Composite blade in Hovering Maneuver
  علی اصغر نادری محسن نظری
  The main purpose of this article is the structural analysis of a composite blade of a selected helicopter. In this study, the stresses on rotors' blades caused by centrifugal forces, lift, drag and torque are analyzed. The governing equations of the structure behavior a چکیده کامل

  The main purpose of this article is the structural analysis of a composite blade of a selected helicopter. In this study, the stresses on rotors' blades caused by centrifugal forces, lift, drag and torque are analyzed. The governing equations of the structure behavior and solving processes were carried out by MATLAB software, and simulation is carried out by ABAQUS software, and they are compared with each other. The program written for MATLAB is based on beam element theory and the computation of stress and displacement of considered elements of a blade, is one of the properties of the written code. In ABAQUS, the helicopter blade is simulated in various states such as composite and aluminum blade with/without web and composite blade with laminations in different angles. The results of the mentioned states are compared with each other and with the code and finally, the results are compared with reference article. Comparison between beam element results and ABAQUS simulation shows proper match. In order to optimize a composite blade, attention must be paid to factors such as, displacement and stress reduction and prevention of excess in weight, as by an increase in thickness of 45 and 90 degree laminates to 6.5 mm, maximum displacement would be 12.9 cm, and total weight of the structure would be 8 Kg. پرونده مقاله