scholarly journals Elastic Behavior of Lay-Ups Angles of Laminated Composite Beam with Material Property Grading

2021 ◽  
Vol 10 (9) ◽  
pp. 44-51
Author(s):  
Saeed Asiri ◽  
Keyword(s):  
Natural Frequency ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Laminated Composite ◽  
Elastic Behavior ◽  
Layer By Layer ◽  
Composite Shells ◽  
The Difference ◽  
Laminated Composite Beam ◽  
6 Degrees Of Freedom

The article discusses the study of Vibration Analysis of Generally layered Graphite-Epoxy with lay-up [300 /500 /300 /500 ]. The finite element method is utilized in the study, to analyze the effect of lay-up on the natural frequency and comparing the results with the article[1]. Method: The study is done using Ansys. Graphite-epoxy is considered for the study. The model is prepared from SHELL 281 element which is well-suited for composite shells and sandwiched construction. The accuracy in modeling composite shells is governed by the first-order MindlinReissner shell theory. The element has 8 nodes with 6 degrees of freedom at each node translations in the x, y, and z axes, and rotations about the x, y, and z-axes respectively. Finding: The study concludes that the values of natural frequency decreased when increased the difference between angles of lay-up. Novelty/Applications: Vibration Analysis study has been done in aspects, like sandwiched beam in which different materials are sandhwiched in a layer by layer fashion. Many studies also covers composite material with lay-up in great detail, but there is acute study about the comparision of the different lay-up angles at given boundary condition. These articles cover the same at a greater extent, and conclude that the strength and capacity of composite beams can be enhanced not only by blending composites together, but also giving importance to the arrangement of layers of composite materials.

Workspace, dexterity and dimensional optimization of microhexapod

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Screw Theory ◽  
Design Parameters ◽  
Dimensional Synthesis ◽  
Content Type ◽  
Workspace Analysis ◽  
The Difference ◽  
Flexure Joints ◽  
6 Degrees Of Freedom

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.

scholarly journals Finite Element Vibration Analysis of Laminated Composite Folded Plate Structures

1999 ◽  
Vol 6 (5-6) ◽  
pp. 273-283 ◽  
Author(s):  
A. Guha Niyogi ◽  
M.K. Laha ◽  
P.K. Sinha
Keyword(s):  
Finite Element ◽  
Forced Vibration ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Laminated Composite ◽  
Mode Shapes ◽  
Plate Structures ◽  
Drilling Degree Of Freedom ◽  
Vibration Responses ◽  
Forced Vibration Analysis

A nine-noded Lagrangian plate bending finite element that incorporates first-order transverse shear deformation and rotary inertia is used to predict the free and forced vibration response of laminated composite folded plate structures. A 6 × 6 transformation matrix is derived to transform the system element matrices before assembly. The usual five degrees-of-freedom per node is appended with an additional drilling degree of freedom in order to fit the transformation. The present finite element results show good agreement with the available semi-analytical solutions and finite element results. Parametric studies are conducted for free and forced vibration analysis for laminated folded plates, with reference to crank angle, fibre angle and stacking sequence. The natural frequencies and mode shapes, and forced vibration responses furnished here may serve as a benchmark for future investigations.

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