scholarly journals Optimization of a rectangular plate piecewise constant thickness when bending, prepared from the composite material.

2012 ◽  
Vol 65 (1) ◽  
pp. 35-42
Author(s):  
E.V. Belubekyan ◽  
A.G. Poghosyan ◽  
H.R. Avetisyan
Keyword(s):  
Composite Material ◽  
Rectangular Plate ◽  
Constant Thickness ◽  
Piecewise Constant

Optimal design of a cylindrical composite panel of piecewise constant thickness

2017 ◽  
Vol 13 (4) ◽  
pp. 568-577 ◽  
Author(s):  
Ernest Belybekyan ◽  
Arevshat Poghosyan ◽  
Hayk Sharkhatunyan
Keyword(s):  
Optimal Design ◽  
Optimal Choice ◽  
Composite Panel ◽  
Constant Thickness ◽  
Physical Parameters ◽  
Strength Increase ◽  
Constant Weight ◽  
Content Type ◽  
Piecewise Constant ◽  
Fixed Weight

Purpose The purpose of this paper is to investigate the problem of optimizing geometrical and physical parameters of a stepped shell that maximize its rigidity and strength for given overall shell dimensions and fixed weight equal to the weight of a shell of constant thickness. Design/methodology/approach A mathematical model of the construction’s stress-strain state is described by solving a system of differential equations for each of the constituent parts of the shell, conjugation conditions on the division lines and boundary conditions. The stated optimization problem is reduced to a nonlinear programming problem, which is solved by the deformable polyhedron method in combination with the method of direct search and using the parallel computing package in the Wolfram Mathematica software application. Findings As follows from the results of the calculation, optimizing the shell parameters allows for a substantial increase in rigidity (decrease of the greatest deflection) and strength (increase of the load-carrying capacity) of the shell of constant stepwise thickness, as opposed to a shell of constant thickness, with constant weight and dimensions. Originality/value A problem of optimal design of a cylindrical composite panel of piecewise constant thickness is solved in the presented work. Numerical examples demonstrate that a substantial increase in rigidity and strength of a stepped composite shell can be achieved by the optimal choice of its geometrical and physical parameters.

Analysis of Stresses and Displacements of Thin Coating Structures

2017 ◽  
Vol 887 ◽  
pp. 41-45
Author(s):  
Elena Sima ◽  
George Bălan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Organic Polymer ◽  
Constant Thickness ◽  
Thin Coating ◽  
Polymer Fiber ◽  
The Finite Element Method ◽  
Thin Coatings ◽  
Structural Research

This paper addresses the problem of open thin coatings of constant thickness made from Kevlar composite material. Kevlar is an organic polymer fiber 5 times stronger than steel taken at the same weight. Therefore, this fiber has been used successfully in producing composite materials. In this paper, the generic name of Kevlar designates the composite material having the following characteristics: E=7,6×104MPa; θ=0,34; ρ=1700kgcm3. The program COSMOS/M with which the study was conducted and broadcasted was The Structural Research and Analysis Corp. The analysis was carried out by the finite element method.

Vibration analysis of non-uniform porous beams with functionally graded porosity distribution

2018 ◽  
Vol 233 (8) ◽  
pp. 1678-1697
Author(s):  
M Heshmati ◽  
F Daneshmand
Keyword(s):  
Mathematical Formulation ◽  
Beam Theory ◽  
Considerable Change ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Constant Thickness ◽  
Thickness Variation ◽  
Porosity Distribution ◽  
Piecewise Constant ◽  
Modes Of Vibration

In this paper, the effect of different profile variations on vibrational properties of non-uniform beams made of graded porous materials is studied. Timoshenko beam theory is used to present the mathematical formulation of the problem including shear deformation, rotary inertia, non-uniformity of the cross-section, and graded porosity of the beam material. Three different variations of porosities through the thickness direction are introduced. The beam is assumed with the clamped condition at both ends. To obtain a numerical solution, finite element formulations of the governing equations are presented. The non-uniform beam is approximated by another beam consisting of n elements with piecewise constant thickness to keep the volume and hence the total mass unchanged for each element. The beam response has been calculated for the first three modes of vibration. In each case, the results for different types of thickness variation and porosity distribution are compared with those obtained for a beam with uniform thickness. The effects of non-uniformity, taper parameters, and porosity distribution on the frequencies and mode shapes are investigated. It is observed that a considerable change in frequencies and mode shapes can be achieved by selection of different thickness variation and porosity distribution.

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