FEM. Optimization Analysis on Laminated Composite Plates with FSDT (update:07-23-07)

Umut TOPAL & Ali ÖZGÜL (16.03.07-21.07.07)

FINITE ELEMENT ANALYSIS on LAMINATED COMPOSITE PLATES with FIRST-ORDER-SHEAR DEFORMATION THEORY (FSDT)

Objective of this Matlab's program was researched optimization analysis of laminated composite plates for determined the ultimate strength and stress effects of plate's under the regular and uniform out-loads. Therefore, generally Reissner's flat and thick shell finite element model (4Node-20Dof) was developed with first-order shear deformation theory (FSDT).

Kirchhoff's classical laminate plate theory yields in adequate results for thick plates (a/th<20). This classical laminated plate (CLPT or CPT), was one of the first developed by Reissner with shear deformation theory. Afterwards, Mindlin was utulizated this shear deformation theory to accommodate rotary of inertia terms on per unit freedom. If this plate system's be very thick (a/th<10) than it is fail to shear deformation-motion and it's condition of adaptive shear stress on plate's top and bottom surface.

While this conditions was produced on plate's segment when requered the shear correction factor of shear locking effect-motion. In this sub-program is possible the optimization analysis with shear locking effect. But, this analysis was selected simple the stiffness reduction technique.

Stiffness reduction method:Integrated system stiffness matrix's non-shear cosponents with 3x3 Gauss-Legendre-Quadratix method and

it's shear cosponents with 2x2 Gauss-Legendre-Quadratix method. Plainly this Matlab programs are not consider high-order-level shear locking effects and selected all stiffness terms (non-shear or with shear) 3x3 Gauss-Quadratic integration technique.

EXAMPLE

[optimizationangle,FI]=Epox4.m <---|

teta1=0 ;
teta2=90 ;
rho=1/50 ;
tetarandom=pi/180*[ loc ]
segment=1;

anglestart--anglestop--anglestep---rho--minimumangle---FI----Error
b/h=20
a/b=1.0 0.0000 90.0000 0.9000 0.0100 45.0000 0.0960 0.0003
a/b=1.5 0.0000 90.0000 0.9000 0.0100 41.4000 0.0786 0.0000
a/b=2.0 0.0000 90.0000 0.9000 0.0100 39.6000 0.0670 0.0000
a/b=2.5 0.0000 90.0000 0.9000 0.0100 38.5000 0.0576 0.0000

AUTHORS

Umut TOPAL:
Doctorate-researcher
umuttopal61@hotmail.com
Department of Civil Engineering,BlackSea Technical University,
61080 Trabzon, Turkey

Ali ÖZGÜL:
High-Civil Engineer
alvortex@hotmail.com
BlackSea Technical University & Samsun 19 May University.