Impact of Different Boundary Conditions on the Response of Glare Fiber-Metal Laminates under Lateral Indentation

2016 ◽  
Vol 25 (2) ◽  
pp. 096369351602500
Author(s):  
George S.E. Bikakis ◽  
Alexander Savaidis
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Modelling ◽  
Strain Energy ◽  
Tensile Fracture ◽  
Element Modelling ◽  
Different Boundary Conditions ◽  
Simply Supported ◽  
Modelling Procedure ◽  
Load Indentation

In this paper, a finite element modelling procedure is implemented in order to predict the static load-indentation curves and the defection shape of simply supported circular GLARE fibre-metal laminates subjected to lateral indentation by a hemispherical indentor. ANSYS software is used and a non-linear analysis is employed with geometric and material non-linearities for FEM calculations. The finite element modelling procedure is applied to GLARE 2–2/1–0.3 and to GLARE 3–3/2–0.4 simply supported circular plates with various diameters. It is found that the simply supported circular GLARE plates deform axisymmetrically from the beginning of the indentation process up to the point of their first failure due to glass-epoxy tensile fracture. By comparison of the obtained load-indentation curves to corresponding previously published load-indentation curves of clamped circular GLARE plates, the effect of the different boundary conditions on their lateral indentation response is studied. Furthermore, the strain energy-indentation curves of the considered circular GLARE 2 and GLARE 3 plates with simply supported and clamped boundaries are calculated and compared. It is found that the simply supported GLARE plates have reduced stiffness and demonstrate an increased first failure defection due to glass-epoxy tensile fracture versus the clamped GLARE plates, whereas the first failure load is not significantly affected by the different boundary conditions. It is also found that for the same lateral indentation, simply supported GLARE plates absorb lower strain energy levels than clamped GLARE plates. Referring to a specific lateral indentation level, the influence of the different boundary support on the corresponding indentation load and the absorbed strain energy is strong and can reach a deviation level of 45 % between the two support types. To our knowledge, a research concerning the response of simply supported GLARE plates under lateral indentation has not been published elsewhere.

Numerical Study of the Effect of Geometry and Boundary Conditions on the Collapse Behaviour of Stocky Stiffened Panels

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ultimate Strength ◽  
Material Properties ◽  
Finite Element Modelling ◽  
Numerical Study ◽  
Fe Analysis ◽  
Stiffened Panels ◽  
Element Modelling ◽  
Geometric Configurations

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

Finite Element Analysis of Polyurethane Based Composite Shafts Under Different Boundary Conditions

2014 ◽  
Author(s):  
Mosfequr Rahman ◽  
F. N. U. Aktaruzzaman ◽  
Saheem Absar ◽  
Aniruddha Mitra ◽  
Awlad Hossain
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Polymer Matrix ◽  
Three Dimensional ◽  
Woven Fabric ◽  
Bending Test ◽  
Matrix Composites ◽  
Fiber Glass ◽  
Different Boundary Conditions ◽  
Simply Supported

Depending on the type of matrix materials, composites can be broadly divided into three different major classifications: Organic-matrix composites (OMC), metal-matrix composites (MMC), and ceramic-matrix composites (CMC). OMC can be further sub-classified into polymer-matrix composites (PMC) and carbon-matrix composites or carbon-carbon composites. In this paper the main objective is to focus on polyurethane based PMC composites. Polyurethane is one of the widely used polymer matrix materials. It has diversified applications, easily available and cheap. In this computational study a composite shaft with a core made of matrix material completely wrapped around by a woven fiber cloth with a very strong bonding between core and fibers is considered. Three different types of woven fibers: fiber glass, Kevlar 49, and carbon fibers, are considered. A woven fabric is the interlocking or weaving of two unidirectional fibers. This configuration is often used to produce curve surfaces because of the ease with which it could be placed on and conform to curved surfaces. Authors had fabricated these three composites in their in-house laboratory. They had also experimentally measured the mechanical properties of these composites using 3-point bending test which already been published. In this current study finite element analyses has been performed for the modeling of the static response of these three different polyurethane based composite shafts as fiber glass reinforced polyurethane epoxy, carbon fiber reinforced polyurethane epoxy, and Kevlar fibers reinforced polyurethane epoxy for three different boundary conditions. These three boundary conditions are simply supported, cantilever, both end fixed types with bending loads applied at the middle for simply supported case and distributed load along the length of the shaft for the last two types of boundary conditions. A three dimensional model of the composite beam has been implemented in this study using SolidWorks. A finite element commercial software ANSYS is used to investigate the stress response and deformation behavior of the model geometry for these three polyurethane based composite shafts for these three boundary conditions. A twenty node three dimensional element has been implemented for the finite element formulation of the modeled geometry such that it is applicable for the analysis of a layered composite structure, while providing support for linear, large rotation, and large strain nonlinear loading conditions. Convergence has also been ensured for various mash configurations in this work.

scholarly journals Analytical and Finite Element Modelling of Circular Glare Plates under Indentation Loading and Unloading

2011 ◽  
Vol 20 (4) ◽  
pp. 096369351102000 ◽  
Author(s):  
George J. Tsamasphyros ◽  
George S. Bikakis
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Circular Plates ◽  
Element Modelling ◽  
Modelling Procedure ◽  
Static Indentation ◽  
Analytical Formulas ◽  
Loading And Unloading ◽  
Analytical Expressions ◽  
Dent Depth

In this paper, analytical expressions are derived and a finite element modelling procedure is proposed in order to predict the static load-indentation curves of circular GLARE fibre-metal laminates during loading and unloading by a hemispherical indentor. Analytical formulas have been recently published for the static indentation of circular GLARE plates which are now used during the loading stage. Here, considering that aluminum layers are in a state of membrane yield and employing energy balance during unloading, the unloading path is determined. Using this unloading path, an algebraic equation is derived and solved for calculating the permanent dent depth of the GLARE plate after the indentor's withdrawal. ANSYS software is used and a non-linear analysis is employed with geometric and material non-linearities for FEM calculations. The derived formulas and the proposed finite element modelling procedure are applied to GLARE 2-2/1-0.3 and to GLARE 3-3/2-0.4 circular plates. The analytical results are compared with corresponding FEM results and a good agreement is found. The analytically calculated permanent dent depth is within 6 % for the GLARE 2 plate, and within 7 % for the GLARE 3 plate, of the corresponding numerically calculated result. No other solution of this problem is known to the authors.

Relaxation in Sub-Micron Si-1-xGex Strain-Layer Mesas

1991 ◽  
Vol 239 ◽  
Author(s):  
Dawei Luo ◽  
David J. Howard ◽  
David C. Paine
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Strain Energy ◽  
Critical Thickness ◽  
Thick Layer ◽  
Si Substrate ◽  
Misfit Stress ◽  
Plan View ◽  
Element Modelling ◽  
Strain Layer

ABSTRACTFinite element modelling of strain-layer mesa structures shows that edge effects can contribute to the relaxation of in-plane misfit stress. Calculations were performed for a 200 nm thick layer of Si90Ge10 grown epitaxially on an <001> Si substrate which was patterned into 400-nm-high mesas ranging in diameter from 0.6 to 7 μm. These calculations were experimentally investigated using plan-view TEM to study relaxation in patterned and unpatterned material. This composition and film thickness exceeds the critical thickness predicted using simple strain energy considerations. In one experiment, an initially defect-free 200-nm-thick Si90Ge10 layer was annealed at 960°C for 1 hr to create a nearly fully relaxed layer which was then lithographically patterned into an array of sub-micron mesas. The wafer was then annealed for a second time and changes in the character of die pre-existing dislocations were studied.

Application of Finite Element Method for Nonlinear Analysis in Reinforced Concrete Structures

2012 ◽  
Vol 166-169 ◽  
pp. 935-938
Author(s):  
Ming Rong Zhou
Keyword(s):  
Finite Element ◽  
Nonlinear Analysis ◽  
Finite Element Modelling ◽  
Concrete Beam ◽  
Constitutive Relationship ◽  
Element Modelling ◽  
Simply Supported ◽  
Computation Process ◽  
Concrete Materials ◽  
Experimental Values

Finite Element modelling (FEM) has been expounded with the introduction of concrete materials constitutive relationship model.Meanwhile, bearing capacity of simply supported concrete beam is simulated by adopting FEM software-ANSYS through the whole computation process. Moreover, results of computed values and experimental values are compared demonstrating that related nonlinear analysis and treatment can be done well in this approach.

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