Characterization of Material Properties Using Strain Mapping and Reverse Engineering

2006 ◽  
Author(s):  
Lianshan Lin ◽  
Haiyan Li ◽  
Alex S. L. Fok
Keyword(s):  
Finite Element ◽  
Reverse Engineering ◽  
Material Properties ◽  
Good Accuracy ◽  
Strain Mapping ◽  
Linear Elastic ◽  
Highly Nonlinear ◽  
User Material Subroutine ◽  
Failure Predictions

For simplicity, the material properties used in engineering analysis are often assumed to be linear elastic, isotropic and homogeneous. These simplifications may lead to erroneous stress and failure predictions if the materials involved are highly nonlinear, anisotropic and inhomogeneous. Based on the techniques of strain mapping and reverse engineering, a simple finite-element-based method has been devised with the aim of characterizing the properties of such materials under load. The method has been implemented into the commercial finite element code ABAQUS, via its User Material Subroutine (UMAT), to allow material characterization to be performed easily. Verification of the method has been carried out using simulated examples and the results showed rapid convergence of the method with good accuracy. The method has also been applied successfully to actual mechanical testing of graphite.

Characterization of Material Properties Using an Inverse Method

2006 ◽  
Vol 5-6 ◽  
pp. 107-114 ◽  
Author(s):  
Lianshan Lin ◽  
Haiyan Li ◽  
Alex S.L. Fok ◽  
Mark Joyce ◽  
T. James Marrow
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Material Characterization ◽  
Inverse Method ◽  
Good Accuracy ◽  
Inhomogeneous Distribution ◽  
Finite Element Code ◽  
Rapid Convergence ◽  
Porous Microstructure

A simple finite-element-based inverse method has been devised with the aim of characterizing the properties of isotropic but heterogeneous materials under load. The method has been implemented into the commercial finite element code ABAQUS via its User Material (UMAT) Subroutine to facilitate the process of material characterization. Verification of the method has been carried out using simulated examples and the results showed rapid convergence of the method with good accuracy. The method has also been applied successfully to actual mechanical testing of graphite which has a porous microstructure and hence inhomogeneous distribution of material properties.

Finite element simulation of folding carton erection failure

2007 ◽  
Vol 221 (7) ◽  
pp. 753-767 ◽  
Author(s):  
D M Sirkett ◽  
B J Hicks ◽  
C Berry ◽  
G Mullineux ◽  
A J Medland
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
High Speed ◽  
Element Model ◽  
Machine Material ◽  
Linear Elastic ◽  
Element Simulation ◽  
Packaging Industry ◽  
First Time ◽  
The Eu

In response to recent European Union (EU) regulations on packaging waste, the packaging industry requires greater fundamental understanding of the machine-material interactions that take place during packaging operations. Such an understanding is necessary to handle thinner lighter-weight materials, specify the material properties required for successful processing and design right-first-time machinery. The folding carton industry, in particular, has been affected by the new legislation and needs to realize the potential of computational tools for simulating the behaviour of packaging materials and generating the necessary understanding. This paper describes the creation and validation of a detailed finite element model of a carton during a common packaging operation. The model is applied here to address the problem of carton buckling. The carton was modelled using a linear elastic material definition with non-linear crease behaviour. Air inrush suction, which is believed to cause buckling, was quantified experimentally and incorporated using contact damping interactions. The results of the simulation are validated against high-speed video of carton production. The model successfully predicts the pattern of deformation of the carton during buckling and its increasing magnitude with production rate. The model can be applied to study the effects of variation in material properties, pack properties and machine settings. Such studies will improve responsiveness to change and will ultimately allow end-users to use thinner, lighter-weight materials in accordance with the EU regulations.

A Method for the Validation of Predictive Computations Using a Stochastic Approach

2004 ◽  
Vol 126 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Manuel Pellissetti ◽  
Roger Ghanem
Keyword(s):  
Finite Element ◽  
Finite Element Methods ◽  
Material Properties ◽  
Stochastic Approach ◽  
Stochastic Property ◽  
Limited Data ◽  
Bernoulli Beam ◽  
Direct Differentiation Method ◽  
Stochastic Properties

Stochastic finite element methods provide predictions of the behavior of mechanical systems with randomly fluctuating material properties. Limited data is typically available for the characterization of these properties, introducing errors in their representation. In the present paper, the sensitivity of the response predictions with respect to the stochastic properties is analyzed, by means of the direct differentiation method (DDM). Explicit expressions for the dependence of certain statistics of the response on the statistics of the material property are obtained. The response sensitivities are then used to estimate the error in the response predictions, caused by the error in the representation of the stochastic property. Numerical results for a simple Bernoulli beam are presented.

scholarly journals Material property and boundary condition effects on stresses in avalanche snow-packs

1974 ◽  
Vol 13 (67) ◽  
pp. 99-108 ◽  
Author(s):  
J. O. Curtis ◽  
F. W. Smith
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Stress Distribution ◽  
Computer Program ◽  
Material Properties ◽  
Shear Failure ◽  
Stress Distributions ◽  
Snow Pack ◽  
Snow Layer ◽  
Linear Elastic

A linear elastic finite element computer program was applied to determine the stress distributions in multi-layered snow-packs typical of those found at Berthoud Pass, Colorado. The effect on stress distribution of wide variations in elastic material properties was examined. Also, an attempt was made to model the shear failure of a weak sub-layer in the snow-pack by relaxing the condition that the bottom snow layer be firmly attached to the ground.

scholarly journals Inverse Calculation of Timber-CFRP Composite Beams Using Finite Element Analysis

2020 ◽  
Author(s):  
Khaled Saad ◽  
András Lengyel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Orthotropic Material ◽  
Material Model ◽  
Flexural Behavior ◽  
Fiber Reinforced Polymers ◽  
Element Analysis ◽  
Linear Elastic ◽  
Timber Beams

This study focuses on the flexural behavior of timber beams externally reinforced using carbon fiber-reinforced polymers (CFRP). Linear and non-linear finite element analysis were proposed and validated by experimental tests carried out on 44 timber beams to inversely determine the material properties of the timber and the CFRP. All the beams have the same geometrical properties and were loaded under four points bending. In this paper the general commercial software ANSYS was used, and three- and two-dimensional numerical models were evaluated for their ability to describe the behavior of the solid timber beams. The linear elastic orthotropic material model was assumed for the timber beams in the linear range and the 3D nonlinear rate-independent generalized anisotropic Hill potential model was assumed to describe the nonlinear behavior of the material. As for the CFRP, a linear elastic orthotropic material model was introduced for the fibers and a linear elastic isotropic model for the epoxy resin. No mechanical model was introduced to describe the interaction between the timber and the CFRP since failure occurred in the tensile zone of the wood. Simulated and measured load-mid-span deflection responses were compared and the material properties for timber-CFRP were numerically determined.

Evaluation of J Integral for Interacting Twin Collinear Through-Wall Cracks in a Plate under Tension

2015 ◽  
Vol 665 ◽  
pp. 97-100 ◽  
Author(s):  
Marko Katinic ◽  
Drazan Kozak ◽  
Ivan Samardzic ◽  
Antun Stoic ◽  
Zeljko Ivandic ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Material Properties ◽  
Strain Hardening Exponent ◽  
Fracture Parameter ◽  
The Finite Element Method ◽  
Single Crack ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Interaction Factor

The interaction behavior of twin collinear through-wall cracks in tension loaded plate under elastic-plastic condition is investigated by the finite element method (FEM). The fracture parameter J integral for interacting cracks is calculated and compared to the J integral for a single crack the same size. In this way, the interaction factor of cracks under elastic-plastic condition is defined. This interaction factor is compared to the results of analytical solution of the interaction factor under linear elastic condition. The results show that interaction factor of cracks under elastic-plastic condition is higher than interaction factor of same cracks under linear elastic condition. Also the interaction effect of cracks under elastic-plastic condition is influenced not only by the crack configurations but also by the material properties, especially the strain hardening exponent n.

scholarly journals Material property and boundary condition effects on stresses in avalanche snow-packs

1974 ◽  
Vol 13 (67) ◽  
pp. 99-108 ◽  
Author(s):  
J. O. Curtis ◽  
F. W. Smith
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Stress Distribution ◽  
Computer Program ◽  
Material Properties ◽  
Shear Failure ◽  
Stress Distributions ◽  
Snow Pack ◽  
Snow Layer ◽  
Linear Elastic

A linear elastic finite element computer program was applied to determine the stress distributions in multi-layered snow-packs typical of those found at Berthoud Pass, Colorado. The effect on stress distribution of wide variations in elastic material properties was examined. Also, an attempt was made to model the shear failure of a weak sub-layer in the snow-pack by relaxing the condition that the bottom snow layer be firmly attached to the ground.

scholarly journals Stochastic inverse finite element modeling for characterization of heterogeneous material properties

2019 ◽  
Vol 6 (11) ◽  
pp. 115806
Author(s):  
Carlos Llopis-Albert ◽  
Francisco Rubio ◽  
Francisco Valero ◽  
Hunchang Liao ◽  
Shouzhen Zeng
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Material Properties ◽  
Heterogeneous Material ◽  
Element Modeling

Swelling Characteristics of 3D-Arbitrary-Geometry of the pH-Sensitive Hydrogels

2013 ◽  
Author(s):  
Kamlesh J. Suthar ◽  
Derrick C. Mancini ◽  
Muralidhar K. Ghantasala
Keyword(s):  
Finite Element ◽  
Partial Differential Equations ◽  
Differential Equations ◽  
Material Properties ◽  
Ph Sensitive ◽  
Moving Mesh Method ◽  
Partial Differential ◽  
Highly Nonlinear ◽  
Simulation Results ◽  
Ph Sensitive Hydrogel

We present our simulation results of swelling responses of the pH-sensitive, 3D-arbitarary-geometry hydrogel in steady state conditions. The swelling responses of the hydrogels to the changes in environmental stimuli such as solution pH are discussed. The finite element simulation uses three nonlinear partial-differential equations for responsible physical phenomena namely- chemical for ionic transport across the hydrogel, electrical for local electric charge balance within hydrogel, and mechanical for expansion of the hydrogel by the Nernst-Planck, the Poisson’s, and the mechanical field equations respectively. In the case of pH-sensitive hydrogel, material properties such as modulus of elasticity and Poisson’s ratio changes with a change in surrounding environments. Finite element analysis used for present study was carried out by full coupling of above three partial-differential equations with variable material properties. Employing a moving mesh method for 3D geometry, the FEM simulation was performed to account for large-swelling of the pH-sensitive hydrogel. This highly nonlinear and computationally intensive simulation was performed using multicore parallel-processing computer. The simulation results using above mentioned strategy has been validated for 2D geometry and results are in agreement with other published experimental results.

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