Dr. Ismail Caylak

E. Penner, I. Caylak, R. Mahnken, in: Proceedings of the 2nd International Conference on Uncertainty Quantification in Computational Sciences and Engineering (UNCECOMP 2017), 2017

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2016

A Stochastic Finite Element Method with a Deviatoric-volumetric Split for the Stochastic Linear Isotropic Elasticity Tensor

R. Mahnken, I. Caylak, A. Dridger, A Stochastic Finite Element Method with a Deviatoric-volumetric Split for the Stochastic Linear Isotropic Elasticity Tensor (2016)

Abstract

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This paper presents a numerical method for solution of a stochastic partial differential equation (SPDE) for a linear elastic body with stochastic coefficients (random variables and/or random fields). To this end the stochastic finite element method (SFEM) is employed, which uses W IENER’S polynomial chaos expansion in order to decompose the coefficients into deterministic and stochastic parts. As a special case, we consider isotropic material behavior with two fluctuating parameters. Computational approaches involving GALERKIN projection are applied to reduce the SPDE into a system of deterministic PDEs. Furthermore, we consider normally distributed random variables, which are assumed to be stochastically independent, and which establish the number of stochastic dimensions. Subsequently, the resulting finite element equation is solved iteratively. Finally, in a representative example for a plate with a ring hole we study the influence of different variances for material parameters on the variances for the finite element results.

PC expansion for material parameters using artificial data and statistical methods

I. Caylak, N. Nörenberg, R. Mahnken, PAMM (2016), pp. 191-192

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A linear elastic Fuzzy Finite Element Method with two fuzzy input parameters

A. Dridger, I. Caylak, R. Mahnken, PAMM (2016), pp. 667-668

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SFEM for rubber-like materials at large deformations

E. Penner, I. Caylak, N. Nörenberg, R. Mahnken, PAMM (2016), pp. 675-676

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2015

Uncertainty quantification for linear elastic bodies with two fluctuating input parameters

A. Dridger, I. Caylak, R. Mahnken, PAMM (2015), pp. 551-552

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Non-linear Stochastic Finite Element

I. Caylak, A. Dridger, R. Mahnken, PAMM (2015), pp. 179-180

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2014

Experimental Investigation of PC-Films Using Optical Measurements

C. Dammann, I. Caylak, R. Mahnken, International Polymer Processing (2014), pp. 260-271

Abstract

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<jats:title>Abstract</jats:title> <jats:p>The alignment of polymer chains is a well known microstructural evolution effect due to straining of polymers. This has a drastic influence on the macroscopic properties of the initially isotropic material. In this work, cold forming is performed at room temperature on a tensile testing machine. Polycarbonate films are examined in two loading phases. In the first phase, the specimen is loaded to induce anisotropy, and in the second, it is re-loaded, while the material direction is varied. The investigations are supported by an optical measurement system to gain knowledge about the inhomogeneous material behavior in the initial loading phase and about the anisotropic homogeneous behavior during the re-loading phase. Two dimensional strain contours are obtained from the test data. Additionally, we propose a method for approximation of the macroscopic true stress and compare the results with a common approach based on volume consistency. In the future, the test data will set a basis for parameter identification of constitutive equations taking into account a combination of inhomogenous and homogenous material behavior, exhibiting strain induced anisotropy.</jats:p>

Stabilized mixed triangular elements with area bubble functions at small and large deformations

I. Caylak, R. Mahnken, Computers & Structures (2014), pp. 172-182

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