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Non-linear finite element calculations are indispensable when important information of the material response under load of a rubber component is desired. Although the material characterization of a rubber component is a demanding engineering task, the changing contact range between the parts and the incompressibility behaviour of the rubber further increase the complexity of the investigations. In this paper the effects of the choice of the numerical material parameters (e.g. bulk modulus) are examined with regard to numerical stability, mesh density and calculation accuracy. As an example, a rubber spring is chosen where contact problem is also handled.

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Abstract  

The k 0-standardization method of neutron activation analysis (NAA) is very sensitive to the irradiation and counting time during measurement of the induced radionuclide by -spectrometry on the HP Ge detector. If the irradiation and counting time of the sample and co-irradiated standard is relatively short or the decay constant small, the application of the standard equation in the software for the specific count rate may become numerically unstable and the program aborts. In this work, attention is focused on the direct influence of saturation and "measurement" factors on the specific count rate for simple decay and for more complex types calculated directly by exponential functions, and by an alternative form using a truncated Taylor's series expression.

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Abstract

This paper presents a novel solution for shape optimization of compressed rubber parts. The procedure is based on the finite element method (FEM). A special purpose FEM code written in FORTRAN has been developed for the analysis of nearly incompressible axi-symmetric rubber parts. Numerical stability of the code and sensitivity analysis of the FEM input parameters are investigated. The aim of the parameter optimization is to reduce the time consuming FEM computations for the optimization process. The objective of the optimization is to find the optimal shape of the investigated rubber parts with a specified load-displacement curve. A regression model is used to determine the connection between the input and output data calculated by the FEM.

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Journal of Thermal Analysis and Calorimetry
Authors: Mihaela-Ligia Ungureşan, Andrada Măicăneanu, Francisc-Vasile Dulf, Eva-Henrietta Dulf, and Delia Maria Gligor

conceived so that it will be efficient and numerically stable. The modeling efficiency is ensured by the elaboration of some algorithms that will involve a small number of elementary arithmetical operations. The numerical stability of an algorithm refers to

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. (3) With the aim to get a numerical stability as well as limited dynamical range, the normalized Tchebichef polynomials were established: t ˜ n x = t n x β n N , β n N = N nr (4) where the β ( n , N ) stands for the suitable constant

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(sports) and .37 (race). Simultaneous entry of all predictors was not feasible due to deleterious effects on model degrees of freedom, multicollinearity, and numerical stability. Our first approach was to aggregate exposure to inducement and advertisement

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