Investigations on the Application of the Downhill-Simplex-Algorithm to the Inverse Determination of Material Model Parameters for FE-Machining Simulations

2021 ◽  
Vol 107 ◽  
pp. 102214
Author(s):  
M. Hardt ◽  
D. Schraknepper ◽  
T. Bergs
2021 ◽  
Vol 58 (1) ◽  
pp. 4-12
Author(s):  
Zuzana Vitková ◽  
Marián Tárník ◽  
Jarmila Pavlovičová ◽  
Anton Vitko ◽  
Jarmila Oremusová ◽  
...  

Abstract Micelles and micellization appeal long lasting interest as promising drug carriers. A conventional parameter providing information about formation of micelles is critical micelle concentration (cmc). Its value roughly separates two states of the surfactant solution – namely states with and without presence of micelles. If concentration of surfactants in water solution approaches cmc some physical quantities abruptly change, and this phenomenon is a key to determine value of the cmc. From numerous approaches for determination of the cmc the paper considers the conductivity-based method. But rather than studying the mechanism of micellization that is primarily carried out by the colloid chemists, the paper is focused on the development of an information rich and optimal dynamical model of the conductivity vs. concentration dependence. The model is derived from the solutions of the 1st order differential equation. The optimal model parameters are determined by the downhill simplex algorithm and the cmc is computed on the basis of the curvature of the concentration dependence of the conductivity.


2016 ◽  
Vol 250 ◽  
pp. 197-202 ◽  
Author(s):  
Michal Stopel Stopel ◽  
Dariusz Skibicki

Feasibility analysis of replacing split Hopkinson bars test by Charpy impact test for determination of Johnson-Cook’s material model parameters. The results show that the Charpy impact test may, due to the strain rates achieved, successfully replace the mentioned experimental test. Moreover the results shows that some further studies should be conducted to improve efficiency of the proposed method.


2011 ◽  
Author(s):  
A. Andrade-Campos ◽  
R. de-Carvalho ◽  
R. A. F. Valente

2012 ◽  
Vol 54 (1) ◽  
pp. 294-305 ◽  
Author(s):  
A. Andrade-Campos ◽  
R. de-Carvalho ◽  
R.A.F. Valente

Modelling ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 129-148
Author(s):  
Marvin Hardt ◽  
Deepak Jayaramaiah ◽  
Thomas Bergs

The manufacturing industry is confronted with increasing demands for digitalization. To realize a digital twin of the cutting process, an increase of the model reliability of the virtual representation becomes necessary. Thereby, different models are required to represent the experimental behavior of the workpiece material or frictional interactions. One of the most utilized material models is the Johnson–Cook material model. The material model parameters are determined either by conventional or by non-conventional material tests, or inversely from the cutting process. However, the inverse parameter determination, where the model parameters are iteratively modified until a sufficient agreement between experimental and numerical results is reached, is not robust and requires a high number of iterations. In this paper, an approach for the inverse determination of material model parameters based on the Particle Swarm Optimization (PSO) is presented. The approach was investigated by the inverse re-identification of an initial parameter set. The conducted investigations showed that a material model parameter set can be determined within a small number of iterations. Thereby, the determined material model parameters resulted in deviations of approximately 1% in comparison to their target values. It was shown that the PSO is suitable for the inverse material parameter determination from cutting simulations.


2005 ◽  
Vol 43 (sup1) ◽  
pp. 253-266 ◽  
Author(s):  
J. A. Cabrera ◽  
A. Ortiz ◽  
E. Carabias ◽  
A. Simón

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