The use of Morris method in sensitivity analysis of a numerical model of solidification

• Autorzy: Sczygiol N. , Dyja R.

Warianty tytułu

PL

Zastosowanie metody Morrisa do analizy wrażliwości numerycznego modelu krzepnięcia

• Konferencja: 14th KomPlasTech Conference, Zakopane, January 14-17, 2007
• Języki publikacji: EN

Abstrakty

EN

Numerical models which are created nowadays can be characterised by a high degree of complication. This complication concerns mainly big number of parameters of a model. As it turns out, not all parameters have equal influence on received results. Some of parameters have dominant influence, whereas influence of the other parameters is marginal and can be neglected with success. This means that part of parameters which are costly to determine and determination of which can require long-lasting research can be skipped in a given model without large influence on received results. And vice versa: some parameters which have dominant influence on results should be specified with the highest possible precision. Sensitivity analysis deals with the task of division of these parameters with regard on received results. In the sensitivity analysis we can distinguish between a local approach as well as a global approach. In case of the local approach the task is to investigate the influence of changes of individual parameter on received results with an assumption of unchangeability of other parameters. On the other hand, the global approach implies that the values of remaining parameters undergo changes, too. Many methods, varying among other things in computational time, belong to the global sensitivity analysis. The presented work concentrates on global sensitivity analysis, and particularly on one of method which belongs to global sensitivity analysis methods. Method used in this work is known in literature as Morris method. The most important feature of Morris method is its cheapness, which means the possibility to obtain the results with comparatively small effort of calculations. This feature enables its usage in case of models requiring qualification of many parameters, as well as in case when the models require many calculations. Such a situation takes place in case of numerical modelling of solidification process. And for this reason Morris method was decided to be used in sensitivity analysis of numerical model of solidification, because numerical modelling of solidification requires long time of calculations. In the presented work a solver that is part of Nuscas system is analysed. Nuscas is developed in the Institute of Computer and Information Sciences at Czestochowa University of Technology. The solver, which is used in numerical simulation of solidification process makes it possible to choose between explicit capacity and basic enthalpy formulation. It is also possible to choose the model of solid phase growth from models of equilibrium, nonequilibrium and intermediate growth of solid phase. The executed sensitivity analysis permits to rank given parameters with respect to their influence on received results. That knowledge allows distinction of particularly important parameters, as well as these parameters, which have little influence.

PL

W przedstawionej pracy zamieszczone jest omówienie analizy wrażliwości numerycznego modelu krzepnięcia za pomocą metody Morrisa. Analiza wrażliwości pozwala na badanie wpływu poszczególnych parametrów na uzyskiwane wyniki. Pozwala to ustalić parametry, które mają znaczny wpływ na wyniki, jak również te, których wpływ jest niewielki. Metoda Morrisa jest szczególnie przydatna do badania modeli, wymagających dużego nakładu obliczeń lub są opisane dużą liczbą parametrów, z powodu niewielkiej wymaganej przez nią wyk nanych symulacji komputerowych. Analiza wrażliwości numerycznego modelu krzepnięcia opracowanego przez autoró pracy jest przedstawiona jako przykład zastosowania metody Morrisa.

Słowa kluczowe

EN

sensitivity analysis; Morris method; computer experiment; fmite element method; solidification model

• Wydawca: Wydawnictwa AGH
• Czasopismo: Computer Methods in Materials Science
• Rocznik: 2007
• Tom: Vol. 7, No. 2
• Strony: 250--254
• Opis fizyczny: Bibliogr. 5 poz., rys.

Twórcy

autor

Sczygiol N.

autor

Dyja R.

• Częstochowa University of Technology, Institute of Computer and Information Sciences,

Bibliografia

• Campologno, F., Saltelli A., 1997, Sensitivity analysis of an environmental model: an application of different analysis methods, Reliability Engineering and System Safety, 57, 49-69.
• Morris, M. D., 1991, Factorial Sampling Plans for Preliminary Computational Experiments, Technometrics, 33, 161-174.
• Saltelli, A., Tarantola, S., Campologno, F., Ratto, M., 2004, Sensitivity analysis in practice: a guide to assessing scientific models, John Wiley & Sons, Chichester.
• Sczygiol, N., 2000, Modelowanie numeryczne zjawisk termomechanicznych w krzepnącym odlewie i formie odlewniczej, Wyd. Politechniki Częstochowskiej, Częstochowa (in Polish).
• Tomlin, A.S., 2006, The use of global uncertainty methods for the evaluation of combustion mechanism, Reliability Engineering and System Safety, 91, 1219-1231.