commit:2019:04_05
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====== Commit 2019-05-04 ====== | ====== Commit 2019-05-04 ====== | ||
===== Stabilization of the “Souza” method in ContinuousDamageEvpIsoHHypoMaterial===== | ===== Stabilization of the “Souza” method in ContinuousDamageEvpIsoHHypoMaterial===== | ||
+ | Some test cases using the " | ||
+ | |||
+ | To solve this problem I first checked the implementation of all the equations and found no mistakes. | ||
+ | |||
+ | I concluded that the problem might be purely numerical so I tried to improve the code and made the following changes: | ||
+ | |||
+ | 1) I changed the computation of the derivative of the residue with respect to deltaR (effective plastic strain increment) to compute seperately the term relative to the damage (dResD) and to the damage evolution function (dResDD). Those two terms having different order of magnitude in the case where the damage should not change, this should result in less numerical errors. | ||
+ | |||
+ | 2) I changed the minimum allowed deltaR (effective plastic strain increment) from 1.0e-16 to 0.0. | ||
+ | |||
+ | 3) In the N-R, there was no check to see if " | ||
+ | < | ||
+ | if(deltaR> | ||
+ | { | ||
+ | deltaR = deltaRMax; | ||
+ | } | ||
+ | </ | ||
+ | I changed this for a better convergence of N-R to: | ||
+ | < | ||
+ | if(deltaR< | ||
+ | { | ||
+ | deltaR = (deltaRMax + deltaRMin) / 2.0; | ||
+ | } | ||
+ | if (deltaR> | ||
+ | { | ||
+ | deltaR = (deltaRMax+deltaRMin)/ | ||
+ | } | ||
+ | </ | ||
+ | |||
+ | With those modifications, | ||
+ | For example the test: | ||
+ | apps.monosMaterials2.EvpIsoDamageLemaitreSouza - PureShear3DKeepSNumEas | ||
+ | |||
+ | Got his number of steps decreased from 81 (abnormaly high) to 26 (normal) on Gaston. | ||
+ | | ||
+ | |||
Line 6: | Line 42: | ||
====Code: | ====Code: | ||
< | < | ||
+ | [m]mtMaterials/ | ||
</ | </ | ||
====Tests: | ====Tests: | ||
< | < | ||
+ | [m]apps/ | ||
</ | </ | ||
- | --- // | + | --- // |
commit/2019/04_05.1554456668.txt.gz · Last modified: 2019/04/05 11:31 by laruelle