Error Estimate

[feajob]

Hi,

I am using MSC softwares and I have few questions:

1) I would like to know what is the difference between Error Estimate Direct and Error Estimate Principal?

I got the following results and I would like to interpret them correctly.

Result Elem Stress discont. Volume_1, Error Estimate Direct - Layer (NON-LAYERED)
Entity: Element Tensor

--Entity ID----Scalar Value-
5731718 2.625256
8700383 2.825078

Result Elem Stress discont. Volume_1, Error Estimate Principal - Layer (NON-LAYERED)
Entity: Element Tensor

--Entity ID----Scalar Value-
5731718 2.810257
8700383 3.829084

At the same nodes, I got

--Entity ID----Tresca-
5731718 51.472
8700383 57.864

2) Does it mean that I have about 5 percent error on these nodes?

3) Finally, in order to get more accurate results. Is it better to add the Element Stress Discontinuity to my stresses? or it would be better to add the error on my stresses?

Result Elem Stress discont. Volume_1, Stress Tensor - Layer (NON-LAYERED)
Entity: Element Tensor

--Entity ID-------Tresca----
5731718 4.606151
8700383 8.025431

Please note that, I may get following results:

--Entity ID----Error Estimate Direct
5731718 2.625256 + 51.472 = 54.097
8700383 2.825078 + 57.864 = 60.689

--Entity ID----Error Estimate Principal
5731718 2.810257 + 51.472 = 54.282
8700383 3.829084 + 57.864 = 61.693

--Entity ID----ESD on Tresca----
5731718 4.606151 + 51.472 = 56.078
8700383 8.025431 + 57.864 = 65.889

So, which approach is the best one?

Thank you,
AAY

http://www.geocities.com/fea_tek/asd/