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发表于 2010-12-30 21:01:00
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本帖最后由 ysb1986 于 2010-12-30 21:07 编辑
help里边的 好像都是讲节点是它周围单元的corner值的平均。advanced那个好像要先在同一个坐标系投影,再平均。
Simple averaging means that tensor and vector components are extracted and the invariants are computed prior to averaging. For components, the corresponding components from each element corner are extracted and then they are averaged. For invariants, the corresponding invariants are calculated from each tensor at the element corners and then averaged.
For example, as shown in Nodal Averaging of Elemental Results, there are four tensors, [A2], [B1], [C3], and [D4] at four corners at Node 400.
The average of the xx component at Node 400 is
For the average of an invariant such as von Mises, the von Mises value for all tensor [A2], [B1], [C3] , and [D4] are computed, then they are averaged as follows:
Advanced averaging means that tensor (or vector) results are transformed into a consistent system and then each component is averaged separately to obtain an average tensor (or vector). The invariants are calculated from this averaged tensor. The consistent system can be the global or the user-defined system for solid elements. For shell elements, the consistent system is the nodal projection system, which is the projected global or user-defined system on the nodal projection plane (described in the Projection rule). In the example shown in Nodal Averaging of Elemental Results, the averaged tensor at node 400 is:
Where, are tensors transformed to the reference system for corners A2, B1, C3, and D4, respectively.
The components are extracted and the invariants are computed from this averaged tensor or vector .
The nodal difference is the difference between the maximum and minimum corner results at a node. For tensor/vector components, the corresponding components from each element corner are extracted and the difference is calculated. For invariants, the corresponding invariants are computed from each element corner and then the difference is calculated.
The sign of a value is considered in the difference calculation. For example, the difference for the values, 200, 400, -100, and -500 is 900.
In the example shown in Nodal Averaging of Elemental Results, the nodal difference of tensor component xx at node 400 is:
file:///C:/Altair/hw10.0/help/hv_mv_hg/difference_formula1.png
Where
file:///C:/Altair/hw10.0/help/hv_mv_hg/difference_formula2.png
file:///C:/Altair/hw10.0/help/hv_mv_hg/difference_formula3.png |
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