How to trust Stress Plots

Rahul_P1

Hey there,

short question which came to my mind on thinking about my FEM class:

I need to check for some stress discontinuity. It means how great is the change from one element to the next where the stress value is interpolated.

In this term there is a rule of thumb, that the stress discontinuity should not be greater than 10% of the whole stress range, so that

(Stress(node1) - Stress(node2)) / Max Stress - Min Stress < 10%

Is there a way to plot those discontinuity also in hyperview? Any other options to check that you can trust the stress values?

Thanks in advance.

Manuel

Rahul_P1

As the HyperWorks Student guide - ebook says, you should start with a visual check for Discontinuous or an abrupt change in the stress pattern across the elements, there should not be a clear change in contour colour across elements. 

If corner data is available, the Use corner data option can be enabled. If you activate the option, HyperView displays color bands by interpolating available corner results within each element. A discontinuity of the result distribution across element boundaries can be seen.

Then you can use variation as suggested here

To plot discontinuity in HyperView, activate the Variation check box below the Averaging method in contour panel.

Variation percentage at a node = (Difference at that node/Difference in all nodes from the selected components) x 100

This will calculate the averaging results for some nodes, depending on the variation (%) given. If the variation is turned off, the averaging results are plotted for all nodes.

 

, If the variation in the results is smaller than the specified percentage, HyperView will average the corner results to the nodes. If the variation is larger than the specified percentage, HyperView will keep the discontinuity of the results.

Also change reader options to by 1 component or property as necessary to avoid discontinuity due to lack of averaging in component boundaries, the nodes on the boundary of two components will have two results and this needs to be avoided.

Read HyperWorks Desktop Applications > HyperView > Results > Variation Percentage Control

and HyperWorks Desktop Applications > HyperView > HyperView Solver Interfacing > Interfacing with Abaqus > Result Data from ODB > Contour Panel for Abaqus Results

and HyperWorks Desktop > HyperView > Result Data Analysis > HV-3060: Transforming and Averaging Stresses