{"id":25647,"date":"2011-05-25T16:57:00","date_gmt":"2011-05-25T16:57:00","guid":{"rendered":"https:\/\/www.padtinc.com\/2011\/05\/25\/a-further-assessment-of-design-assessment\/"},"modified":"2022-03-29T19:06:24","modified_gmt":"2022-03-29T19:06:24","slug":"a-further-assessment-of-design-assessment","status":"publish","type":"post","link":"https:\/\/www.padtinc.com\/2011\/05\/25\/a-further-assessment-of-design-assessment\/","title":{"rendered":"A Further Assessment of Design Assessment"},"content":{"rendered":"\n

Last week’s PADT ANSYS Webinar Series webinar was on a little-used feature in ANSYS Mechanical called Design Assessment, or DA.\u00a0 If you missed it, here is a PDF of the PowerPoint:<\/p>\n\n\n\n

<\/object>2011_05_19_Design_Assessment<\/a>Download<\/a><\/div>\n\n\n\n

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As promised, this week’s The Focus posting will be a follow-up on that webinar with an in-depth look at the scripts that were used in the example.  But first, let us review what DA is for those that don\u2019t remember, fell asleep, or don\u2019t want to sit through 60+ minutes of me mumbling into the telephone.<\/p>\n\n\n\n

Review of DA<\/h2>\n\n\n\n

Design Assessment is a tool in ANSYS Workbench that works with ANSYS Mechanical to take results from multiple time or load steps, perform post processing on those results, and bring the calculated values back into ANSYS Mechanical for viewing as contour plots.  It was developed to allow the ANSYS, Inc. developers to add some special post processing tools needed in the off shore industry, but as they were working on it they saw the value of exposing the Application Programmers Interface (API) to the user community so anyone can write their own post processing tools.<\/p>\n\n\n\n

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You use it by adding a Design Assessment system to you project.  In its most basic form, the default configuration, it is set up to do load case combinations.  That in itself is worth knowing how to use it.  But if you want to do more, you can point it to a custom post processing set of files and do your own calculations.<\/p>\n\n\n\n

A custom DA is defined by two things.  First is an XML file that tells ANSYS Mechanical what user input you want to capture, how you want to get results out of mechanical, what you want to do with the results, and how you want them displayed in your model tree.  Second is one or more Python scripts that actually do the work of capturing what the user input, getting results, doing the calculation, and sticking the resulting values back in the model.  Both are well documented and, once you get your head around the whole thing, pretty simple.<\/p>\n\n\n\n

Right now DA works with Static and Transient Structural models.  It also only allows access to element stress values.  Lots of good enhancements are coming in R14, but R13 is mature enough to use now.<\/p>\n\n\n\n

If that review was too quick, review the recording or the PowerPoint presentation.<\/p>\n\n\n\n

A Deep Dive Into an Example<\/h2>\n\n\n\n

For the webinar we had a pretty simple, and a bit silly, example \u2013 the custom post processing tool took the results from a static stress model and truncates the stress values if they are above or below a user specified value.  Not a lot of calculating but a good example of how the tool works. <\/p>\n\n\n\n

Note, this posting is going to be long because there is a lot of code pasted in.  For each section of code I\u2019ll also include a link to the original file so you can download that yourself to use.<\/p>\n\n\n\n

Here is the XML file for the example:<\/p>\n\n\n\n

  <?xml version=\"1.0\" encoding=\"utf-8\"?>\n  <!-- \n  www.PADTINC.com \n            XML file for ANSYS DA R13\n            Demonstration of how to use DA at R13\n            Goes through results and sets stresses below floor value to floor\n              value and above ceiling value to ceiling value.     \n              \n          User adds DA Result to specify Floor and Ceiling\n          Attribute group can be used to specify a comment\n          \n          Calls da_trunc_solve.py and da_trunc_eval.py in c\n          \n          Eric Miller\n          5\/18\/2011\n  -->\n   \n  <DARoot ObjId =\"1\" Type=\"CAERep\" Ver=\"2\">\n    <Attributes ObjId=\"2\" Type=\"CAERepBase\" Ver=\"2\">\n      <DAAttribute ObjId=\"101\" Type=\"DAAttribute\" Ver=\"2\">\n        <AttributeName PropType=\"string\">Stress Value<\/AttributeName>\n        <AttributeType PropType=\"string\">DropDown<\/AttributeType>\n        <Application PropType=\"string\">All<\/Application>\n        <Validation PropType=\"vector&amp;lt;string>\">\n               SX,SY,SZ,SXY,SYZ,SXZ,S1,S2,S3,SEQV\n        <\/Validation>\n      <\/DAAttribute>\n      <DAAttribute ObjId=\"102\" Type=\"DAAttribute\" Ver=\"2\">\n        <AttributeName PropType=\"string\">Stress Floor<\/AttributeName>\n        <AttributeType PropType=\"string\">Double<\/AttributeType>\n        <Application PropType=\"string\">All<\/Application>\n        <Validation PropType=\"vector&amp;lt;string>\">-1000000,10000000<\/Validation>\n      <\/DAAttribute>\n       <DAAttribute ObjId=\"103\" Type=\"DAAttribute\" Ver=\"2\">\n        <AttributeName PropType=\"string\">Stress Ceiling<\/AttributeName>\n        <AttributeType PropType=\"string\">Double<\/AttributeType>\n        <Application PropType=\"string\">All<\/Application>\n        <Validation PropType=\"vector&amp;lt;string>\">-1000000,10000000<\/Validation>\n      <\/DAAttribute>\n      <DAAttribute ObjId=\"201\" Type=\"DAAttribute\" Ver=\"2\">\n        <AttributeName PropType=\"string\">User Comments<\/AttributeName>\n        <AttributeType PropType=\"string\">Text<\/AttributeType>\n        <Application PropType=\"string\">All<\/Application>\n      <\/DAAttribute>\n    <\/Attributes>\n    <AttributeGroups ObjId =\"3\" Type=\"CAERepBase\" Ver=\"2\">\n      <DAAttributeGroup ObjId=\"100002\" Type=\"DAAttributeGroup\" Ver=\"2\">\n        <GroupType PropType=\"string\">User Comments<\/GroupType>\n        <GroupSubtype PropType=\"string\">Failure Criteria<\/GroupSubtype>\n        <AttributeIDs PropType=\"vector&amp;lt;unsigned int>\">201<\/AttributeIDs>\n      <\/DAAttributeGroup>\n    <\/AttributeGroups>\n    <DAScripts ObjId=\"4\" Type=\"DAScripts\" Ver=\"2\">\n      <Solve PropType=\"string\">c\n      <Evaluate PropType=\"string\">c\n      <DAData PropType=\"int\">1<\/DAData>\n      <CombResults PropType=\"int\">1<\/CombResults>\n      <SelectionExtra PropType=\"vector&amp;lt;string>\">DeltaMin, DeltaMax<\/SelectionExtra>\n    <\/DAScripts>\n    <Results ObjId=\"5\" Type=\"CAERepBase\" Ver=\"2\">\n      <DAResult ObjId =\"110000\"  Type=\"DAResult\" Ver=\"2\">\n        <GroupType PropType=\"string\">Ceiling and Floor Values<\/GroupType>\n        <AttributeIDs PropType=\"vector&amp;lt;unsigned int>\">101,102,103<\/AttributeIDs>\n        <DisplayType PropType=\"string\">ElemCont<\/DisplayType>\n      <\/DAResult>\n    <\/Results>\n  <\/DARoot>\n<\/code><\/pre>\n\n\n\n