clarification of Analusis in Mechanica

[ptc-1428410]

1. can i control mesh size in mechanica?(is there any effect of aspect ratio on mesh),according to my knowledge, even if i control aspect ratio ,i am getting same results. 2.can i get reaction forces at constrained points? 3.i want to know about shell reaction force,(physical significance in software) In results window this option was given. if i give point constraints ,it is giving concentrated stress in results , is it correct?how it can be overcome. i hope best from u guys,

[AndyDeighton-di]

Venu, 1) Changing aspect ratio will effect the mesh size, however what you are looking for is a Wildfire 4.0 enhancement: http://www.ptc.com/appserver/wcms/relnotes/note.jsp?&im_dbkey=50957&icg_dbkey=826 2) Yes: After completing an analysis define a results window. Set Display Type to #Model and Quantity to #Reactions at Point Constraints. Constrained points will be labeled with corresponding reaction values. 3) This should help: http://www.ptc.com/cs/cs_25/howto/mst730/mst730.htm 4) Point constraints do give concentrated stress (singularity). Stress=Force/Area so if your area is zero (point constraint) Stress is very high (divide by zero). Try to constrain something with area to overcome this. There is a Wildfire 4.0 enhancement which will help: http://www.ptc.com/appserver/wcms/relnotes/note.jsp?&im_dbkey=50964&icg_dbkey=826 I hope this helps. Best Regards Andy

[ptc-1428410]

Thank u Mr.Andrew there is little confusion in second question I considered model constraints for small area to avoid concentrated stress. generally we get stresses in results here i want reaction forces Regards Venu

[AndyDeighton-di]

Venu, You don't need to call me Mr. Andrew, Andy is just fine ! Your question asked for reaction forces at points, if it is an area you are constraining, then this should help: http://www.ptc.com/cs/cs_25/howto/mst903/mst903.htm If you cannot access this document, email me and I'll send it to you. Best Regards Andy

[ptc-1428410]

Hi Andy, We have small queries regarding constraints we were constraining the model in 2 ways, we want to know which one is correct. the task is to constrain a plate at 4 locations (corners) and a 40kg load was applied uniformly all over the surface. we want to know the reaction forces at all the 4 constrained locations we created 4 regions to apply constraints to the model. first we constrained all the 4 zones in one constraint and run the analysis. the reaction what we got was 40kg secondly we contrained all the 4 zones in four different constraints in one set and run the analysis. we got 4 different reactions as below 177 , 177, 113, 114. i think it should be equalant to the applied external load. and also stresses are different in both the cases. Please tell us which one we have to follow and why?

[AndyDeighton-di]

Venu, What Release and datecode of Pro/ENGINEER are you running - there was an issue prior to Wildfire 4.0 M070 with reaction measures, although I doubt this would give such an error. I'll send you a Wildfire 3.0 M080 model with constraints and reaction measures similar to the one you describe, which works fine. Best Regards Andy

[ptc-1428410]

We r using Wildfire 3.0 M010