Subject: Re: Sanity check Author: Kim Ravn-Jensen Date: 2001-05-14 03:33:00I agree with Jason: Implementing such a sanity check would seem like a drop in the ocean in comparison with the potential insanity of all imaginable ANSYS inputs added together.
But the implementation of the "new" ANSYS contact elements would benefit from the addition of postprocessing features that I have had to do through macros:
1. Contour plots of the "utilized mu": the length of the shear traction vector divided by the normal pressure. This will enable you to check your sanity after the analysis, which is much better than never at all. I have also seen design criteria based on this quantity.
2. Contour plots of the sliding (vector length) during the last load step. Many analyses consist of a settling step with large sliding values followed by load steps with smaller sliding values which you want to study for themselves.
--- In xansys@y..., Jason Husband wrote: > Some alloys of aluminium (against each other) can easily exceed mu=1.
> I would rather see ANSYS,ink spend their time improving parts of the > code that work poorly. > Jason Husband
> Mark Rodamaker wrote:
> > I think it would be reasonable for Ansys to output a warning however mu can > > exceed 1.0 but not by much for normal materials like rubber on concrete. Car > > racing tires can have mu slightly over 1.0 but tire wear is greatly > > exaggerated compared to normal road tires. Lateral acceleration of at least > > 2.5 g's is possible in cars with aerodynamic down force but mu is still > > around 1.0.
> > ----- Original Message ----- > > From: "Gardner, Kevin" > > To: > > Sent: Friday, May 11, 2001 12:24 PM > > Subject: RE: [xansys] Sanity check
> >> Dan,
> >> What if one were modeling velcro. I think it would have a mu >>1. I
> > guess
> >> it's pretty easy to argue that velcro would hardly be considered a
> > friction
> >> problem... but you never know how Ansys users are going to try and use the > >> code.
> >> Kevin Gardner > >> Engineering Mechanics > >> Honeywell Engines & Systems
> >> -----Original Message----- > >> From: Dan Bohlen [mailto:dan.bohlen@a...] > >> Sent: Friday, May 11, 2001 12:18 PM > >> To: xansys@y... > >> Subject: [xansys] Sanity check
> >> Dear Ansys Inc,
> >> A fellow engineer here ( really it wasn't me!) basically made a typo and > >> input a LARGE value for the coefficient of friction as a material > >> property. By experience I know I get warnings when I set densities to > >> zero. Would it be reasonable to have Ansys issue a warning when a mu>1 > >> is input. I'm not 100% sure if, theoretically, you can have a value > >> greater than one. But even if, in theory, you can - it's probably a > >> rare enough input that the few rare false alarms would be worth the few > >> sanity checks that might save some folks days of model de- bugging.
> >> Dan Bohlen Phone: (513) 243-4645 / Dial Comm [8*332- 4645] > >> Stress Analyst Email: dan.bohlen@a... M/D K-105 > >> GE Aircraft Engines Fax: (513) 243-4888 or 243-4886
> >> Whenever you find that you are on the side of the majority, it is time > >> to reform. - Mark Twain