http://www.FEA-Forums.com/ FEA Forums » Tag: surface - Recent Posts en Tue, 07 Feb 2012 23:56:58 +0000 http://www.FEA-Forums.com/topic/140#post-164 Thu, 14 Jan 2010 14:45:52 +0000 ajdowdell 164@http://www.FEA-Forums.com/ <p>Wow... I've triple checked to make sure that is says axisymmetric, but I had to click it off, then return to axisymetric and i then corrected the thickenesses back to zero.. Frustrating.. </p> <p>Thanks! </p> http://www.FEA-Forums.com/topic/140#post-163 Thu, 14 Jan 2010 13:53:44 +0000 ajdowdell 163@http://www.FEA-Forums.com/ <p>I've got a sruface model, that has thickness = 0 in Design modeler. Then once I transfer it into simulation (in 2D mode accepting 0 thickness models only) some of the surface models gain a thickness specification that is assigned as 1. You cannot go in to the thickness field in the details box and set thickness to 0 because then it puts a ? infront of the object,and won't solve at all. Sometimes all objects are assign a thickness of 1, sometimes one object remains a true "thin" surface.</p> <p>In my little world since it's set on axisymetric, there should be NO option for a thickness. Assigning a thickness to an axisymetric thin model is not even really comprehensible... </p> <p>This if from the help menu:</p> <p>Importing Surface Body Thickness<br /> Surface body thickness will be imported from CAD (including DesignModeler) if, and only if, the existing surface body thickness value in Simulation is set to 0 (zero). This is true on initial attach and if you set the surface body thickness value to zero prior to an update. This allows you the flexibility of updating surface body thickness values from CAD or not.</p> <p>That to me means that the model must be correct coming out of DM into sim, and that the thickness has to be added in the simulation somewhere. </p> <p>Does any one know where the setting might be to change this or have any ideas? Thanks! </p> http://www.FEA-Forums.com/topic/129#post-151 Thu, 03 Dec 2009 13:06:37 +0000 pday 151@http://www.FEA-Forums.com/ <p>I am fairly new to ANSYS and have been trying to model the interaction between glass micro-spheres and silicone polymer micro-structures for my dissertation research. I've been working through the online manual, but have been getting very odd results when running the simulation. Any help at all would be appreciated. The summary of my problem is as follows:</p> <p> Modelling:</p> <p>It may help to first refernce the first two images at : <a href="http://bdml.stanford.edu/twiki/bin/view/Main/AnsysModelling" rel="nofollow">http://bdml.stanford.edu/twiki/bin/view/Main/AnsysModelling</a></p> <p>I have a single, thin wedge shape modelled with SOLID95 elements. The body of the wedge (everything but the round tip) is comprised of 20-node bricks. The rounded top of the wedge is modelled with 10-node tetrahedron, with pyramidal interface eelements between the tets and the bricks. The material model for the wedge is a linear isotropic one with ballpark values of: E=1e6 and PR=0.49. I also gave it a friction coefficient of 1.</p> <p> Contact Elements: </p> <p>The contact surface is showin the third picture in the above link. </p> <p>I set the type to CONTA174 and, using the meshing tool, meshed the shown areas with triangular elements on the round top of the wedge, and quad elements on the front face. I then set the R1 value in the real constant set to the desired radius of my sphere, which is the rigid target. Using the same real constant set, I set the type to TARGE170 and created a pilot node element where I wanted the center of the sphere and then created a sphere element on top of the pilot node. The sphere was the appropriate size, so I believe the shared real constant set is correctly set up. </p> <p> Simulation:</p> <p>I constrained the bottom of the wedge in all DOF, and put a simple displacement load on to the pilot node of the sphere. I want the sphere to move straight down a certain distance, and observe how the wedge deforms. I didn't change much in the way of thesolution controls. I set it up as a large displacement static problem with a 250 set as the number of substeps and 150 as the minimum number of substeps. The simulation fails each time, however, due to an error in element formulation. It's easy to see why there is an error when I plot the deformed shape of the last solution set. The elements become highly distorted almost as soon as the target comes in to contact with the contact surface. This can be seen in the last image in the link above. </p> <p>As I said before, I'm a bit new to contact simulation in ANSYS. Maybe I've made a silly, rookie error. Any guidance at all would be greatly appreciated. </p> <p>Paul </p>