

March 27, 2020 at 6:59 pmjfm418Subscriber
Hello,
I am trying to reproduce compression, tension, and shear on a 2D element/surface (see picture below) by applying normal or tangential force but I am not sure where I should be placing the fixed support. If I do not put any support I get pivot errors because the system is underconstrained. I would really appreciate any tip on this.
Thanks a lot.
Jad

March 27, 2020 at 9:36 pmpeteroznewmanSubscriber
Jad,
The diagrams and matrices refer to y and z, but in ANSYS, 2D is in X and Y directions.
Are you trying to solve 2D problems assuming Plane Stress or Plane Strain?
For applying tension or compression forces along the X axis, assume Quarter Symmetry. That means consider the lower left corner of the square to be the center of a square twice as large. Apply a Displacement of X = 0, Y = Free to the left edge. Apply an X component of force to the right edge. Apply a Displacement of X = Free, Y = 0 to the bottom edge. This will work for a single element or a mesh of many elements, however it is not useful for shear strain since that is not a symmetric load.
Note that applying forces to an element will not result in the strain matrix you show. You are showing a strain matrix where the strain in the Y direction is zero. That is an unusual constraint. If there are no forces acting in the Y direction, but only in the X direction, there will be a strain in the X direction of Stress/E but the strain in the Y direction will occur due to the Poisson's Ratio.
If you want zero strain in the Y direction as shown in your matrix, then you need to apply Y=0 Displacement constraint to the top edge. If you want to apply strain in the X direction instead of force, you do that by using a Displacement on the right edge that is nonzero in X and leave Y free. For a strain of 0.01 use a Displacement that is 1% of the X dimension of the surface.
We can discuss Shear Strain in a later post.

March 29, 2020 at 8:44 amjfm418Subscriber
Actually you are right. I am trying to assume plane strain which makes everything a lot easier.
For tension and compression, I simply set displacements of Y=0 on the top and bottom ledge and opposite nonzero displacements in the X direction on the right and left edges with Y = 0.
For shear, I only applied opposite nonzero displacements on the top and bottom edges with Y=0.
For the last example (twisting), I tried to combine the displacements I applied for tension and shear but I get an error due to conflicting DOF constraints at one or more nodes. Not sure how else to simulate it. Would like to hear your thoughts on this.
Below are images of the deformation for:
Tension
Compression
Shear

 You must be logged in to reply to this topic.
Simulation World 2022
Check out more than 70 different sessions now available on demand. Get inspired as you hear from visionary companies, leading researchers and educators from around the globe on a variety of topics from lifesaving improvements in healthcare, to bold new realities of space travel. Take a leap of certainty and check out a session today here.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Ansys Blog
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
 How to calculate the residual stress on a coating by Vickers indentation?
 An Unknown error occurred during solution. Check the Solver Output…..
 Saving & sharing of Working project files in .wbpz format
 Solver Pivot Warning in Beam Element Model
 Understanding Force Convergence Solution Output
 whether have the difference between using contact and target bodies
 Colors and Mesh Display
 The solver engine was unable to converge on a solution for the nonlinear problem as constrained.
 Massive amount of memory (RAM) required for solve
 What is the difference between bonded contact region and fixed joint

1960

1720

931

698

389
© 2022 Copyright ANSYS, Inc. All rights reserved.