p1: Advanced X-Sectional Results: Using Paths to Post Process Results using ansys

Introduction

This tutorial was created using ANSYS 7.0 The purpose of this tutorial is to create and use 'paths' to provide extra detail during post processing. For example, one may want to determine the effects of stress concentrators along a certain path. Rather than plotting the entire contour plot, a plot of the stress along that path can be made.

In this tutorial, a steel plate measuring 100 mm X 200 mm X 10 mm will be used. Three holes are drilled through the vertical centerline of the plate. The plate is constrained in the y-direction at the bottom and a uniform, distributed load is pulling on the top of the plate.

Preprocessing: Defining the Problem

Give the example a Title
- Utility Menu > File > Change Title ...
  /title, Use of Paths for Post Processing
Open preprocessor menu
- ANSYS Main Menu > Preprocessor
  /PREP7
Define Rectangular Ares
- Preprocessor > Modeling > Create > Areas > Rectangle > By 2 Corners
  BLC4,0,0,200,100
- Create a rectangle where the bottom left corner has the coordinates 0,0 and the width and height are 200 and 100 respectively.
Create Circles
- Preprocessor > Modeling > Create > Areas > Circle > Solid Circle
  cyl4,WP X,WP Y,Radius
- Create three circles with parameters shown below.
  Circle Parameters
  WP X WP Y Radius
  1 50 50 10
  2 100 50 10
  3 150 50 10
Subtract the Circles
- Preprocessor > Modeling > Operate > Booleans > Subtract > Areas
- First, select the area to remain (ie. the rectangle) and click OK. Then, select the areas to be subtracted (ie. the circles) and click OK.
- The remaining area should look as shown below.
Define the Type of Element

Circle	Parameters
WP X	WP Y	Radius
1	50	50	10
2	100	50	10
3	150	50	10

Preprocessor > Element Type > Add/Edit/Delete...
For this problem we will use the PLANE2 (Solid Triangle 6node) element. This element has 2 degrees of freedom (translation along the X and Y axes).
In the 'Element Types' window, click 'Options...' and set 'Element behavior' to Plane strs w/thk

Define Real Constants

Preprocessor > Real Constants... > Add...
In the 'Real Constants for PLANE2' window, enter a thickness of 10.

Define Element Material Properties
- Preprocessor > Material Props > Material Models > Structural > Linear > Elastic > Isotropic
- In the window that appears, enter the following geometric properties for steel:
  1. Young's modulus EX: 200000
  2. Poisson's Ratio PRXY: 0.3
Define Mesh Size
- Preprocessor > Meshing > Size Cntrls > ManualSize > Areas > All Areas...
- For this example we will use an element edge length of 5mm.
Mesh the Area
- Preprocessor > Meshing > Mesh > Areas > Free > click 'Pick All'

Solution Phase: Assigning Loads and Solving

Define Analysis Type

Solution > Analysis Type > New Analysis > Static
ANTYPE,0

Apply Constraints

Solution > Define Loads > Apply > Structural > Displacement > On Lines
Constrain the bottom of the area in the UY direction.

Apply Loads

Solution > Define Loads > Apply > Structural > Pressure > On Lines
Apply a constant, uniform pressure of -200 on the top of the area.

Solve the System

Solution > Solve > Current LS
SOLVE

Postprocessing: Viewing the Results

To see the stress distribution on the plate, you could create a normal contour plot, which would have the distribution over the entire plate. However, if the stress near the holes are of interest, you could create a path through the center of the plate and plot the stress on that path. Both cases will be plotted below on a split screen.

Contour Plot

Utility Menu > PlotCtrls > Window Controls > Window Layout
Fill in the 'Window Layout' as seen below
General Postproc > Plot Results > Contour Plot > Nodal Solu > Stress > von MisesThe display should now look like this.

To ensure the top plot is not erased when the second plot is created, you must make a couple of changes.
Utility Menu > PlotCtrls > Window Controls > Window On or Off. Turn window 1 'off'.
To keep window 1 visible during replots, select Utility Menu > PlotCtrls > Erase Option > Erase Between Plots and ensure there is no check-mark, meaning this function off.
To have the next graph plot in the bottom half of the screen, select Utility Menu > PlotCtrls > Window Controls > Window Layout and select 'Window 2 > Bottom Half > Do not replot'.

Create Path

General PostProc > Path Operations > Define Path > By Location
In the window, shown below, name the path Cutline and set the 'Number of divisions' to 1000
Fill the next two window in with the following parameters
Parameters
Path Point Number X Loc Y Loc Z Loc
1 0 50 0
2 200 50 0

When the third window pops up, click 'Cancle' because we only enabled two points on the path in the previous step.

Map the Stress onto the Path

Parameters
Path Point Number	X Loc	Y Loc	Z Loc
1	0	50	0
2	200	50	0

General Postproc > Path Operations > Map onto Path
Fill the next window in as shown below [Stress > von Mises] and click OK.
The warning shown below will probably pop up. This is just saying that some of the 1000 points you defined earlier are not on interpolation points (special points on the elements) therefore there is no data to map. This is of little concern though, since there are plenty of points that do lie on interpolation points to produce the necessary plot, so disregard the warning.