Carnegie Mellon University
Mechanical Engineering

Problem 5 : Double Edge Crack in Finite-Width Sheet

Problem Description

# Material : The plate is made of steel with Modulus of elasticity E = 30,000 ksi, and Poisson's ratio = 0.3
# Unit : U.S. Customary Units ONLY. It is important to convert all forces to "lb" and all dimensions to "in".
# Boundary Conditions : The plate has two cracked edge, one is on the right side and the other is on the left side of the plate
# Loading : Uniform tensile Load with magnitude 1000 lb/in^2 acting on the top and bottom of the plate.
# Objectives :

1. To determine stresses in y direction along the line of cracked edge and how much the cracks open up after load is applied to it.
2. To model the plate using diffferent number of mesh elements in the area where stress and displacement are of concern.
# Figure :


1. Specify Geometry

Click on the following in the drop down menu on your right.

PREPROCESSOR -> -Modeling - Create

      CREATE -> -Keypoints

            KEYPOINTS -> In Active CS...

The input box "CREATE KEYPOINTS IN ACTIVE CS" should now appear on the screen. According to the problem description, we have to create a plate with dimensions of 0.5 inch wide and 2.5 inches high. Enter the corresponding x and y coordinates in the box as shown in the figure below. This will create a rectangle of size 2.5 inches x 0.5 inch.

Point 0 -> (0,0,0)
Point 1 -> (0.25, 0, 0)
Point 2 -> (0.5, 0, 0)
Point 3 -> (0.5, 2.5, 0)
Point 4 -> (0, 2.5, 0)

Note: You need not start your index at 0. It can be any number as long as you know the numbering scheme of those keypoints

After finish entering all the values, click OK. Then we need to create line A, B, C, D and E. After we finished creating those lines, then we need to create an area. Steps are as follows.


Then click on keypoint 0, 1 and APPLY. Then repeat the process for 1 and 2. And so on.

You should be able to see 5 lines around the rectangle.

The next step is to create an area inside those 5 lines.

Click OK. Now the blue rectangular plate should appear on your ANSYS GRAPHICS window.