Static structural analysis to find a location for a possible fracture Using different materials in Ansys Workbench.

Aim:- Using different materials, carry out a static structural analysis & Find a location for a possible fracture.

Objectives

-To find out Equivalent stress, Total deformation, and Stress intensity(Learn about what stress intensity is).

-Find a location for possible fracture

Methodology

-Called out the respective system from the Ansys Workbench for the respective Simulation (In our case it's Static Structural)

-Set the material cards for the simulation

-Import the geometry, mesh it, and set appropriate conditions for the simulation.

Procedure:-

-For this assignment, we get two sets of spur gear for structural Analysis. So I had set the Three different material card for three different cases

[NOTE:-  the procedure for setting up the material and card is the same for all three cases, so only one case is explained here]

In Ansys Workbench there is a Static structural system available for static structural Analysis. As you can see in the image.

Engineering data option used to select or set up the Material Cards. The image below is one of the great examples of that

this window will open after clicking on the "Engineering Data" option and as you can see we can set the different material available in the Ansys workbench. For the materials which are not there, we can easily set the new material cards.

The second option is "geometry" from where you can create the New geometry using the "SpaceClaim" option or import the geometry in the "Desing Modeler".

For this assignment, we have geometry so I had used the import option to called out Geometry. The "Model" deck help us to mesh and Define different boundary condition over the geometries.

First, make contact under the connection, here the user should select the possible face that involved in the contact. Apart from that, I had defined the Type Definition- Frictional, Behavior-Symmetric, and changes all other parameters which are a highlight in the above image.

After contact definition it's time to add joints, Here we are using gears so we have to define the axis of rotation. Revolute joint with Body to ground contact is the best one here.

two joints for two gears.

After that its type to deployed mesh over the geometry using mesh menu from the tree.

I had deployed a mesh of element size of 1mm to keep the Nodes limited.

In the "Static-structural" Deck we have to set the boundary condition. I had to given the Rotation moment to the Right gear and the moment to the left one so that it can follow the Right gear rotation movement.

After that, I made an output request for the required results.

The Result evaluation by considering all three materials

1) Cast Iron

Stress intensity:- 350.57 Mpa

Equivalent stress:- 336.35 Mpa

2)Cast steel

Stress intensity:- 360.67 Mpa

Equivalent stress:- 307.73Mpa

3)Cast Bronze

Stress intensity:- 357.67 Mpa

Equivalent stress:- 337.15 Mpa

Equivalence stress means the Average stress on the gear and stress intensity means max stress value, as per the above images we can conclude that the stress area in the gear is near its tooth where the cross-section area is decreases. The stress at the tooth top end is less because it not actually making full contact but the rear part of the tooth that's connected to the ring and having fillet to reduce the stress concentration has exposed to it.

total Deformation is the same which is 30mm for all these three cases, but we talk about Avg strain (deformation) than its different.

-From the observation, we can say that Cast steel is having Max stress value and the strain for that is very low of all. but the Equivalence stress is very less in Cast steel.

-Out of all three materials only the cast steel stress value is less than its Ultimate Tensile Strength. all other materials surpass their UTS value.

Animation Result

Cast Iron

Cast Steel

Cast bronze

Conclusion

-I will recommend the Cast Steel material because the max stress value its experiencing is less than the UTS so its the safe for such kind of load. Also, the strain value is very less for it. means the deformation is very less for such a high-stress value. which is the good nature of the material. We can improve the material property where it's lack by some other means.