Week 8 Worm Gear Challenge

OBJECTIVE: To perform transient structural analysis on a worm gear mechanism rotate the worm so as to get to almost the end of the half-cut and get the required result in ANSYS.

PROCEDURE:

• Open Ansys Workbench and choose transient structural.
• In the Engineering data, let the material be structural steel.

• For the geometry, right-click and import the given "worm_gear.x_t" and open with space claim.

• In space claim to cut the gear into half first draw a rectangle on the surface of the gear such that it covers the half portion of the gear then use the Cut option present under Edit -> Pull and drag the rectangle to remove the gear surface.

• Now in the workbench goto Model -> Edit, in the model window check the Geometry for the material and assign Structural Steel to both components.

• In contact, the contact bodies are of worm and target bodies are of gear so choose additional surface in the direction it will rotate for target bodies, and the Contact type will be fricitionless.

• Provide body to ground joint, type= Revolute to bother the gear and worm and check the orientation of the direction of rotation.

• For mesh, element size= 2.5 mm, Use adaptive sizing= Yes and click on generate mesh.

• For analysis, the total number of steps will be 15 and for the 1st step Initial Time Step= 0.2 s, Minimum Time Step= 0.2 s, Maximum Time Step= 0.5 s, Weak spring= program-controlled, large deflection= On and switch Output controls to yes.

For times step 2 to 15 select all the time step switch carry over time step= on and Minimum Time Step= 0.2 s and Maximum Time Step= 0.5 s.

• To provide joint load, click on transient -> joint, Joint= Revolute Ground to Worm, Type= Rotation, Magnitude= Tabular Data and provide the degree of rotation in the tabular data.

• In the solution request select for the required output like Total deformation, Equivalent Elastic Strain and Equivalent Stress. Click on solve to generate the result.

RESULT:

TOTAL DEFORMATION

EQUIVALENT ELASTIC STRAIN

EQUIVALENT STRESS

	Total Deformation (mm)			Equivalent Elastic Strain (mm/mm)			Equivalent Stress (MPa)
Material	Min.	Max.	Average	Min.	Max.	Average	Min.	Max.	Average
Structural Steel	1.3664	13.45	7.681	5.5198e-012	8.1852e-003	3.3604e-004	9.3956e-007	1608.6	52.231

CONCLUSION:

So from the simulation, it can be inferred that for structural steel the maximum total deformation, maximum equivalent elastic strain and maximum equivalent stress are experienced by the gear only while the gear was rotated near to the end of the half cut.

Simulation File: "https://drive.google.com/file/d/1eVDc0XkAEWVuFshYEEqhjJC2RsVmMQNh/view?usp=sharing"