TRANSIENT ANALYSIS OF WORM GEAR ASSEMBLY

Challenge: Transient Analysis of Worm Gear Assembly

Objective: Rotate the worm so as to get to almost the end of the half-cut GEAR and get results for Equivalent stress, Equivalent elastic strain and the total deformation in the model.

Since I’m performing the analysis on ANSYS academic version, the gear is cut into half. This is done by using the SPLIT BODY tool in ANSYS SpaceClaim. The tool helps to select a plane along which the body needs to be split and then allows us to remove the unwanted portion. The split gear assembly looks as follows:

The analysis is performed with Structural Steel as the material for the assembly.

Contacts:

Once ANSYS Mechanical APDL is loaded, the first important step is to properly define the contacts. The default contact pair generated by the solver is further detailed by defining all the faces on the gear which will come in contact with the worm. Here, the Worm is the CONTACT body and the Gear is the TARGET body. Frictionless contact is defined for the pair and the rest of the parameters are kept as default.

Joints:

Since the gears are supposed to rotate along their own axes, BODY TO GROUND REVOLUTE joints are defined for both gear and worm.

Mesh:

I’ve performed the analysis with default solver generated mesh with ADAPTIVE SIZING. The generated mesh has 10239 Nodes and 5001 Elements. Most of the elements fall in the higher quality range as seen from the element quality graph.

Analysis Settings:

The analysis is performed in time steps. Keeping the load to be applied and the distance to be covered in mind, I’ve chosen 40 steps for analysis. The initial, minimum and maximum time steps are defined along with other parameters as shown below:

Joint Loads:

Rotation is applied to the WORM in incremental steps as defined in the analysis settings. Through trial and error, I arrived at an optimum value of 40-degree rotation per step. For 40 steps, the total rotation adds to 1600 degrees.

When defining the Rotational load, the axis of rotation is adjusted so that the worm rotates in ANTI CLOCKWISE direction, as per defined contact with the gear.

Solution:

The parameters to be evaluated are Equivalent stress, Total Deformation and Elastic Strain.

The results obtained are as follows:

Equivalent Stress (Von-Mises)= 1439.5 MPa (Max)

Total Deformation= 15.32 mm (Max)

Equivalent Elastic strain= 8.172E-3 mm/mm (Max)

SIMULATION:

Equivalent Stress (Von-Mises)= https://youtu.be/nGFBuU2sgNA

Total Deformation=https://youtu.be/YCfL61tr2UA

Equivalent Elastic STRAIN= https://youtu.be/dH3nsFZ7eOk