Week 8 Worm Gear Challenge

Objective:

To perform transient structural analyis on a worm gear assembly. Since we are using an academic version the model is cut in half and it must be taken to the edges. In order to obtain Equivalent stress, Equivalent Strain and Total deformation while refining the mesh also.

Setup:

Since no materials are added we import the geometry and open it in space claim. Once opened in spaceclaim draw a line in the center pull down and then select the option cut. After selecting the option cut through the half and we have the model for academic version. After that close spaceclaim and open the model in the mechanical module. Once opened rename the parts as worm and gear. As for the contacts we add some more faces of the gear on both side of the worm to the contact. After that a mesh size of 2mm for the worm. We give two revolute joint both body to ground, the first one we select the inside of the worm and for the second joint we select the semi circle surface of the inner side of gear. Change smoothing to low and element order to linear. Moving onto analysis settings we give 15 steps selecting all 15 steps switch auto time stepping to On. After that give initial time step as 0.2, minimum time step 0.2 and maximum time step as 0.5. Change weak springs to program controlled and switch on large deflection. Under output controls change every control to yes except Contact Miscellaneous which stays No. After that we can give a joint load for the ground to worm joint. We give rotational values which are 150,300,450 so on until 2250( each with a 150 gradient). After that we add the required solution like Equivalent stress, Equivalent Strain and total deformation.

Equivalent Stress:

The maximum stress was developed at one of the tooth surface in contact with the worm which was at 286.77 Mpa.

Equivalent Elastic Strain:

The maximum strain also coincides with maximum stress which is at a value of 0.0015782 mm/mm.

Total Deformation:

The total deformation of the worm gear model is shwon, unsurprisingly the most deformation occured at the teeth surface of the gear which was at 21.23 mm.

Conclusion:

The maximum stress (286.77 Mpa) and maximum strain (0.0015782mm/mm) coincided at the same point which is on the gear at the contact between worm and gear. As expected the maximum deformation also occured on the teeth of the gear at 21.23mm.While there was slight deformation of about 11 to 13 mm on the tooth of the worm. Also the maximum amount of stress developed in the worm was 119.66 Mpa, and maximum strain was 0.00081033 mm/mm occuring at the same point.