Week 2 Bevel Gear Challenge

Understanding the effect of static structural analysis on a Bevel Gear

Objective: To study and perform grid dependency test on bevel gear with base mesh size of 6, 5 and 4 mm

Grid independent:- it a very important issue in numerical simulations grid-independent means calculation result change so little along with a denser or loser grid that the truncations error can be ignored in numerical simulations

Basically a mesh convergence test should mean computing the solutions on successively finer grids. The difference two refinements are usually taken as a measure of the accuracy of the accuracy of the course of the two. Usually a calculations should approach the correct answer as they become finer, hence the term grid converge.

Measurement of value of total Deformation, Equivalent stress and Equivalent Elastic strain

Case1- mesh size 4

Case2- mesh size 5

Case3-mesh size 6

Simulation Process:

Input Geometry

The given module was inserted into the mechanical GUI. Since the Centre portions of the driven and the driving and the driving gear were not necessary, they were edited in the Space Claim GUI. The Geometry has shown below

Material:

The material used for the entire simulations was structural steel

Mesh

• The mesh was assigned to the given module. At first a default mesh was used. It was found that the default mesh was too coarse for the simulations to run successfully. Hence a face sizing was inserted where each of the faces of the both the gears included were selected and the element size was specified to 1.75mm respectively .the details of the default mesh and the face sizing used are mentioned

Contacts:

• Following the assignment of material, the connections in the bevel gear was specified. The small Gear was the contact body and the Big Gear was kept as the target body. The face of the respective gear were selected and specified. the connections and their details have been mentioned

Joints:

• The joints in the gears were also specified. The details of the these joints are mentioned below
• For the revolute joints it was made sure that both of them rotated about the Z-axis direction. The small gear in the clockwise directional and the big gear in the anti-clockwise direction

Analysis setting:

• The analysis is setup for 6 steps. This does not control the time step, but is only an indication of points where boundary changes. The time step is auto controlled by specifying initial ,min and max time step

Boundary conditions

• A joint rotations is given to one revolute joint in increments of 20deg for 6 steps
• This joint rotate against a moment load (100N-mm) in the other revolute joint

Solutions:

All the necessary output variable are selected such as von Mesis stress, stress intensity, equivalent strain etc.

Note- for all three cases the set are same as above we discuss

Result –

Case- 1 simulation was conducted for the mesh having an element size of 4mm

equivalent stress

equivalent strain

deformation

Case- 2 simulation was conducted for the mesh having an element size of 5mm

equivalent stress

equivalent strain

deformation

Case- 3 simulation was conducted for the mesh having an element size of 6mm

equivalent stress

equivalent strain

deformation

On comparing the value, we can see that the value keep on increasing with decrease in element size which is more accurate. This continues unite the most accurate value is obtained as can observe in the total deformation value. This prove our grid dependency test

Conclusion:

• Life decreases as can be observed from the report as load increased
• More chances of failure in case of increased load as safety factor in case of increased load was observed was observed to be 0.624
• Max stress included was more for increased load case
• Max deformation was observed to be same for both