Week 1 Spur Gear Challenge

Understanding the effect of static structural analysis on a Spur Gear

Objective: To study the static structural analysis on a spur Gear with three different material and finding out Equivalent stress, total deformation and stress intensity

Procedure

the Spur gear model need to analysed with three material , since the same model and material library including all three material can be common for the three case , single project can be created as below

• Open ansys workbench
• Update the material module as cast iron , cast steel cast bronze for each of three model choose the corresponding material
• Then update the mode and edit it

Mesh

• In the mechanical tab update the mesh. the mesh size is given of 1 mm,

Contacts:

• A frictional contact is to be setup between the two spur gears. only the necessary faces that come into contact are selected for Contact Bodies and target Bodies respectively .Modify the Formulations and interface treatment as appropriate

Joints:

Revolute joints are setup for the two gears with respect to the ground. These joints are needed to apply boundary conditions to the gears.

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 30deg for 6 steps
• This joint rotate against a moment load (10000NM) in the other revolute joint

Solutions:

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

Observations -

cas1- cast iron

stress result-

strain resut-

displacement -

case2- cast stell

equivalent stress-

strain

Displacement-

case3- cast bronze

equivalent stress-

strain

displacment -

RESULT
Case1- cast iron (ductile)	Case2- cast steel	Case3- cast bronze
Equivalent stress
equivalent strain
displacment
Locations for Possible Fracture

Inference from obtained Data (von-mesis stress theory is used)

• In the tabulation above the maximum value over the time span have been considered. The maximum vonmesis stress has exceeded the yield stress in all 3 cases therefore plastic deformations are inevitable. in such a case the material with least devotions from its yield stress will preferred
• Deviations
• Fracture will probably occur at the locations of highest von Mesis stress after a particular number of cycle of operations the fracture will create a crack that propagate throught the gear depending upon the fracture toughness stress intensity factore derived by irwin can be used to predict the life of the gear

Recommend Material: cast steel

The maximum stress usually occurs at the pinion gear (given that the material is ame for both pinion and gear), but when both the gear are of equal size stress are to be equal in both the gears under static conditions

But it can be observed from the von Mesis stress plot that the root of the driving gear tooth has the highest stress

Conclusion – it can be observed that cast steel is undergoing very small amount of stress generated. Hence cast steel would be best for manufacturing of spur gea