STATIC STRUCTURAL ANALYSIS ON SPUR GEAR
Objective :
The objective is to simulate static structural analysis on spur gear with three different materials (cast iron(ductile), cast steel and cast bronze) and compare their Total deformation, Equivalent stress(von Mises), Stress Intensity and find the location of the fracture.
SPUR GEAR :
CAD model of spur gear
The below figure shows the steps followed to run the simulation.
SIMULATION SETUP :
The below pre-processing steps are followed for all cases.
CONTACT SETUP :
Frictional Contact has been set between two spur gears which would be interacting at the interface which has been set to adjust to touch as shown below.The behaviour of the contact is behaviour and the formulation of contact is set as Augmented Lagrange.
Frictional contact
JOINTS SETUP :
Revolute joints were added to each spur with connection type body-to-ground which is just the frame of reference we use. Joint load, rotation and moment are given to right and left gear respectively in 6-time step. As shown in the figure below is shown that right gear(A) is given a rotation of 180 degrees and left gear(B) is given the moment of -10 N-m.
The below figure shows the analysis settings followed for all cases.
Analysis settings
Joint loads
MESHING SETUP :
CAD Model is meshed with an element size of 1 mm to keep the elements/nodes 32k which is the maximum limit for the academic version of the software which resulted in 17860 nodes and 3088 elements are shown below.
Meshed model
SIMULATION RESULTS :
CASE-1 : Cast Iron(ductile)
properties of cast iron(ductile)
Total Deformation of material cast iron
Total deformation vs time graph
Total deformation table
Equivalent stress of cast iron
stress vs time graph
Equivalent stress table
STRESS INTENSITY :
The stress intensity factor (K), is used in fracture mechanics to predict the stress state (\"stress intensity\") near the tip of a crack or notch caused by a remote load or residual stresses.
Stress intensity is defined as the largest of the absolute values of σ1 - σ2, σ2 - σ3, or σ3 - σ1:
![](\"https://ansyshelp.ansys.com/Views/Secured/corp/v194/wb_sim/graphics/eq059a1e89-1f03-4d3b-b8cd-20a1ebfb92a2.svg\")
Stress intensity of cast iron
stress intensity vs time graph
Contact pressure
pressure vs time graph
CASE-2 : Cast steel
properties of cast steel
Total deformation of cast steel
Equivalent stress of cast steel
stress intensity of cast steel
Contact pressure
CASE-3 : Cast bronze
properties of cast bronze
Total deformation of cast bronze
Equivalent stress of cast bronze
stress intensity of cast bronze
Contact pressure
contact pressure table
Possible Fracture :
Animations link :
https://drive.google.com/drive/folders/1Al6hgT9fBTPoxLqpBueDXgs2CvMAwbWU
The Comparison between each case is shown in the table below with the maximum value of total deformation, equivalent stress and stress intensity in spur gear.
Result Table
CONCLUSION :
From above we can see that for all the case the Equivalent stress has exceeded maximum yield strength, which is where plastic deformation occurs and the place where the fracture occurs is where there is maximum equivalent stress.
we cannot consider cast bronze because stress intensity has exceeded the maximum ultimate strength. So the recommended material would be cast iron because its stress intensity is less compared to cast steel and also its equivalent stress is less.