Week 1 Spur Gear Challenge

OBJECTIVE :- Write a detailed report comparing the results of the given three cases and conclude which material would you recommend based on these results.

• Case 1:
  

Using Cast Iron(ductile) as a material, carry out a static structural analysis to find out Equivalent stress, Total deformation and Stress intensity(Learn about what stress intensity is). Find location for possible fracture

• Case 2:

Using Cast Steel as material, perform the same analysis for the results as in Case 1.

• Case 3:

Using Cast Bronze as material, perform the same analysis for the results as in Case 1.

CASE SETUP:-

case1

• MATERAL - Cast Iron

• Assign material to the both components (LEFT & RIGHT)

• MESH - Created a mesh with 1mm

• CONTACTS - A frictional contact has to be set between the two spur gears, two avoid unnecessary complexity select necessary faces that comes into contact during simulation.

• JOINTS - Revolute joints are setup for the two gears w.r.t. ground. These joints needs to be apply boundary conditions to the gears.

• ANALYSIS SETTINGS - The analysis is setup for 6 steps. this doesn't control the time step, but it is only an indication of points where boundary conditions change. The time step is auto controlled by specifyng initial , minimum and maximum time steps.

• BOUNDARY CONDITIONS

A joint rotation is given to one revolution joint in increment of 30degrees for 6 steps.

this joint rotates against a moment load (10N-m) in the other revolute joint

• Follow the same procedure for case setup of case 2&3 ,use cast steel and cast bronze as materials for remainng cases

properties of cast steel

properties of cast bronze

RESULTS

case1- cast iron ,ductile

equivalent stress

total deformation

stress intensity

• stress intensity used in fracture mechanics. it predicts stress intensity near the tip of a crack caused by a remote load or residual stresses.
• stress intensity is defined as the absolute values of σ1-σ2, σ2-σ3, σ3-σ1
• The magnitude of stress intensity factor (K) depends on sample geometry, size and location of crack,magnitude and distribution of load.

stress intensity

case 2 - cast steel

equivalent stress

total deformation

stress intensity

case 3 - cast bronze

equivalent stress

total deformation

stress intensity

Comparing the results of the three cases

Factor of safety :-

• FOS is one of the key parameter for selection of material
• FOS < 1 is fail
• FOS between 2 to 5 is acceptable
• From the above table we can see that for all the cases the Equivalent stress has exceeded maximum yield strength (FOS < 1 ), which is where plastic deformation occurs.
• By considering the FOS data we can recommend cast iron ,ductile among remainng materials.

Google link

https://drive.google.com/file/d/1NGndtGiTLZ4xFJkn22u_eM5rmf9TcwLJ/view?usp=sharing