Spur Gear Analysis

Stress intensity :The stress intensity, K1, represents the level of \"stress\" at the tip of the crack and the fracture toughness, Kic, is the highest value of stress intensity that a material under very specific (plane-strain) conditions that a material can withstand without fracture. As the stress intensity factor reaches the Kic value, unstable fracture occurs.

Engineers are interested in the maximum stress near the crack tip and whether it exceeds the fracture toughness. Thus, the stress intensity factor K is commonly expressed in terms of
the applied stresses o- at r —) o and 0 =o .

For example, for a through crack in an infinite plate under uniform tension a , the stress intensity factor is

where a is one half of the width of the through crack. The dimension of K is

In the last few decades, many closed-form solutions of the stress intensity factor K for simple configurations were derived. Some of the common ones are listed in the following three categories: classic, specimen, and structure.

Objectives:-

To carry out a static structural analysis over spur gear considering three different case setups to find out Equivalent stress, Total deformation and Stress intensity.And find location for possible fracture in three materials

1. Cast iron Ductile

2. Cast steel

3. Cast bronze

Geometry:- Spur gear geometry imported from provided file

Selection of Material:-

Case1:- Cast Iron (Ductile)Case2:-Cast SteelCase3:-Cast Bronze

Contacts:- The contact type provided is frictional with the mating surfaces of gears selected as Contact and Target. The Behaviour is changed to symmetric and the Formulation type used is Augmented Lagrange. The interface treatment is set to Adjust to Touch. Connection of Gear:-

Joints:-The joints are set to ground to body and they revolve around axisjoint load:-

joint moments:-

Meshing:-

Mesh quality

Mesh Metrics:-Total Deformation:-

Case1:-Cast Iron DuctileAnimation:-link(https://youtu.be/_xKJK3lmFzM)

Case2:- Cast BronzeAnimation:-(https://youtu.be/RR5NOhxVyV8)

Case3:-Cast SteelAnimation:-(https://youtu.be/0ppSF2zf6QY)

Equivalent Stress:-

Case1:-Cast Iron DuctileAnimation:-(https://youtu.be/oaGC5b2shRc)

Case2:-Cast BronzeAnimation:-(https://youtu.be/lNtvdbzrg_8)

Case3:-Cast SteelAnimation:-(https://youtu.be/iE2wAsQUI2E)

Stress Intensity:-

Case1:-Cast Iron DuctileAnimation:-(https://youtu.be/1GiaiJshiR4)

Case2:-Cast BronzeAnimation:-(https://youtu.be/oaps0RX-oz8)

Case3:-Cast SteelAnimation:-(https://youtu.be/Ml30QlHT394)

Comparision Between 3 Materials of Gears.

Conclusion :-

Location of Fracture : The crack is approximated to initiated at gear root and land of the mating tooth. This leads to maximum Stress Intesnity and thus fracture is approximated to occur at this location.

Sr.No.	Materials	Equivalent Stress	Total Deformation	Stress Intensity
		(Mpa)	(mm)	(Mpa)
1	Cast Iron (Ductile)	Max.=327.54	Max.=30	Max.=335.5
		Min.=1.5042e-5	Min.=18.5	Min. =1.6784e-5
2	Cast Steel	Max.=326.95	Max.=30	Max. =336.4Mpa
		Min.=2.5841e-005	Min.=18.5	Min. = 2.8908e-005
3	Cast Bronze	Max.=318.54	Max.=30	Max. =330.23
		Min.=9.4157e-007	Min.=18.5	Min. =9.9606e-7

1. From Above compression :- Equivalent Stress :- 1>2>3
Total Deformation :- 2=1=3
Stress Intensity :- 2>1>3
2. As per my analysis done in Ansys, and comparing the above results, I prefer Cast Iron
material for manufacturing of the gear because it gives less Equivalent Stress at the time of
functioning.
3. Apart from that we also can choose Cast Bronze material for the manufacturing of the
gears because it gives less Stress Intensity where the crack initation is started.

As Visible from the results Stress Intensity is maximum in CAST STEEL there for it is very likely to fail under same loading. So Cast Bronze should be used for usage. But Cast bronze is very costly. So considering both the factors I would recommend using Cast Iron which is economically feasible and having Stress Intensity in between both Cast Steel and Cast Bronze.