STRUCTURAL ANALYSIS OF A SPUR GEAR
AIM:
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.
STRUCTURAL ANALYSIS:
- Structural analysis is the process of calculating and determining the effects of loads and internal forces on a structure or an object.
NEED FOR STRUCTURAL ANALYSIS:
- Structural Analysis is particularly important to understand the load paths and the impacts the loads have on engineering design.
- It allows engineers to ensure a piece of equipment or structure is safe for use under the estimated loads it is expected to withstand.
STRESS INTENSITY:
- Stress intensity is used to predict the stress state near the tip of the crack or notch caused by a remote load or residual stress
- It is usefull for providing a failure criterion for brittle materials.
- it is denoted by K.
CASE SETUP 1: CAST IRON, DUCTILE
MATERIAL PROPERTIES OF CAST IRON
PROCEDURE FOR IMPORTING THE SPUR GEAR MODEL:
- Assign the material type to the spur gear to be imported using the tool Engineering data-Edit-Engineering data sources-Granta design sample materials-Cast iron, ductile
- Import the spur gear.stp file using the tool Geometry-import-spur gear.stp
PROCEDURE FOR STRUCTURAL ANALYSIS:
- Update the model to work on the model for structural analysis
- Under Model-geometry assign the name for the two spur gears based on their position as left and right.
- Under Contacts sub menu select the faces of both contact and target spur gears which intersect with each other.
- Under Contacts sub menu create joints option separately for each spur gear to specify their connection type as body-ground.
- Mesh the model by assigning the elemant size as 1mm
- Under static analysis in analysis setting sub menu setup the controls as shown in the image below
- Under static analysis menu create two joint sub menu for each spur gear for specifying their rotation degrees in anticlockwise direction and moment values in clockwise direction.
- Insert the total deformation, von mises stress solution and stress intensity to analyse the solution of spur gear. Then press f5 to solve.
TOTAL DEFORMATION
TOTAL DEFORMATION GRAPH
VON-MISES STRESS
STRESS INTENSITY
CONTACT PRESSURE
CASE SETUP 2: CAST STEEL
- Once the setup has been done then the structural analysis for different materials can be done simply canging the material properties under geometry menu
MATERIAL PROPERTIES OF CAST STEEL
TOTAL DEFORMATION
DEFORMATION GRAPH
VON-MISES STRESS
STRESS INTENSITY
CONTACT PRESSURE
CASE SETUP 3: CAST BRONZE
MATERIAL PROPERTIES OF CAST BRONZE
TOTAL DEFORMATION
DEFORMATION GRAPH
VON-MISES STRESS
STRESS INTENSITY
CONTACT PRESSURE
COMPARISON OF RESULTS OF THE ABOVE ANALYSIS:
- From above results the total deformation value for the all the three case setups are same 30mm.
- The cast bronze material case setup has the minimum equivalent stress value i.e., 321.64 Mpa with a difference of 0.45 Mpa when compared with cast iron material case setup and a difference of 0.56 Mpa when compared with cast steel material case setup.
- The cast iron material case setup has the minimum stress intensity i.e., 329.91 Mpa with a difference of 1.6 Mpa when compared with cast steel material case setup and a difference of 3.52 Mpa when compared with cast bronze material case setup.
- The cast iron material case setup has the minimum material density i.e., 7130 Kg m^-3 with a difference of 690 Kg m^-3 when compared with cast steel material case setup and a difference of 1680 Kg m^-3 when compared with cast bronze material case setup.
CONCLUSION:
From the above discussions though Cast iron material case setup has least material density and stress intensity it does not compromise its analysis results when compared with other two case setup. Hence spur gear made of cast iron material should be preferred.