Modal Analysis of Crank Shaft Using Beam Equivalent Model

FEM PROJECT

CRANK SHAFT ANALYSIS

Problem: Modal analysis and harmonic loading analysis of crankshaft using beam model

In this problem, we converted a 3D element to a beam model element as  it is easy to compute and gives pretty much accurate results.

The following 3 D model was used as a reference and we equated moment of inertia of the 3 d model elements and beam elements to get the reff for the beam model.

[pic 1]

The following pictures depict the formulae used for getting the reff.

The FEM analysis is explained via the following pictures:

Part :

 Make a line of 320 mm in part

Properties:  We used grey cast Iron as the component .

Insert the properties  

Density = 7200 kg/m3

Young’s modulus = 6.62e10

Poisson’s ratio = .27

Create section:

Select a section and select it as beam

Assigned section to it

Similarly do for the other parts created by edge partition of initial length

Assign beam orientation:

Click assign beam orientation and select the whole line

Assembly:

Go to assembly and click to create instance and select bar then ok

STEP :

FOR FIRST 20 NATURAL FREQUENCY

BOUNDARY CONDITIONS:

FIXING THE BOTH ENDS OF THE CRANK SHAFT

     MESHING :

 VISULIZATION:

FIRST MODE (280.17)

 SECOND MODE ():                                                                                                                                                                                            

THIRD MODE(2358.1):

FOURTH MODE(2620.3):

IFTH MODE(5042.6):

SIXTH MODE(6356.7):

SEVENTH MODE(8530.1):

...