Actually, I'm having trouble implementing the plot of the flutter region for the whirl prop system with 2 DOF (Influences of structural damping and propeller—pivot point distance on whirl flutter stability) and My plot isn't getting a hump.
However, What I am most doubtful about is the method of calculating the moment of inertia of the rotor disk, angular frequency and torsional Stiffnesses. But not sure if the length of the pylon and the radius of a rotor disk impact the angular frequency or stiffness.
Attached you can check my MATLAB script.
I would highly appreciate any suggestions you might have
Nikoo Etemadi
step-by-step:
1. **Moment of Inertia of Rotor Disk**: The moment of inertia of the rotor disk depends on the mass distribution of the disk. For a uniform circular disk, the moment of inertia is calculated as:
```
I = (1/2) * m * r^2
```
Where:
- `m` is the mass of the rotor disk
- `r` is the radius of the rotor disk
The length of the pylon and the radius of the rotor disk do not directly impact the moment of inertia calculation. The moment of inertia is a property of the rotor disk itself.
2. **Angular Frequency**: The angular frequency of the rotor system depends on both the stiffness and the moment of inertia. The general formula for the natural angular frequency `ω` is:
```
ω = sqrt(k/I)
```
Where:
- `k` is the stiffness (torsional, bending, etc.) of the system
- `I` is the moment of inertia of the rotor disk
The length of the pylon and the radius of the rotor disk can impact the stiffness `k` of the system, which in turn affects the angular frequency `ω`. Longer pylons or larger rotor disks may change the overall stiffness of the system.
3. **Torsional Stiffness**: The torsional stiffness `k` depends on the material properties and geometry of the components in the system. For a simple torsional spring, the stiffness can be calculated as:
```
k = (G * J) / L
```
Where:
- `G` is the shear modulus of the material
- `J` is the polar moment of inertia of the cross-section
- `L` is the length of the torsional member
The length of the pylon and the radius of the rotor disk can impact the torsional stiffness `k` through the length `L` term in the equation.
As for the "hump" in the plot of the flutter region, this likely depends on the specific parameters and coupling between the structural damping and propeller-pivot point distance in your 2 DOF whirl flutter model. You may need to review your model assumptions, parameter values, and calculation methods to understand why the expected hump is not appearing. Try refining your parameters
Good luck! partial credit AI