ANSYS SOFTWARE WORK

MMAE 545- Project #2

Due Sunday 04/30/2023 at Midnight

Note: You can work on this project individually or as a group of two.

Project Goal: Design an aluminum-bladed disk with a minimum weight that operates at a rotational

speed of 4,500 𝑅𝑃𝑀.

The following information applies to your design:

- The disk has 24 blades.

- The disk has an outer radius of 15.0 inches.

- The distance from rotational center to blade tip is 24.0 inches.

- The disk is rigidly connected to a hollow rotation shaft, which is also aluminum. The

shaft has an inner radius of 1.0” and an outer radius of 2.0”. Model an 8.0” length of

the shaft, with the ends having fixed displacements in all DOF.

- The material modulus is 10.5𝐸6 𝑝𝑠𝑖, the weight per unit volume is 0.095 𝑙𝑏𝑠/𝑖𝑛3, and

Poisson’s ratio is 0.34. The yield strength is 35,000 𝑝𝑠𝑖.

- The maximum allowable radial deflection at the tip of a blade is 0.015”.

- The minimum required safety factor regarding yielding is 2.0, where the safety factor

is calculated by comparing the material yield strength to the maximum von Mises stress

calculated in part.

- Only one sector of the system is actually modeled, with cycling symmetry boundary

conditions applied.

- For more information on the geometry, including restrictions on the geometry, review

the figures and notes on the last pages of this handout.

In a real-world application, there may be other concerns. However, in this project, your design

goals only require you to consider the maximum stress and deflection constraints listed above.

Submit a document named XXXX-(XXXX)proj2.pdf, where “XXXX-(XXXX)” are the first four

letters of each group member.

The final report should include the following sections

 Brief Introduction

 Modeling and Optimization procedures

 Results and Discussion

 Conclusion

You may want to include the following items into the above four sections:

 Total part weight, in pounds

 Largest radial direction deflection (in inches) at the blade tip at the operating speed of

4500 𝑅𝑃𝑀.

 Largest von Mises stress in part at the operation speed of 4500 𝑅𝑃𝑀.

 The first four undamped natural frequencies of your system based on a prestressed

modal analysis at the operating speed of 4500 𝑅𝑃𝑀. You have no design requirements

in this project to satisfy related to natural frequencies, but you need to list the lowest

four natural frequencies.

 Largest radial deflection (in inches) at the blade tip if you final design were operated

at 9000 𝑅𝑃𝑀. Your design is not required to satisfy any deflection requirements at this

speed.

 Largest von Mises stress in the part at the operating speed of 9000 𝑅𝑃𝑀. Your design

is not required to satisfy any stress requirements at this speed.

 The first four undamped natural frequencies of your system based on prestressed modal

analysis at an operating speed of only 9000 𝑅𝑃𝑀. Again, you have no design

requirements in this project to satisfy related to natural frequencies.

Submit your document and also a Workbench archive file of your project with you final solved

model for your final design at 4500 𝑅𝑃𝑀. Name the archive file XXXX-(XXXX)proj2.wbpz.

Your grade will depend, in part, on minimizing the weight. Of course, all design criteria, including

dimensional constraints, must be met. You should be sure your mesh is adequate to accurately

predict the maximum von Mises stress and your design deflections.

Consider the figures and notes on the following page. Note that there is a symmetry plane

perpendicular to the Z axis in the example model (see X-Y-Z coordinates at the bottom right of

the bottom figure). You may choose to take advantage of this symmetry in your model to calculate

the stresses and deflections if needed due to model size limitations with the student edition of

ANSYS. It is important that you use a fine enough mesh to get accurate predictions for your

deflections and stresses at 4500 𝑅𝑃𝑀. So, if a mesh convergence study shows that your version

of ANSYS doesn’t allow for a fine enough mesh in modeling the full sector, then model half the

sector in calculating deflection and stresses, using the symmetry about the XY plane.

Your modal analysis results must be based on the full sector, not half of the sector, because the

symmetry boundary condition above could affect the modal analysis results. Not all mode shapes

may be symmetric about the XY plane. But, if needed, you may use a coarser mesh for the modal

analysis.