Metal Fatigue Excel Calculations

John Andrew, P.E.


Course Outline

Metal Fatigue Excel Calculations, is a 5 Professional Development Hour (PDH) online course having a series of input fatigue data and solved output equations in an Excel format. The student will type numerical values for machine design parameters and Excel will perform the calculations. For example, the proposed, time varying reversing loads on a shaft, are typed into labeled cells and the shaft diameter that will withstand the fatigue loading will be calculated for any safety factor.

Or any input parameter can be found for a target value of an Excel calculated item by using the "Goal Seek" tool in Excel.

The course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the conclusion of this course the student will:

Intended Audience

The information will be especially useful to students, engineers, and innovators who need tools for creative machine designs subjected to fatigue loads.


Benefit to Attendees

Attendee of this course will be able to calculate and optimize variables in a useful range of machine fatigue design projects.


Course Introduction

Machine design calculations have been done with a calculator and written by hand with pen or pencil. Optimizing design values with a calculator is difficult and time consuming. Quite often it is impossible to read and check these hand written documents. As time passes it becomes more difficult to find and use these documents to make improvements to existing designs. However, Excel spread sheets out-perform hand calculations and provide readable electronic and hard copy permanent records. Excel spread sheets are used to calculate and optimize machine design parameters more easily.


Course Content

This 5 hour online course defines the design equations of several basic examples of machine component subjected to cyclic loading resulting in Excel print-outs of design parameters and calculated results.

The Excel Workbook spread sheets are:

Tab 1 Definitions
Tab 2 S-N Curve
Tab 3 Notches
Tab 4 Cantalever-1
Tab 5 Cantalever-2
Tab 6 Shafts

Definitions:
Conversions of conventional US engineering units and International Standard units useful for fatigue calculations are provided. Principal stresses, strength and fatigue failure theories, distortion energy or von Mises-Henky theory are presented. Shear yield stress is calculated from the ultimate tensile strength of most steel alloys.

S-N Curve
Fully reversed, repeated, and fluctuating stresses are defined. Fatigue correction factors are calculated for: load, size, surface finish, temperature, and reliability. Fatigue endurance, Stress VS number of cycles, S-N graphs are plotted.

Notches
Static and fatigue endurance stress concentration factors for stepped shafts and flat plates are estimated. Rectangular and round section properties are calculated.

Cantalever-1
A cantilever bracket with notches, subjected to fully reversed bending stress, is analyzed for fatigue endurance.

Cantalever-2
A cantilever bracket with notches, subjected to fluctuating bending stress, is analyzed for fatigue endurance.

Shafts
Two examples of fatigue bending and torsion of power transmission shafting is estimated.


You need to download and study the following spreadsheet:

Metal Fatigue Excel Calculations

DISCLAMER: "This spreadsheet is provided for illustrative teaching purpose only, and is not intended for use in any specific project. Anyone making use of theinformation contained in this spreadsheet does so at his/her own risk and assumes any and all resulting liability arising therefrom."


Course Summary

This course provides Excel spread sheets to calculate a useful range of basic machine fatigue design parameters. All variables can be adjusted to optimize design goals. Excel print-outs of design parameters and calculated results provide easy to read documentation for checking and future improvements.

Related Links

Go to: http://www.PDHonline.com for PDH Course M236 - Machine Design Excel Calculations.

430,000 machine items are described and priced at: http://www.mcmaster.com

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

Take a Quiz


DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.