Reference no: EM133118676

Stress and modal analyses - limitations, assumptions and objectives

EMA objectives

1. To determine the deflections and stresses sustained by the shaft in its operating conditions, including the magnitudes and locations of the maximum stress values.

2. To determine the minimum shaft wall thickness based the results of your analysis and the maximum allowable deflection and stress.

3. To discuss the effect of using a steel with a higher yield strength on the deflection and minimum thickness of the cutting shaft.

4. To determine the first four normal modes of natural vibration of your chosen shaft in the absence of loadings (i.e. free spinning).

5. To prepare a full report of the analysis strategy, the results and their implications, not exceeding 20 pages including all pictures and tables.

Report requirements and structure

You must submit a detailed report on your project analysis. We expect to see details of all the assumptions you make, your modelling strategy including selection of suitable FE element(s), verification trials and details of validation processes, etc. You are advised to conduct several analyses, fine-tuning your model to provide valid modelling of important details, such as any stress raisers, until you are satisfied that the FE results are meaningful and consistent with the mathematical hand calculations.

The general format of your report could be as follows:

Title page

This page should include your name, personal identifier and a statement such as:

‘This document has been prepared by and represents his/her own work.'

Executive summary
This should summarise the main aims of the analysis and its conclusions in no more than one page.

Notation
A list of symbols and/or explanation of terminology used.

Table of contents
A detailed list of all sections and sub-sections with page numbers.

Introduction
Introduces the problem and sets out aims and objectives and perhaps some background. Also, perhaps gives your approach to the analysis.

Analysis (key section)
This is the main body of the report, which should include descriptions of the modelling process, selection of element types, meshing, refinements, model limitations, etc.

Also, importantly, you should include the assumptions you have made or invoked, material properties, boundary conditions tried and specified, loading conditions, etc.

Effectively there will be two parts here covering:

1. the stress and deflection analysis
2. the modal analysis.

For both there should be serious attempts at verification calculations (i.e. mathematical hand calculations) and comments on the validity of your models and results obtained.

Discussion and conclusions
You should have a discussion section on your approach to the tasks, any problems or issues you may have encountered and the significance of the results and their validity, and what they may mean in the context of the machine operation. Finally, you need to confirm that you have done all you set out to do and all that the project brief requires, and possibly recommendations for further work if you had the time and resources.

Attachment:- Stress and modal analyses.rar