ME 383 - Analysis of Mechanical Design

Sample Syllabus

Winter, 1994
Ullman/Reiter

Class Hours:

Lecture

MWF 11:30-12:50

Studios

Thursday 9:30-11:20 or

Friday 1:30-3:20 or

11:30-13:20 or

14:30-16:20

Objective

In ME 382 we emphasized techniques to develop original designs. In this course we will consider the redesign of an existing product. Further, ME 382 emphasized creativity and the generation of products and in this course we will stress the evaluation of mechanical objects.

Specifically, in this course we will study analysis techniques used to predict a component's failure and/or factor of safety. This course is more analytical than ME 382.

The structure of the course will be as follows. The course is built around a term project to reverse engineer and redesign an existing product. In lecture we will be talking about some of the techniques necessary to evaluate this product. The lectures will cover only part of the information needed to solve the design problem. The remainder of the information you need will come from unassigned portions of the text or from your independent library readings.

Text

• Mechanical Engineering Design, 5th edition, Shigley and Mischke, McGraw Hill.
• Plus other assigned readings.

Grading

• Homework 20%
• Midterm 1 20%
• Midterm 2 20%
• Project
  • Written Report 20%
  • Oral Report 10%
  • Display Model 10%
• Total 100%

Homework is due the Wednesday following its assignment. Note all assumptions on the homework with a red letter "A".

Project

To develop an understanding of existing mechanical devices and how to analytically evaluate them you will select, reverse engineer and redesign an existing product or product assembly. The steps of this project are as follows:

1. Be assigned to a team.
2. Select a mechanical device for study. Your team will select a mechanical power transmission system or kinematic linkage to study during the term. You must be able to get a sample of the device selected. Further, an assembly manual, service manual or other documentation on the device is helpful. The device must have at least 5 moving parts. Final approval will be given by one of the instructors.
3. Disassemble the device. Take it apart, clean it and understand how it works.
4. Generate QFD and DFA for the device. You may have to guess at much of the information. Note all assumptions made.
5. Create free body diagrams of the device in all critical operating modes. The free body diagrams must be of the entire device and all the major components. To do this will require characterization of the power source(s), losses and loads.
6. Find the stress at critical points in the device. You must find the three of the most critical points. Some of these may be critical in terms of stiffness rather than stress.
7. At each point analyze the stress and/or deflection of the system.
8. Evaluate the life of the product based on fatigue or fracture at these critical points.
9. Evaluate the life for other failure modes such as wear and corrosion.
10. Compare the device to the requirements in the QFD. Based on this comparison, an assessment of the quality of the design should be developed. Areas where quality could be improved, assembly made easier or cost reduces should be itemized and discussed.
11. Estimate the material and manufacturing processes.
12. Redesign the three most critical points.
13. Improve the DFA score.
14. Prepare Drawings of selected parts and assemblies of the device. Details on this will be developed in class.

Your team's effort will be evaluated in three ways:

1. A written report. This must contain the following sections:
   1. An executive summary
   2. Introduction to the device studied
   3. Description of the device studied
   4. The 14 items above.
   5. Conclusions and Recommendations
   6. Appendices with detailed analysis and drawings
   The report should be typewritten but equations can be hand written. Note that any calculations that are not accompanied by text to explain them and the associated assumptions will be disregarded.
2. An Oral report all the group members will describe the operation and design of the device. Reports will be 15 minutes long and will make use of professional quality visual materials and demonstrations. All team members must take part in the presentation.
3. A Display model Your device will be modified so that the internal parts are visible and the operation demonstrated. The model will be mounted for display. Diagrams and text describing the system and its operation will be plastic laminated and accompany the display model.

Syllabus:

Week 1: Jan 3 - 7

Topics:

• Introduction to this course
• Introduction to the design problem
• Review of equilibrium
• Factor of Safety

Suggested Readings:

• Chapters 1,2-1 through 2-14

Homework:

• 2-15b, 2-16c, 2-27 a,b,e

Week 2: Jan 10 - 14

Topics:

• Strong shape vs weak shapes
• critical points (review stress flow)
• Review of stress and strain
• review of deflection and stiffness
• Designview program

Suggested Readings:

• Chapter 3 skip 3-4, 3-5 and 3-12

Homework:

• 3-8, 3-14, 3-38, 3-48

Week 3: Jan 17 - 21 (No class on Jan 17)

Topics:

• Static Failure theories both traditional and fracture based
• Static shaft design

Suggested Readings:

• Chapter 6 through 6-10 and 5-21 to 5-26

Homework:

• 6-8, 6-14, fracture problem

Weeks 4 and 5: Jan 24 - 28, Jan 31- Feb 4

Topics:

• fatigue failure theories both traditional and fracture based
• rotating shaft design

Suggested Readings:

• week 4 Chapter 7
• week 5 Chapter 18 through 18.8

Homework:

• Week 4: 7-9, 7-11, 7-21
• Week 5: 18-2, 18-7, fracture problem

Week 6: Feb 7 - 11

Topics:

• Fastener selection
• Introduction to Feature Based Design
• Introduction to Geometric Dimensioning and Tolerancing

Suggested Readings:

• Sections 8-1, 8-3, 8-16 and 8-17
• Handout

Homework:

• to be announced

Week 7: Feb 14 -18

Topics:

• introduction to welds and adhesives
• GD&T symbols and drawings

Suggested Readings:

• Section 9-1
• Handout

Homework:

• to be announced

Week 8: Feb 21- 25

Topics:

• gear selection
• gear set design
• field trip to Linn Gear
• Datums and datum features

Suggested Readings:

• Sections 13-1, 13-2, 13-8, 13-9, 13-10, 13-11
• Handout

Homework:

• to be announced

Week 9: Feb 28 - Mar 4

Topics:

• bearing selection
• basic dimensions

Suggested Readings:

• Sections 11-1, 11-6, 11-7,11-10
• Handout

Homework:

• to be announced

Week 10: Mar 7 -11

Topics:

Suggested Readings:

Homework: