ME 314 (Design of Machinery) Class Information

Department of Mechanical Engineering

1. Syllabus and schedule.

A concise syllabus for ME 314 is available for download as a PDF file.

2. Mailing List.

There is a mailing list (listserv) titled ME314-L for this class. You may sign up at any time.

HOW TO SUBSCRIBE TO THE LIST:

Individuals can subscribe to the list by sending a message to: listserv@list.unm.edu

Leave the Subject field blank. In the body of message type (with no other text):

subscribe ME314-L Firstname Lastname

Once the subscribe request is approved, a notification will be emailed to the person.

3. ADAMS.

Material related to the ADAMS computational dynamics package will be here. In general, I'll be happy to discuss any ADAMS questions during class.

3.1 ADAMS Student Edition Available!!

After many years, there is FINALLY an ADAMS Student Edition, so you can use ADAMS on your own computers.

To download the MD ADAMS Student Edition, go to the MD ADAMS Student Center and follow the "Download Now" instructions. You'll have to scan your student ID somehow, but hopefully you can get it done.

3.2 ADAMS Guide (now with Table of Contents!)

Here is an ADAMS Guide I'm writing to help you in using ADAMS for this course. I first wrote this for the Fall 2009 course; made extensive additions during 2010, and I may do a little tweaking for 2011, but probably not too much more.

I added the "File/Import" step in importing cam data (that was a question in class)...it was my mistake in omitting it. Sorry!

I put a "time stamp" (currently FEB 21 @ 1605 MST) up in the header of this guide so you'll know if it's been changed; I'll also try to mention this in class.

The latest change is a correction to some wording in Section 3.3.2 about not specifying the length of the last link in building a 4-bar linkage, plus some typo corrections.

3.3 Steps in Constructing Problem 1.4

HERE are the steps in constructing the ADAMS model for Problem 1.4.

3.4 ADAMS/View "command" files.

ADAMS/View "cmd" files are MUCH smaller than "bin" files, and are a more convenient way to save models. These are actually text files, which is why they're small.

3.4.1 Problem 3.9 Here's the ADAMS/View CMD file for text Problem 3.9.. You will probably have to RIGHT-CLICK (or CTRL-CLICK on a Mac) this to save it as prob9.cmd.

We'll discuss this Problem 3.9 in class on Friday, February 5...particularly plotting results; which is in my Guide, Section 5.

3.4.2 Geneva Stop Mechanism and a GCON. Here's the ADAMS/View CMD file for the Geneva Stop Mechanism.

We'll discuss the Geneva Stop in class on Monday, February 8. To model the "pin in slot" constraint one must use the GCON (General Constraint) in ADAMS.

3.5 ADAMS/View CAM example.

I will go through the material in the ADAMS Guide Section 9 in class.

The data I will start with is in file cam.dat, as shown at the bottom of Section 9.2.2 in the ADAMS Guide. This is a different cam than is shown in Section 9 in the Guide, and is actually one of the "automotive" cams.

4. MATLAB.

We will use MATLAB occasionally during ME 314; presumably you have all had exposure to MATLAB before. I will be happy to answer any MATLAB questions during class.

Here is a MATLAB Tutorial prepared by the UNM Math Department (PDF file).

You can also go to the Mathworks' MATLAB & Simulink Based Tutorials...click on the "MATLAB Tutorial" to see a bunch of options. You may have to register for the main MATLAB tutorial, but it's free.

I suggest writing MATLAB Scripts (and functions where appropriate) to do things, and my one piece of advice is: COMMENT YOUR CODE!

5. Handouts.

Here are materials I've developed for the class.

Chapter 1 lectures: slide 1, slide 2, and slide 3.
Starr Section on Kinematics. (latest version SEP 23, 2011, 10:15 a.m., NOW with ACCELERATION) This is based on material from the legendary Thomas R. Kane, from the Applied Mechanics Department at Stanford University. I think it's much simpler than the methods presented in the text. I developed these notes for the Fall 2009 class; I'll probably change them incrementally for Fall 2011 as we go through the material.
Freudenstein's Equation for designing function-generator mechanisms. This is a clever method of synthesizing linkages to generate mathematical functions. This document is quite a bit more detailed than the discussion in the text. Updated to correct sign error in equation (11) as of October 16, 2011, 3:22 p.m.
Linkage Design Problem using Freudenstein's Method. This problem requires a fair bit of work; I meant to get it online well before Monday, October 10...sorry. It is NOW due on Monday, October 24. NOTE: I have changed the last function in the table (j, t last name) since the original one didn't work as well as I'd like.
How to Compute Cam Profiles. Geometry of the cam/follower contact and equations for computing the coordinates of a cam profile for a disk cam with a flatface translating follower. Now updated with minimum base circle radius analysis.
The MATLAB camprofile.m function. This function will generate the (x,y) coordinates of a cam profile.
The Cam Example from class. This is the combination of a cycloidal half-rise and a harmonic half-rise, where I matched yp (y^prime) and yppp. Now with algebra cleaned up a little.
The Cam Design MATLAB Script that I used to compute the displacement functions, etc. The output of this script can be used by camprofile.m to generate the [xc, yc] cam profile points that can then be plotted, and ultimately imported into ADAMS to build the cam.
The file cam.dat that I'm going to use for the ADAMS example in class on Friday, November 11. This is a harmonic rise of 1 inch in 120 deg of cam motion, then a harmonic return during the next 240 deg of cam motion. The minimum base circle Ro is 0.125 inch, but I used Ro = 0.5 inch to generate the data set in file "cam.dat"...I created and saved this file in MATLAB exactly like the "ADAMS Guide" Section 9.2. The MATLAB script to design this cam is in ADAMS Cam Design MATLAB Script.
Here's the article on Planetary Gear Trains from Machine Design magazine.

6. Homework "hints and answers."

Here are PDF and M-files containing hopefully helpful hints, some answers, and other information for the homework and programming assignments.

Chapter 1 Hints. You can use ADAMS on Problems 2 and 4 if you feel up to it. I built a cardboard model for Problem 1.16; also created an ADAMS model.
Chapter 3 HW I Hints. I decided to split the Chapter 3 HW into two assignments; this is part I. I gave you suggestions for all the problems, including all necessary geometry. This HW includes both analytical and ADAMS velocity analysis. I'd suggest starting the problems as soon as convenient.
Chapter 3 HW II Hints. I decided to split the Chapter 3 HW into two assignments; this is part II.
Acceleration HW Hints. I've just assigned Problem 3.15 and 3.23 again, but this time solving for some accelerations. Do these problems both analytically and with ADAMS. I now have a much more "complete" set of hints posted, along with some partial results. I will update these hints with more discussion and some more partial results when I get the problems completed.
Chapter 6 (CAM) Hints. I've requested that you do several more things on these three problems than the text requires, so please follow my guidelines. Problem 6.7 is a decent amount of work; don't put it off...due Wednesday, November 9.
Chapter 6 (CAM) HW Solution. Some people already had the HW solution and some didn't. Now we're all equal.
Chapter 7 (and 9) Hints. These are all text problems, plus the "Starr Problem" on a planetary overdrive. Due on Friday, December 2. NOTE: In Figure 9.4 (Starr Problem 1) the number of teeth of gear 3 should be 42, not 22.
Chapter 7 and 9 (gears) HW Solution.

8. Exams.

Here is some information about Exam II, to be on Friday, December 9, 2011

Open-Book, but nothing else (no notes, HW solutions, etc.)
Coverage: all material we have covered since the last exam
First page: concepts, short-answer, multiple choice, etc.
Second page: cam problem
Third page: gear problem