MET 311 
3 CREDITS
Fall 2014 






TEXT: 
Strain Measurements and Stress Analysis by Khan and Wang 


PREREQUISITE: 
Grade of C or better in MET 211 


INSTRUCTOR: 
Mark French 


OFFICE HOURS: 
8:00 – 10:00 MF 


OFFICE LOCATION: 
121 Knoy Hall, Desk: 7654947521 Cell: 7657149382 


EMAIL CONTACT: 


LECTURE LOCATION: 
ME 1051 


LECTURE TIMES: 
TTh 9:30 – 10:20 


LABORATORY LOCATION: 
Knoy Hall, Room 106 


LABORATORY TIME: 
Sec 1: T 3:30 – 5:20 Sec 2: W 3:30 – 5:20 





A: 
> 90% 
Exam 1 
20% 
B: 
80%  90% 
Exam 2 
20% 
C: 
70%  80% 
Homework: 
15% 
D: 
60%  70% 
Labs: 
20% 
F: 
< 60% 
Project: 
25% 


Week 
Date 
Topic 
Reading 
Homework 




Homeworks are due one week after the day they are assigned 
1 
8/26 
Class Intro, Strength of Materials Review Axial Stress and Deformation Torsional Deformation 



8/28 
Strength of Materials Review Stress and Strain Material Properties Beam in Bending LoadShearMoment Diagrams 


No Lab in Week 1 



2 
9/2 
Strength of Materials Review · Combined Stresses · Stress Concentration 
HW #1: Wing Strut Loads
Due: 9/9 

9/4 
Strength of Materials Review Long Column Buckling Short Column Buckling 




Lab 1 – Acceleration of Gravity 
It might help to have examples of technical articles to review as you write your reports. Here are some that appeared in a journal called Experimental Techniques. A Conical Laser Vibrometer Mirror 


3 
9/9 
Introduction to Mathcad 



9/11 
Strength of Materials Review Mathcad Review 

HW #2: Combined Stress 1  For structure in Problem 1, compute stress along the top of the beam for each pin position. Assume the beam is 1” wide and 8” high. Find only the stress on the upper surface of the beam Due: 9/18


Lab 2 – Measurement Variation 



4 
9/16 
End of Strength of Materials Review Pressure Vessels

HW #3: Buckling For structure in problem 1, find minimum weight strut for each pin position Information on Streamlined Tubing Tensile equivalent is based on crosssectional area. Compressive equivalent is based on area moment of inertia. Due: 9/23 


9/18 
Chapter 2 
HW #4: Buckling and Pressure Vessels (Use K=2) also, assume material is stainless steel  yield stress is 400 MPa and E=190 GPa. The wall thickness is 1.0mm Due: 9/25 



Lab 3  Measuring Area Moment of Inertia 


5 
9/23 
Strain Gauges 



9/25 
Bridge Circuits 

HW #5: 2.4, 2.6
Due: 10/2 

Lab 4 – Making Bridge Circuits 


6 
9/30 
Bridge Circuits 


10/2 
Bridge Circuits with Two Gauges 

HW #6: Half bridge with strains due to load and to thermal expansion
Due: 10/9



Lab 5 Continued – Adding OpAmps 


7 
10/7 
Semester Project Description Effect of Long Lead Wires 
Bridge:
able to support a load of about 210lb in the middle. That means I will be standing on it. I wear size 12W shoes and there has to be a
place for me to stand comfortably Constraints: 1)
Bridge must be portable 2)
There must be 2m of clear space between the end supports 3)
Bridge cannot touch floor between the supports 4)
An upright 2L Diet Coke bottle must be able to pass under the bridge anywhere
in the central 1m portion of the bridge (while load is applied) 5)
The bridge must support the load (me) for at least 20 seconds 6)
Any materials are allowed as long as they are safe and legal (for example, no
uranium/baby seal composites) Grading
Criteria: Analysis 25% Design 20% Strength 20% Weight 20% Aesthetics 15% 
HW #7: 1. Fig P3.2 (p 88). If R_{g}=350Ω, V_{in}=12V and ε = 500μ, find V_{out} (Note: for this problem, use the resistance values shown in Fig P3.2) 2. If all four gauges have R=350Ω, find V_{out} 3. If all four gauges have R=120Ω, find V_{out} 4. All four gauges have R=120Ω and the active gauge is mounted on an aluminum bar. If the temperature rises 40°C and no load is applied, find V_{out} _{ } Due: 10/21 
10/9 
Strain Gauge Rosettes 


Lab 6 Continued – Adding OpAmps 


8 
10/14 
Fall Break 


10/16 
Von Mises Stress 
Section 3.4 and 3.5 
HW #8 3.16, 3.17, Max Force Problem For the Max Force Problem: What are the strains in the XY direction (ε_{x}, ε_{y}, γ_{xy})? What are the strains recorded by the gauges (ε_{A}, ε_{B}, ε_{C})? Due: 10/24 



Lab 7 – Measuring Elastic Modulus using Wave Propagation 


9 
10/21 
Exam Review 


10/23 
No Class 





No Lab 


10 
10/28 
Exam 1 
In Class, Open Book, Open Notes Sample Exam from Fall 2006:


10/30 
Dynamic Data · Aliasing · Filtering · Sample · Rates · Resolution Lowpass filter to avoid aliasing 

HW #9 1. If an accelerometer is recorded at a sample rate, f_{s}, of 1000 Hz, what is the maximum frequency that could be observed? 2. If a first order lowpass filter is to be used as antialiasing filter for problem 1and it has a resistor of 100kΩ, what capacitance does it need? Set the corner frequency to the maximum possible. 3. If you record an accelerometer with f_{s}=2560 Hz and a sample time T=10 seconds, what is the frequency resolution? 4. If f_{s}=12800, what is the time resolution? 5. Say you are recording the dynamic output from a strain gauge and you need the frequency resolution to be 0.125 Hz and the time resolution to be 0.25 sec. What are the required sample frequency and sample time? Due: 11/11 


Lab 8 – Speed of Sound in Solid Bar, Demo and Software Install 


11 
11/4 
Dynamic Data using Matlab High Pass and Low pass Filters Importing Data 



11/6 
Dynamic Data Using Matlab Piston Slap Example 



Lab 8 Continued – Speed of Sound in Solid Bar 


12 
11/11 
Review of Data Acquisition Rotating Equipment Ordinal Domain 



11/13 
Beam Bending Frequencies 




Lab 9 –
Measuring Beam Bending Frequencies 


13 
11/18 
Optical Testing 

HW #10 1 Master grating pitch = 50 lines/in. Find fringe spacing when rotation angle is 5°, 10° and 15° 2 Master grating pitch = 100 lines/in. Find fringe spacing when rotation angle is 5°, 10° and 15° 3 If the master grating pitch is 50 lines/inch and the specimen pitch is 55 lines/in, what is the fringe spacing (no strain)? 4 If master and specimen gratings both have spacing = 100 lines/in and the specimen grating is strained to 1% (e = 0.01), find fringe spacing. Due: 11/25 

11/20 
Optical Testing Calculations 




Lab 9  Continued 

14 
11/25 




11/27 
Thanksgiving Break 




Lab 10 –
Plate Frequencies 


15 
12/2 
Exam Review 



12/4 
Exam 2 




No Lab 


16 
12/9 
Bridge Evaluation 


12/11 
Bridge Evaluation 



No Lab 

Safety:
“As we begin this semester I
want to take a few minutes and discuss emergency preparedness. Purdue
University is a very safe campus and there is a low probability that a serious
incident will occur here at Purdue. However, just as we receive a “safety
briefing” each time we get on an aircraft, we want to emphasize our emergency
procedures for evacuation and shelter in place incidents. Our preparedness will
be critical if an unexpected event occurs.
Emergency preparedness is your personal
responsibility. Purdue University is continuously preparing for natural
disasters or humancaused incidents with the ultimate goal of maintaining a
safe and secure campus. Let’s review the following procedures:
·
There are nearly 300 Emergency Telephones
outdoors across campus and in parking garages that connect directly to the
Purdue Police Department (PUPD). If you feel threatened or need help, push the
button and you will be connected immediately.
·
If we hear a fire alarm, we will
immediately suspend class, evacuate the building, and proceed outdoors,
and away from the building. Do not use the elevator.
MET 311 EXAMINATIONS: Two exams are scheduled for the semester. Exams are open book, open notes and calculators are the only number crunching devices that may be used.
MET 311 HOMEWORK: Homework problems will be assigned at most class sessions. All problems will be graded. All assigned problems must be handed in at the end of the day on which they are due and will be graded on a tenpoint basis. Homework up to one week late will have a 20% penalty (20% of the possible number of points). Homework more than one week late will not be graded. Homework should be turned in at the drop box in Knoy Hall by 4:30 on the day it is due. I encourage students to work together on their homework if it helps them learn and if the work they turn in is their own. Test questions are patterned on homework questions. If you don’t really understand the homework solutions you’ve turned in, the tests are likely to be a problem for you.
MET 311 POLICIES AND PRACTICES:
ATTENDANCE: You are expected to attend in all lecture and laboratory sessions, including exam sessions. If a lab or exam absence is unavoidable, contact the instructor beforehand. Any unexcused missed lab session will result in a grade of zero for that lab. In all circumstances, you are responsible for learning the material covered during all class meetings. Safety glasses are required for all labs; bringing a thumb drive is recommended. Assuming extenuating circumstances do not apply, if you miss three lab sessions or fail to submit three reports within two weeks following their due dates, you will automatically fail the laboratory portion of the course.
REPORTS: Lab reports are due one week after the lab session, unless otherwise specified. Lab reports will be accepted up to one week after their respective due date, with a 5 point per day late penalty. Under extenuating circumstances, late penalties may be waived.
COMMUNICATION: Course communication is primarily electronic. Students will need to have a valid School of Technology career account to access the course website and materials. Check the course web site regularly for updates and notices. It will be updated regularly throughout the semester to include new sample problems, test answers keys and class administrative information. Some information will only be available during class meetings.
PARTICIPATION: You will learn more if you actively participate in all class and lab sessions, complete all assignments (reading, homework, and lab reports), and take responsibility for learning the course material. When you have questions, you need to pursue their answers. However, if, after a reasonable amount of effort, you are still struggling, come to my office. I can’t help if I don’t know you have a problem.
INTEGRITY and ETHICS: No student should take unfair advantage of another. All students are assumed to be acting honorably until they show otherwise. However, I won’t tolerate cheating in any form.
If you are not sure whether what you are doing is cheating, ask yourself whether it would make your mother proud of you if she knew about it. For a more formal description, refer to University Regulations, Part 5, Section III.B.2.a., regarding dishonesty.
Course Core
Learning Objectives:
1. Calculate principal stresses, maximum shear stress, and principal direction in a plane when given the loading condition.
2. Select the appropriate type of strain gage(s) for a given test specimen or component.
3. Determine the proper strain gage orientation for measurement of the strain induced by a single loading.
4. Calculate principal strains, maximum shearing strain, and principal direction on a surface from strain gage rosette data.
5. Convert strain values to stress values when given appropriate material information.
6. Manipulate strain gages in a simple Wheatstone Bridge circuit configuration to isolate and measure strain from one of several loadings.
7. Perform an openended experimental investigation in solid mechanics.