the following are what i consider the main strengths of...
TRANSCRIPT
Comments from Derek Baker: The following are what I consider the main strengths of this presentation, some comments and an area in which I think it can be improved. Obviously since I am posting this as an example, I consider this to be a very good presentation and the Strengths far outweigh the Area for Improvement.
Strengths:
⋅ Most slides are very visual (graphic intensive rather than text intensive) with text used to support the graphics. During the presentation Kerim did a good job of expanding on the slide rather than just reading from the slide.
⋅ All major content is on a white (rather than textured or colored background) background, which makes reading the slide easier.
⋅ References are provided in a smaller font on the relevant slide, rather than summarizing the references on a separate slide at the end. This makes each slide self‐contained and portable.
⋅ Each slide has a slide number and total number of slides in the presentation to orient the listener. ⋅ The Outline is repeated several times throughout the presentation to help keep the reader orientated. ⋅ Clear statement of Thesis Objectives, a flow chart to complete the research (Thesis Guideline), and a
Timeline to Graduation. ⋅ The slide show ends with a slide summarizing the most important ideas that the audience should take
from the presentation and that helps to stimulate questions. Specifically, the last slide does not just say “Thank you” or similar.
⋅ The presentation lasted 25 minutes (the suggested time).
Comment:
⋅ At research conferences you will typically find that the most accomplished speakers tend to have very simple slide designs containing very sophisticated graphics developed through their research to communicate their results; in fact, some of the most accomplished speakers use a pure white slide. The least accomplished speakers tend to have very fancy slide designs but very poor graphics. While I normally do not like the PowerPoint slide formats offered by Microsoft, in this case I thought the water design that Kerim chose worked very well for several reasons. First and foremost, the audience was general Mechanical Engineering MS students working across a broad range of research topics; thus this water format helped to provide context for the presentation. Second, the background behind the main content was pure white, rather than textured or colored, which made reading the slide easier. If Kerim’s presentation was not about the design of a transducer for underwater acoustics, I do not think that this slide format would have been appropriate. Additionally, if Kerim was giving this presentation to a group of experts in the area, I am not sure the slide format would have been appropriate. But in this case, I think the slide format worked well. In summary, be careful when choosing a slide format, especially if it does not directly support your presentation.
Area for Improvement:
⋅ Kerim and I went through his presentation on my computer the day before the presentation, and everything looked great. Unfortunately, and as is often the case, the data projector for the presentation was not of a high quality and could not render some of the subtle colors properly. For example, some of the lighter colors were displayed as almost white (which means that could not be read) and the data project was not able to show good contrast between the waves on slide 21 (i.e., the waves were not visible). The result was Kerim had to say “You cannot see the waves on this slide, but…” and then describe what the audience was suppose to see. The problem of having slides look great on a computer but that cannot be read using a data projector is common and something that I have experienced on many occasions. The problem tends to be worse when content is put on top of a textured or colored background, which is why most people prefer a white background.
“DESIGN OF A TONPILZ-TYPE TRANSDUCER”
Kerim Çepni
December 24, 2010Department of Mechanical Engineering
Middle East Technical University
Thesis Supervisor: Dr. Derek K. Baker
Thesis Co-Supervisor: Dr. Mehmet Çalışkan
Outline
Introduction A Little History
Sonar Types & Some Applications
Piezoelectricity
Acoustic Waves
Overview of Tonpilz-Type Transducer
Transducer Modeling Main Types of Modeling
Completed Work: FEM
Thesis Guideline
Thesis Objectives
Timeline to Graduation
2 / 27
A Little History
Aristotle
Leonardo da Vinci
First quantitative experiment in 1826
3 / 27
Reference: Marvin Lasky, 1976, “Review of Undersea Acoustics to 1950,” JASA, 61(2), pp. 283-297.
A Little History (2)
Discovery of piezoelectricity in 1880
First patent about underwater echo ranging, a
month after the tragedy of Titanic in 1912
First underwater piezoelectric transducer in
1917
4 / 27
Reference: Charles H. Sherman, and John L. Butler, 2007, Transducers and Arrays for Underwater Sound, Springer, New York.
Sonar Types
Sonar: Sound Navigation and Ranging
Passive
Active
5 / 27
Reference: http://www.yourdictionary.com/images/science/ASsonar.jpg
Some Sonar Applications
Anti-submarine
Mine
Torpedo
Submarine Navigation
Sonobuoy
Communication
Fisheries
Side-scan
Tracking
Unmanned Underwater Vehicles
Security
6 / 27
Reference: Charles H. Sherman, and John L. Butler, 2007, Transducers and Arrays for Underwater Sound, Springer, New York.
7 / 27
Reference: Robert J. Urick, 1983, Principles of Underwater Sound, Peninsula Publishing, Los Alton, California.
Some Sonar Applications (2)
Piezoelectricity
Direct Piezoelectric Effect
Reverse Piezoelectric Effect
These effects are linear and reciprocal.
8 / 27
Electrical VoltagePressure
Electrical Field Strain
Reference: http://image.made-in-china.com/2f0j00IeCtQBfEOcpw/Piezoelectric-Ceramic-PZT4-PZT5-PZT8-.jpg
Acoustic Waves
Characteristics of Acoustic Waves
Frequency
Amplitude (Sound Pressure Level)
Waveform
9 / 27
Reference: http://www.fao.org/docrep/003/w0615e/W0615E02.HTM
Overview of Tonpilz
Sample 3D Views of Tonpilz
10 / 27
Main Components of Tonpilz
Overview of Tonpilz (2)
German word meaning “Singing Mushroom”
11 / 27
Overview of Tonpilz (3)
Main Performance Characteristics
Radiated Sound Pressure Level
Resonance Frequency
Bandwidth
12 / 27
Outline
Introduction A Little History
Sonar Types & Some Applications
Piezoelectricity
Acoustic Waves
Overview of Tonpilz-Type Transducer
Transducer Modeling Main Types of Modeling
Completed Work: FEM
Thesis Guideline
Thesis Objectives
Timeline to Graduation
13 / 27
Main Types of Models
Equivalent Circuit (Lumped) Models
Distributed (Transmission Line) Models
Matrix Models
Finite Element Models
14 / 27
Equivalent Circuit (Lumped) Models15 / 27
References: http://upload.wikimedia.org/wikipedia/commons/4/4a/Mass-Spring-Damper.png
http://upload.wikimedia.org/wikipedia/commons/4/4e/RLC_series_circuit.png
Mechanical Electrical
Mass
Damping
Stiffness
Velocity
Force
Inductance
Resistance
Capacitance-1
Current
Voltage
Distributed (Transmission Line) Models
A Sample Distributed Model:
16 / 27
Reference: Duo Teng , Hang Chen, Ning Zhu, Guolei Zhu, Yanni Gou, 1976, “Comparison About Design Methods of Tonpilz
Type Transducer,” Global Design to Gain a Competitive, Chapter 1, pp. 81-89.
Mason’s Equivalent Circuit of Tonpilz
Matrix Models17 / 27
Model of a Sample TransducerPiezoceramic Ring as a 5-access
Network
Reference: M.D. Radmanovic, D.D. Mancic, 2004, Designing and Modeling of The Power Ultrasonic Transducers, University
of Nis, MPI, Switzerland.
Finite Element Models18 / 27
Axisymmetric FEM of a Sample Transducer
Reference: Charles H. Sherman, and John L. Butler, 2007, Transducers and Arrays for Underwater Sound, Springer, New York.
Finite Element Model19 / 27
Geometry & Electrodes Mesh
Finite Element Model (2)20 / 27
Mesh with Fluid Medium
Finite Element Model (3)21 / 27
Pressure Distribution at 27kHz [Pa]Pressure Distribution at 36.5kHz (Resonance Frequency) [Pa]
Finite Element Model (4)
Sound Pressure Level with 1V Driving Voltage at 1m Distance
22 / 27
Frequency [Hz]
SPL
[dB]
Finite Element Model (5)
Sound Pressure Level with 1V Driving Voltage at 1m Distance
23 / 27
Frequency [Hz]
SPL
[dB]
Outline
Introduction A Little History
Sonar Types & Some Applications
Piezoelectricity
Acoustic Waves
Overview of Tonpilz-Type Transducer
Transducer Modeling Main Types of Modeling
Completed Work: FEM
Thesis Objectives
Thesis Guideline
Timeline to Graduation
24 / 27
Thesis Objectives25 / 27
Design, Manufacturing and Evaluation of a Tonpilz-
Type Piezoelectric Transducer
Comparison of Experimental Results with Modeling
Results
Comparison of Two Design Procedures Involving
Different Modeling Techniques (Matrix Method vs. FEM)
Thesis Guideline26 / 27
Design Criteria & Constraints
Lumped Model
Rough Dimensions
FEMMatrix Model
Optimization
Optimal
Dimensions
Optimal
Dimensions
Optimization
Comparison
Fixed Piezoceramic Rings
Design Criteria & Constraints
Lumped Model
Rough Dimensions
FEM
Optimal Dimensions
Optimization
Realization
Experiment
Comparison with Model Results
Questions, suggestions?27 / 27
Timeline to Graduation