Comments from Derek Baker: Strengths: Comment: Area for Improvement:

Transcription

1 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: Comment: 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). 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.

2 DESIGN OF A TONPILZ-TYPE TRANSDUCER Kerim Çepni Thesis Supervisor: Dr. Derek K. Baker Thesis Co-Supervisor: Dr. Mehmet Çalışkan December 24, 2010 Department of Mechanical Engineering Middle East Technical University

3 Outline 2 / 27 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

4 A Little History 3 / 27 Aristotle Leonardo da Vinci First quantitative experiment in 1826 Reference: Marvin Lasky, 1976, Review of Undersea Acoustics to 1950, JASA, 61(2), pp

5 A Little History (2) 4 / 27 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 Reference: Charles H. Sherman, and John L. Butler, 2007, Transducers and Arrays for Underwater Sound, Springer, New York.

6 Sonar Types 5 / 27 Sonar: Sound Navigation and Ranging Passive Active Reference:

7 Some Sonar Applications 6 / 27 Anti-submarine Mine Torpedo Submarine Navigation Sonobuoy Communication Fisheries Side-scan Tracking Unmanned Underwater Vehicles Security Reference: Charles H. Sherman, and John L. Butler, 2007, Transducers and Arrays for Underwater Sound, Springer, New York.

8 Some Sonar Applications (2) 7 / 27 Reference: Robert J. Urick, 1983, Principles of Underwater Sound, Peninsula Publishing, Los Alton, California.

9 Piezoelectricity 8 / 27 Direct Piezoelectric Effect Pressure Electrical Voltage Reverse Piezoelectric Effect Electrical Field Strain These effects are linear and reciprocal. Reference:

10 Acoustic Waves 9 / 27 Characteristics of Acoustic Waves Frequency Amplitude (Sound Pressure Level) Waveform Reference:

11 Overview of Tonpilz 10 / 27 Sample Main Components 3D Views of Tonpilz

12 Overview of Tonpilz (2) 11 / 27 German word meaning Singing Mushroom

13 Overview of Tonpilz (3) 12 / 27 Main Performance Characteristics Radiated Sound Pressure Level Resonance Frequency Bandwidth

14 Outline 13 / 27 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

15 Main Types of Models 14 / 27 Equivalent Circuit (Lumped) Models Distributed (Transmission Line) Models Matrix Models Finite Element Models

16 Equivalent Circuit (Lumped) Models 15 / 27 Mechanical Electrical Mass Damping Stiffness Velocity Force Inductance Resistance Capacitance -1 Current Voltage References:

17 Distributed (Transmission Line) Models 16 / 27 A Sample Distributed Model: Mason s Equivalent Circuit of Tonpilz 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

18 Matrix Models 17 / 27 Piezoceramic Ring as a 5-access Network Model of a Sample Transducer Reference: M.D. Radmanovic, D.D. Mancic, 2004, Designing and Modeling of The Power Ultrasonic Transducers, University of Nis, MPI, Switzerland.

19 Finite Element Models 18 / 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.

20 Finite Element Model 19 / 27 Geometry & Electrodes Mesh

21 Finite Element Model (2) 20 / 27 Mesh with Fluid Medium

22 Finite Element Model (3) 21 / 27 Pressure Distribution Pressure Distribution at 36.5kHz at (Resonance 27kHz [Pa] Frequency) [Pa]

23 Finite Element Model (4) 22 / 27 Sound Pressure Level with 1V Driving Voltage at 1m Distance SPL [db] Frequency [Hz]

24 Finite Element Model (5) 23 / 27 Sound Pressure Level with 1V Driving Voltage at 1m Distance SPL [db] Frequency [Hz]

25 Outline 24 / 27 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

26 Thesis Objectives 25 / 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)

27 Thesis Guideline 26 / 27 Design Criteria & Constraints Matrix Model Optimization Optimal Dimensions Lumped Model Rough Dimensions Comparison FEM Optimization Optimal Dimensions Fixed Piezoceramic Rings Design Criteria & Constraints Lumped Model Rough Dimensions FEM Optimization Optimal Dimensions Realization Experiment Comparison with Model Results

28 Questions, suggestions? 27 / 27 Timeline to Graduation