P h y s i c s   o f   S t r i n g s

Design and Inverse Problems

Spring 2006 VIGRE Seminars

Schedule, Notes, MATLAB, etc.

24 Mar 2006 Sean Hardesty's very helpful notes containing data for the inverse problem and comments on units.
21 Mar 2006 Sean Hardesty on damped strings
Assignment: Code up the inverse algorithm described in wav5.pdf and test with real data.
We will be discussing this in class on 28 March.
7 Mar 2006 Inverse eigenvalue problem for the beaded string.
Notes: wav4.pdf, wav5.pdf.
28 Feb 2006 Data from pluck of a string with 2,4 beads (zip file, 16.5 MB)
to be used for inverse spectral problems. Tension read 1.7 mV (~5.5 lbf).
Also, Jeff calibrated the force transducer. You can get a Matlab figure: pdf, fig.
16 Feb 2006 Lots of new data that Erin took with a nylon string (zip file, 20.28 MB) and up to two beads. Excellent agreement is shown in bead_exp.m, having used data to recalibrate the force transducer. The MATLAB scripts read .wav files (stored in the .zip file linked above) and produce the plots that are shown in the .pdf files.
9 Feb 2006 Data for pluck of a string with 3 beads used in 6 Feb class (wav file, 1.2 MB)
and a MATLAB script bead3a.m (built upon Sean's fftwave.m) for plotting.
6 Feb 2006 Data available from pluck of beaded string (wav file, 3.2 MB)
Data available from another pluck of beaded string (wav file, 2.9 MB)
4 Feb 2006 Data available from new pluck of Tony's guitar string (wav file, 1.0 MB) using the new electronics box. The noise seems to have largely gone away. It is easy to tell if you listen to the two files on a set of speakers with some bass - you can hear the hum at 120 Hz, almost exacly two octaves below the fundamental.
3 Feb 2006 Data available from pluck (1 Feb) of Tony's guitar string (wav file, 1.7 MB). If you're not familiar with Matlab's wavread function and the FFT, try this script. There is still noise coming from the power supply at multiples of 120 Hz. Sean aims to fix this over the weekend.
31 Jan 2006 Model of beaded string, fundamental and harmonic modes
Design and implementation of physical experiment with beaded string
- Reading: Gantmacher and Krein: pages 119-124
24 Jan 2006 Model of compound pendulum, fundamental and harmonic modes
- Reading: Gantmacher and Krein: pages 118-119, 127
- pendulum.m. A snapshot of the animation:

17 Jan 2006 Overview; description of experimental apparatus