scholarly journals Discussion: “Pulse Propagation in Straight and Curved Beams—Theory and Experiment” (Crowley, III, F. B., Phillips, J. W., and Taylor, C. E., 1974, ASME J. Appl. Mech., 41, pp. 71–73)

1974 ◽  
Vol 41 (3) ◽  
pp. 836-836
Author(s):  
W. Goldsmith
Keyword(s):  
Pulse Propagation ◽  
Curved Beams ◽  
Theory And Experiment

Pulse Propagation in Straight and Curved Beams—Theory and Experiment

1974 ◽  
Vol 41 (1) ◽  
pp. 71-76 ◽  
Author(s):  
F. B. Crowley ◽  
J. W. Phillips ◽  
C. E. Taylor
Keyword(s):  
Method Of Characteristics ◽  
Pulse Propagation ◽  
Curved Beam ◽  
Curved Beams ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Isochromatic Fringe ◽  
Fringe Patterns ◽  
Theory And Experiment ◽  
Good Agreement

The equations from Morley’s one-dimensional theory governing the motion of a curved beam subjected to an arbitrary pulse are solved numerically using the method of characteristics. Propagation of initially longitudinal pulses in beam assemblages with both straight and curved sections is investigated. Simulated isochromatic fringe patterns are constructed by a Calcomp plotter and are compared with actual photoelastic patterns. Remarkably good agreement is found between theory and experiment in all the cases investigated. It is concluded that Morley’s theory can be applied to pulse propagation problems of the type investigated.

scholarly journals Pulse Propagation in a Helix—Theory and Experiment

1974 ◽  
Vol 41 (4) ◽  
pp. 1047-1051 ◽  
Author(s):  
J. W. Phillips
Keyword(s):  
Experimental Model ◽  
Strain Gage ◽  
Method Of Characteristics ◽  
Pulse Propagation ◽  
Numerical Results ◽  
Interface Problem ◽  
One Dimensional ◽  
The Method Of Characteristics ◽  
Theory And Experiment

Wittrick’s general one-dimensional equations governing the propagation of small elastic disturbances in a helical waveguide are solved by the method of characteristics, and numerical results for a particular interface problem are compared with strain gage records from an impacted experimental model. The agreement between theory and experiment is found to be excellent for the type of pulse considered, namely, an initially longitudinal compressive pulse approximately seventy rod-diameters in length.

scholarly journals Longitudinal Strain Pulse Propagation in Wide Rectangular Bars: Part 2—Experimental Observations and Comparisons With Theory

1963 ◽  
Vol 30 (1) ◽  
pp. 61-69 ◽  
Author(s):  
O. E. Jones ◽  
A. T. Ellis
Keyword(s):  
Plane Stress ◽  
Pulse Propagation ◽  
Step Function ◽  
Pressure Loading ◽  
Stress Theory ◽  
Second Mode ◽  
Fringe Patterns ◽  
Strain Pulse ◽  
Thickness Mode ◽  
Theory And Experiment

The plane-stress theory presented in Part 1 is shown to predict qualitatively the warping of plane sections observed in transient fringe patterns obtained using birefringent coatings and in dynamic photoelastic pictures obtained in other investigations. Measurements using conventional techniques are described in which wide rectangular bars were subjected to a longitudinal step-function pressure loading produced by a shock tube. Comparisons show that the gross features of the experimental records for the head of the pulse are qualitatively predicted by the theory. Both theory and experiment show that short-wavelength, second-mode disturbances arrive very early. Experimentally it is observed that these disturbances are accomplished by thickness-mode activity which cannot be accounted for by the plane-stress theory.

On the theory of pulse propagation in curved beams

1972 ◽  
Vol 24 (2) ◽  
pp. 247-258 ◽  
Author(s):  
J.W. Phillips ◽  
F.B. Crowley
Keyword(s):  
Pulse Propagation ◽  
Curved Beams

Electrostatic optics and aberration correction in the 1940s and today

1992 ◽  
Vol 50 (1) ◽  
pp. 6-7
Author(s):  
Gertrude F. Rempfer
Keyword(s):  
Electron Microscope ◽  
Focal Point ◽  
Focal Length ◽  
High Vacuum ◽  
Electron Optics ◽  
Applied Physics ◽  
Electrostatic Lenses ◽  
Commercial Instrument ◽  
The University ◽  
Theory And Experiment

I became involved in electron optics in early 1945, when my husband Robert and I were hired by the Farrand Optical Company. My husband had a mathematics Ph.D.; my degree was in physics. My main responsibilities were connected with the development of an electrostatic electron microscope. Fortunately, my thesis research on thermionic and field emission, in the late 1930s under the direction of Professor Joseph E. Henderson at the University of Washington, provided a foundation for dealing with electron beams, high vacuum, and high voltage.At the Farrand Company my co-workers and I used an electron-optical bench to carry out an extensive series of tests on three-electrode electrostatic lenses, as a function of geometrical and voltage parameters. Our studies enabled us to select optimum designs for the lenses in the electron microscope. We early on discovered that, in general, electron lenses are not “thin” lenses, and that aberrations of focal point and aberrations of focal length are not the same. I found electron optics to be an intriguing blend of theory and experiment. A laboratory version of the electron microscope was built and tested, and a report was given at the December 1947 EMSA meeting. The micrograph in fig. 1 is one of several which were presented at the meeting. This micrograph also appeared on the cover of the January 1949 issue of Journal of Applied Physics. These were exciting times in electron microscopy; it seemed that almost everything that happened was new. Our opportunities to publish were limited to patents because Mr. Farrand envisaged a commercial instrument. Regrettably, a commercial version of our laboratory microscope was not produced.

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