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Articles 1 - 6 of 6
Full-Text Articles in Physics
Extracting Vibration Characteristics Of A Guitar Using Finite Element, Modal Analysis, And Digital Image Correlation Techniques, Kiran Patil, Javad Baqersad, Daniel Ludwigsen, Yaomin Dong
Extracting Vibration Characteristics Of A Guitar Using Finite Element, Modal Analysis, And Digital Image Correlation Techniques, Kiran Patil, Javad Baqersad, Daniel Ludwigsen, Yaomin Dong
Daniel Ludwigsen
The sound quality generated by the guitar depends on the vibration characteristics (i.e. natural frequencies and mode shapes) of this instrument. Thus, it is of particular interest to the guitar manufacturers to be able to obtain global information about the characteristics of the guitar. Traditional sensors can only measure at discrete locations. However, digital image correlation (DIC) can measure full-field data on the surface of the structure. In the current paper, a finite element (FE) model of a guitar with free boundary configurations was developed using quadratic solid elements. An eigensolution was performed on the FE model to determine its …
Vector Acoustic Intensity Around A Tuning Fork, Daniel A. Russell, Justin Junell, Daniel O. Ludwigsen
Vector Acoustic Intensity Around A Tuning Fork, Daniel A. Russell, Justin Junell, Daniel O. Ludwigsen
Daniel Ludwigsen
The acoustic intensity vector field around a tuning fork is investigated. Theory for a longitudinal quadrupole source predicts a well-defined transition between near-field and far-field, with significant circulation of sound energy in the near-field. Vector components of the time-averaged intensity were measured using a two-microphone intensity probe and found to agree well with predictions from theory. The vector intensity map is interpreted, and shown to provide useful information about the near-field of an acoustic source.
A Simple Electric Field Probe In A Gauss's Law Laboratory, Daniel O. Ludwigsen, Gregory N. Hassold
A Simple Electric Field Probe In A Gauss's Law Laboratory, Daniel O. Ludwigsen, Gregory N. Hassold
Daniel Ludwigsen
Early in our calculus-based introductory course, students are introduced to electric fields and sometimes struggle with the abstraction of a vector field. They have less familiarity with the phenomena associated with electric fields, and the connection between phenomena and mathematical formalism is weaker. Our very next topic is Gauss's law.
Better Understanding Of Resonance Through Modeling And Visualization, Daniel O. Ludwigsen, Cayla Jewett, Matthew Jusczcyk
Better Understanding Of Resonance Through Modeling And Visualization, Daniel O. Ludwigsen, Cayla Jewett, Matthew Jusczcyk
Daniel Ludwigsen
Students encounter cavity resonance and waveguide phenomena in acoustics courses and texts, where the study is usually limited to cases with simple geometries: parallelepipeds, cylinders, and spheres. Long-wavelength approximations help with situations of more complexity, as in the classic Helmholtz resonator. At Kettering University, we are beginning to employ finite element modeling in our acoustics classes to help undergraduates better understand the acoustic modes of actual structures. This approach to the time-independent wave equation (the Helmholtz equation) was first used in a research and measurements class to investigate two classic resonance problems. The first problem was a study of resonance …
Choose Wisely: Static Or Kinetic Friction—The Power Of Dimensionless Plots, Daniel O. Ludwigsen, Kathryn A. Svinarich
Choose Wisely: Static Or Kinetic Friction—The Power Of Dimensionless Plots, Daniel O. Ludwigsen, Kathryn A. Svinarich
Daniel Ludwigsen
Consider a problem of sliding blocks, one stacked atop the other, resting on a friction-less table. If the bottom block is pulled horizontally, nature makes a choice: if the applied force is small, static friction between the blocks accelerates the blocks together, but with a large force the blocks slide apart. In that case, kinetic friction still forces the upper block forward but with less acceleration than the lower block. The choice, then, lies in the relative terms—what is meant by small and large? After a confusing experience during a recent exam, we’ve found a demonstration and graphical presentation that …
Acoustic Testing And Modeling: An Advanced Undergraduate Laboratory, Daniel A. Russell, Daniel O. Ludwigsen
Acoustic Testing And Modeling: An Advanced Undergraduate Laboratory, Daniel A. Russell, Daniel O. Ludwigsen
Daniel Ludwigsen
This paper describes an advanced laboratory course in acoustics, specifically targeted for students with an interest in engineering applications at a school with a strongly integrated industrial co-op program. The laboratory course is developed around a three-pronged approach to problem solving that combines and integrates theoretical models, computational models, and experimental data. The course is structured around modules that begin with fundamental concepts and build laboratory skills and expand the knowledge base toward a final project. Students keep a detailed laboratory notebook, write research papers in teams, and must pass laboratory certification exams. This paper describes the course layout and …