About

Amanda Hanford is an Assistant Research Professor affiliated with the Acoustics program at Penn State University. She is associated with the Applied Research Laboratory, the Mechanical Engineering department, and the Center for Acoustics and Vibration. Her contact information includes her email ald227@psu.edu and phone number 814-865-4528. Her research focuses on acoustics within an interdisciplinary framework, contributing to Penn State's renowned Graduate Program in Acoustics, which offers degrees such as the Master of Engineering in Acoustics, Master of Science in Acoustics, and Doctor of Philosophy in Acoustics. The program, established in 1965, is recognized as a leading resource for graduate education in acoustics in the United States.

Research topics

• Computer Science
• Optics
• Acoustics
• Physics
• Materials science
• Optoelectronics
• Telecommunications

Selected publications

• Modeling a tunable plate in a leaky wave antenna

  The Journal of the Acoustical Society of America · 2025-12-01 · 1 citations

  articleSenior author

  An acoustic leaky-wave metamaterial is an array of cells comprised of ducts and plates and is used for beam steering. The phase interactions caused by the combination of ducts and plates can result in effective material properties not found in natural materials. Natural materials and metamaterials without plates can steer the output radiation lobe in a limited range of 90°, whereas leaky-wave metamaterials can steer in a full range of 180°. This metamaterial is typically passive and has a narrow frequency bandwidth. It can also be difficult to avoid a directivity discontinuity in the center of the bandwidth if there are manufacturing errors, material flaws, or design miscalculations. By adding tunable diaphragms between the unit cells, it is theoretically possible to design a metamaterial that can shift the bandwidth by changing the magnitude of the tunable mass density or tunable bulk modulus. This article shows a computational model for a tunable leaky-wave antenna and predicts how incorporating a piezoelectric diaphragm affects the output of the system.

  PublisherDOI

• Using a leaky-wave antenna as an acoustic prism for speech-separation

  The Journal of the Acoustical Society of America · 2024

  Senior authorCorresponding
  • Computer Science
  • Acoustics
  • Computer Science

  Leaky-wave antennas (LWA) are an acoustic metamaterial comprised of an array of unit cells. For a 1D line array, the output ranges from 0° to 180° relative to the direction of the axis of the array. The direction of the output is dependent on the frequency of the input; a single frequency input will produce a highly directive output beam at a specific angle. Much like an optic prism, which can be used to split a complex optic wave into its components, a LWA can be used to split a complex input audio wave into its components. This work explores the capabilities of LWA to separate transient signals like human speech into different output directions. This is accomplished by way of an equivalent circuit model of the LWA that enables simulations in both the time and frequency domains. The frequency domain performance of the model is validated against previously published results, and then the transient response is shown to recover these as well once steady-state is reached

  PublisherDOI

• Data and information management for acoustics research

  The Journal of the Acoustical Society of America · 2024-03-01 · 1 citations

  article1st authorCorresponding

  A critical part of verification and validation in academic research includes the important consideration of data and information management. As researchers grapple with escalating volumes of data, effective data management becomes imperative for optimizing operational processes and ensuring reproducibility and archivability. Data management involves the organization, storage, and retrieval of information to support research advancements and strengthen the foundation of decision making and scientific knowledge. Key components also include data operations, which involves the orchestration of data workflows, and data quality management, which focuses on maintaining accurate and reliable data. This talk explores the multifaceted aspects of data management, emphasizing its significance in ensuring data quality, accuracy and accessibility.

  PublisherDOI

• Effects of Foil Camber and Non-Zero Angle of Attack on The Unsteady Forces Produced by a Turbomachine Ingesting Turbulence

  2023-10-29

  article

  Abstract Turbomachinery rotor blades experience unsteady lift forces due to turbulence and circumferential variation in the inflow velocity. These forces can be a source of unwanted vibration and radiated sound. The unsteady force spectrum is often modelled to first order using a flat plate approach. However, it is known that mean loading effects can have a significant influence on airfoil unsteady lift for sinusoidal gusts with certain wavevector orientations [1]. To this end, the Atassi [1] gust response model for airfoils with camber and non-zero angle of attack has been incorporated into a rotor turbulence ingestion model [2] to determine the effect on the unsteady force spectrum. The Atassi gust model describes the interaction between a two-dimensional sinusoidal gust with a cambered foil placed at a small angle of attack to the mean flow. To apply this single harmonic gust response to the turbulence ingestion model, the gust responses for sinusoidal components with a distribution of wavevector angles are integrated based on an isotropic turbulence energy spectrum. The updated turbulence ingestion model is then applied to a parametric study investigating the effects of foil geometry (specifically camber and non-zero angle of attack) on the unsteady forces produced from turbulence ingestion. The baseline geometry used for this study is the Sevik [3] rotor. To assess the sensitivity of the unsteady force spectrum to camber, predictions for a 0, 6, and 12% cambered foil with zero thickness at 0° angle of attack are generated. For these cases, foil camber effects are found to be largely negligible, except at low frequencies where the additional forces generated by streamwise gust components become dominant. The influence of non-zero angle of attack on the turbulence ingestion rotor force is also relatively minor for small angles of attack, but an increase of a few dB is predicted at higher frequencies as the angle of attack is increased to 15°. These results are generally consistent with measurements reported in the literature, where camber and angle of attack effects are shown to be weak, and the overall effects are much smaller than the changes in the sinusoidal gust responses due to the streamwise symmetry and averaging effect that occurs with isotropic turbulence. While the turbulence ingestion model was successfully extended to account for foil geometry effects using the Atassi gust response model, there is continued interest to explore the effects on the unsteady force spectrum when the simplifying assumption of isotropic turbulence is removed.

  PublisherDOI

• Increased modal damping of undamped single and multiscale acoustic black hole panels

  JASA Express Letters · 2023-11-01

  articleOpen accessSenior authorCorresponding

  The acoustic black hole (ABH) effect has been shown to increase damping of structures by focusing energy into a tapered-thickness region with added damping material. This paper illustrates that enhanced damping can be achieved without the use of damping material. Three panels were designed with different ABH grid patterns and parameters and compared to a baseline panel. Increased damping is shown to exist for two of the three ABH panels even though no damping material was applied. The panel modes which exhibited increased damping were local to the ABH grid while global modes did not exhibit increased damping.

  PublisherOA PDFDOI

• Exploration of tunable properties of a one-dimensional leaky-wave antenna

  The Journal of the Acoustical Society of America · 2022

  Senior authorCorresponding
  • Computer Science
  • Acoustics
  • Computer Science

  Leaky-wave antennas (LWA) are commonly used in beam-steering situations such as radars, imaging, and other such frequency scanning applications. LWA are particularly useful metamaterials due to their relatively simple structure of repeated cells in a linear array and their broad scanning range allowing for more use to come from a single frequency sweep. Among current methods to model and design acoustic LWA are notably high fidelity models such as finite element analysis and low fidelity models such as the acoustic transmission-line equations. Presented is a technique for a mid-fidelity model of a one-dimensional acoustic LWA using a lumped element system. This model is used to explore rapid evaluations of different tuning options in the elastic membranes separating the unit cells of the structure. Comparisons are made between time and frequency domains as well as modal and physical space simulations.

  PublisherDOI

• Discussion of a leaky-wave metamaterial design and the effects of membrane thickness on the dispersion direction

  Proceedings of meetings on acoustics · 2022 · 1 citations

  Senior authorCorresponding
  • Materials science
  • Optics
  • Acoustics
  PublisherDOI

• Evaluation of metamaterial unit cell analysis techniques

  The Journal of the Acoustical Society of America · 2019-03-01

  article1st authorCorresponding

  The field of acoustic metamaterials has produced novel materials in a wide variety of applications. An important step in designing a metamaterial is unit cell analysis with subwavelength geometry. There are several techniques used for unit cell analysis when designing acoustic properties of interest for metamaterial applications. Such techniques include, but are not limited to, band diagrams, effective material properties, or half-space homogenization. This talk discusses the challenges and tradeoffs between analysis techniques and types of structures that lend to one method or another. Unit cell analysis methods will be evaluated to perform trade space exploration, including validation and parametric studies for metamaterial design.

  PublisherDOI

• Comparison measurements of homogenized material properties of underwater acoustic metamaterials

  The Journal of the Acoustical Society of America · 2019-10-01

  articleSenior author

  A current area of research interest in acoustic metamaterials is the experimental validation of the effective properties computed using analytical and numerical models. This is generally done through an inverse measurement technique, by measuring the reflective and transmitted wave amplitudes and phases to calculate an effective impedance. When the background fluid used for this measurement is air, either an impedance tube or anechoic chamber can be utilized for these measurements. However, if the application of the metamaterial is for in-water applications, the measurement of these properties becomes much more difficult due to many complicating factors. Therefore, there has been little work obtaining homogenized, anisotropic material properties of underwater acoustic metamaterials. In this work, we present comparison of measurement methods of an acoustic metamaterial in an aqueous environment: a water-filled impedance tube and in a reverberant water tank. The metamaterial response will be predicted, and compared to the measurement in the impedance tube and reverberant tank. Additionally, trade-offs between the two experimental methods will be given.

  PublisherDOI

• Development of a perforated plate underwater acoustic ground cloak

  The Journal of the Acoustical Society of America · 2019-10-01 · 15 citations

  article

  One of the commonly investigated transformation acoustic device is the ground cloak, which conceals a scattering object on a reflecting surface. Multiple studies have numerically simulated acoustic ground cloaks, but because of the challenges associated with realizing a homogeneous anisotropic metamaterial, only two acoustic ground cloaks have been built and tested. Perforated plastic plates in air were used to construct two and three dimensional ground cloaks and alternating layers of brass and water were used to construct an extended area ground cloak underwater. With underwater mass density anisotropy previously demonstrated for perforated steel plates, the primary focus of this article is to build and evaluate an underwater ground cloak with perforated steel plates. The cloak was evaluated at a water-air pressure release reflecting surface. The cloak successfully concealed the scattering object over a broad frequency range of 7-12 kHz.

  PublisherDOI

Frequent coauthors

• Micah R. Shepherd

  Brigham Young University

  11 shared

• Dean E. Capone

  Pennsylvania State University

  10 shared

• Peter Kerrian

  ATA Engineering (United States)

  9 shared

• Benjamin S. Beck

  7 shared

• Andrew S. Wixom

  Pennsylvania State University

  7 shared

• Lyle N. Long

  6 shared

• Kent L. Gee

  Brigham Young University

  5 shared

• Peter L. Tyack

  University of St Andrews

  4 shared