Upcoming Events
November 30
Noon – 1:00 p.m. (ET) | 201 Applied Science Building and Zoom
Blind Defect Inspection of Silicon using High Frequency Focused Shear Ultrasound, Lauren Katch
Determining the Bounds of the Frequency Stop-Bandgap in Elastodynamic Metasurfaces for S0 Lamb Wave Excitation, Jeremy Keirn
Blind Defect Inspection of Silicon using High Frequency Focused Shear Ultrasound
Abstract: Defect inspection in silicon wafers becomes increasingly challenging as semiconductor parts decrease in size. Inspection during manufacturing is especially motivated by the recent $50 billion investment in American semiconductor manufacturing through the CHIPS and Science Act of 2022. High frequency normal incidence ultrasound has shown promise in detecting micron sized defects, but the technique is not sensitive to vertically oriented defects like back surface breaking cracks. Altering the setup to an oblique inspection orientation using shear waves has shown promise for detecting known cracks. However, the crack scattering behavior becomes directionally dependent because of silicon’s anisotropy. Therefore, sizing techniques and focusing calibration need to be adjusted for this directionality. Within this work, the sensitivity to detecting cracks at various orientations is explored.
Bio: Lauren Katch received her bachelor degrees in mechanical engineering and engineering science from Penn State in 2020. She then continued directly into a doctoral program within the engineering science and mechanics department, where she has worked on ultrasonics research under the guidance of Dr. Andrea Argüelles. As part of the Argüelles Research Group, Lauren has explored a range of topics from defect detection in silicon wafers to phononic crystal modeling.
Determining the Bounds of the Frequency Stop-Bandgap in Elastodynamic Metasurfaces for S0 Lamb Wave Excitation
Abstratct: It has been shown that metasurfaces, a 2D version of a metamaterial, can be used to create a stop-bandgap for the S0 Lamb wave mode. This type of control of Lamb waves is achieved by tuning resonator designs to apply an appropriate boundary condition at their base when attached to a plate that is made from the same material. Recent studies for surface waves in bulk media have shown that there is a possible connection between the width of the bandgap and the resonances and anti-resonances in the frequency response function of the resonators. This study attempts to show that a similar connection exists for metasurfaces and the associated Lamb wave modes. Using a combination of simulations from COMSOL Multiphysics 6.0 and 6.1 and experiments on a 1 mm aluminum plate, it is shown that the width of the bandgap is bounded at the resonances and anti-resonances of the resonators. With this understanding of the limits of the bandgap, an optimization process can be used to generate resonator geometries that separate the resonances, which results in an increase in the width of the bandgap.
Bio: Jeremy Keirn is a master’s student majoring in Engineering Science and Mechanics with a minor in acoustics at Penn State. He has a bachelor of science in engineering science with minors in engineering mechanics and music Technology from Penn State. His primary research focus is numerical modelling of elastodynamic metasurfaces, which is part of a project directed by Dr. Parisa Shokouhi and Dr. Clifford Lissenden and funded by the National Science Foundation. He has also worked on a variety of other projects ranging from signal modelling of reverberations to testing of shear couplant mixtures.
November 3
Join via Zoom (Meeting ID: 938 5143 0854 | Password: 2023)
Title: Noise Estimation Framework for Advanced Air Mobility
Speaker: Joseph Czech, Principal Consultant, Harris Miller Miller & Hanson Inc.
Abstract: Community acceptance and adoption has been identified as a critical and challenging component as we prepare our communities for Advanced Air Mobility (AAM) operations. Although AAM vehicles may be significantly quieter than traditional rotorcraft, the proposed scale of operations and proximity to the built environment makes noise generated from AAM operations a concerning element. Therefore, it is essential to incorporate noise estimation in the planning stage. The presented analysis demonstrates a noise estimation framework for AAM operations. The framework utilizes simulation models and the current state of knowledge combined with laboratory data to inform the modeled sound sources. This framework is part of the Advanced Air Mobility – Community Integration Planning Tool. The noise estimation framework takes trajectories of proposed AAM operations and simulates them with the Advanced Acoustic Model to compute their noise exposure. Combined with demographics, the results can assess the potential for noise impact of the proposed operations. The framework is developed to provide quick and credible noise results with the ability to vary temporal and spatial granularity while accommodating different types of vehicles. The paper involves proposed multiple AAM cargo operations in the Midwest region of the United States.
Bio: Joseph Czech is a principal consultant at Harris Miller Miller & Hanson Inc. (HMMH) since 2016 and has more than 34 years in the acoustical consulting field, with experience conducting noise and/or environmental studies ranging in value from less than $10k up to $12M for a variety of military and civilian clients. His expertise is in modeling aircraft noise, measurement, project management, research, public meetings, and litigation support. Czech is an expert in the use of the NOISEMAP suite (including MR_NMAP and the Advanced Acoustics Model) and helped develop AEDT. Besides subsonic aircraft, his projects have addressed the noise from road traffic (TNM), construction, blast/ordnance (BNOISE2), small arms (SARNM), (low- and high-speed rail, light rail, busway, electrical substations, and sonic booms.
October 25
SEMINAR CANCELED, will reschedule for spring 2024
Seminar Topic: New Practical Approaches for Modern PHM
Speaker: Jacob Bortman
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