Title of Oral/Poster Presentation

Resonant Response of Flat Plates at High Temperatures

Class

Article

Graduation Year

2017

College

College of Engineering

Department

Mechanical and Aerospace Engineering Department

Faculty Mentor

Dr. Ryan Berke

Presentation Type

Oral Presentation

Abstract

During spacecraft reentry and hypersonic flight, materials are subjected to both high temperatures and vibrational loads. Flat plates have been shown to exhibit altered resonant responses while subjected to coupled thermo-acoustic loading otherwise not seen at room temperature. These resonant modes affect the structural stability of the material and can cause premature failure due to increased fatigue. The effect of elevated temperature in relation to vibrational resonance is relatively unknown and there is a lack of experimental data to support the commercially available numerical simulations.

The purpose of this study is to develop a model for the effect that increasing temperatures have on the resonant frequency of thin plates subjected to vibrational loading. Experiments are conducted on five flat plate samples of Hastelloy-X, a nickel-based superalloy, with aspect ratios of 1:1, 1.25:1, 1.5:1, 1.75:1, and 2:1. Samples are subjected to a sinusoidal load oscillating at frequencies ranging from 50 to 1000 Hz through which the samples experience approximately 8 resonant modes. These experiments are conducted on the sample both at room temperature and while subjected to multiple temperature gradients. Thermal loads are applied to the sample plates using magnetic induction via a pancake coil. A model is created using data obtained via three methods: (1) high speed measurements of the samples frequency response function (FRF) collected using a laser vibrometer and accelerometer; (2) full field measurements of the modal shape using stereo digital image correlation (DIC); and (3) full field measurements of the sample’s unique temperature profile using an infrared camera. These data collection methods allow accurate measurements without coming into contact with the sample or altering the resonant response. The results from this study can be used to determine possible inconsistencies between full-field experimental measurements and the commercially available numerical simulations.

Location

Room 154

Start Date

4-13-2017 3:00 PM

End Date

4-13-2017 4:15 PM

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Apr 13th, 3:00 PM Apr 13th, 4:15 PM

Resonant Response of Flat Plates at High Temperatures

Room 154

During spacecraft reentry and hypersonic flight, materials are subjected to both high temperatures and vibrational loads. Flat plates have been shown to exhibit altered resonant responses while subjected to coupled thermo-acoustic loading otherwise not seen at room temperature. These resonant modes affect the structural stability of the material and can cause premature failure due to increased fatigue. The effect of elevated temperature in relation to vibrational resonance is relatively unknown and there is a lack of experimental data to support the commercially available numerical simulations.

The purpose of this study is to develop a model for the effect that increasing temperatures have on the resonant frequency of thin plates subjected to vibrational loading. Experiments are conducted on five flat plate samples of Hastelloy-X, a nickel-based superalloy, with aspect ratios of 1:1, 1.25:1, 1.5:1, 1.75:1, and 2:1. Samples are subjected to a sinusoidal load oscillating at frequencies ranging from 50 to 1000 Hz through which the samples experience approximately 8 resonant modes. These experiments are conducted on the sample both at room temperature and while subjected to multiple temperature gradients. Thermal loads are applied to the sample plates using magnetic induction via a pancake coil. A model is created using data obtained via three methods: (1) high speed measurements of the samples frequency response function (FRF) collected using a laser vibrometer and accelerometer; (2) full field measurements of the modal shape using stereo digital image correlation (DIC); and (3) full field measurements of the sample’s unique temperature profile using an infrared camera. These data collection methods allow accurate measurements without coming into contact with the sample or altering the resonant response. The results from this study can be used to determine possible inconsistencies between full-field experimental measurements and the commercially available numerical simulations.