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
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.