2023_programme: Inverse estimation of pressure- and shear wave speeds from scattering experiments from spherical samples
- Session: 18. Underwater acoustic calibration and standards
Organiser(s): Stephen Robinson, Markus Linné and Victor Évora
- Lecture: Inverse estimation of pressure- and shear wave speeds from scattering experiments from spherical samples
Paper ID: 2080
Author(s): Östberg Martin, Linné Markus
Presenter: Linné Markus
Abstract: The pressure- and shear-wave speeds of two rubber-like materials (natural rubber and RenShape) are estimated by inverse estimation from data obtained from scattering experiments on spherical samples. The samples, with a diameter of 0.15 m, are submerged at a depth of 2 m in an 8x4x4 m3 (length, width, depth) tank. The transmitter and receiver are positioned close to the sample using an asymmetrical triangular configuration. The transmitter-to-receiver and transmitter-to-sample distances are approximately 0.6 m and 1.2 m respectively. The configuration is optimized for improving the time separation of scattered waves. The measured scattered field from the spherical sample is matched with the field computed by a wave propagation code.\nBy varying the input parameters (pressure- and shear wave speeds together with associated attenuations) to the code, the difference between measured and modelled data is minimized. This inversion procedure is performed using the global optimization algorithm differential evolution, which is well suited for finding the minimum of the resulting non-linear, non-convex optimization problem.\nThe method in general gives good results for the wave speeds that are reasonably close to that of water. For the determination of the shear wave speed in the natural rubber sample, the relatively slow propagation prohibits a reliable estimation.
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- Corresponding author: Dr Markus Linné
Affiliation: Swedish Defence Research Agency
Country: Sweden
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