An approach to construct a three-dimensional isogeometric model from μ-CT scan data with an application to the bridge of a violin

• Published in: Computer aided geometric design 2020-03, Vol.78, p.101815, Article 101815
• Main Authors: Marschke, Sandra, Wunderlich, Linus, Ring, Wolfgang, Achterhold, Klaus, Pfeiffer, Franz
• Format: Article
• Language: English
• Subjects: Geometry construction; Isogeometric analysis; NURBS volume; Spline fitting; Vibro-acoustics; μ-CT scan data
• ISSN: 0167-8396; 1879-2332
• DOI: 10.1016/j.cagd.2020.101815

•A robust Spline fit by a Gauss-Newton approach with regularisation avoids overfitting.•The resulting geometry can be directly used for isogeometric numerical simulations.•Workflow for the vibro-acoustical simulation of a violin bridge based on a μ-CT scan. We present an algorithm to build a ready to use isogeometric model from scan data gained by a μ-CT scan. Based on a three-dimensional multi-patch reference geometry, which includes the major topological features, we fit the outline, then the cross-section and finally the three-dimensional geometry. The key step is to fit the outline, where a non-linear least squares problem is solved with a Gauss-Newton approach presented by Borges and Pastva (2002). We extend this approach by a regularisation and a precise interpolation of selected data points. The resulting NURBS geometry is ready for applying isogeometric analysis tools for efficient numerical simulations. As a particular example we examine the scan data of a violin bridge and present the complete workflow from the μ-CT scan up to the numerical simulation based on isogeometric mortar methods. We illustrate the relevance of the constructed geometry with a vibro-acoustical application.