A Projection Transformation Method for Nearly Singular Surface Boundary Element Integrals

This study proposes a numerical integration method for nearly singular integrals over general curved surfaces, arising in three dimensional boundary element analysis. Nearly singular integrals frequently occur in engineering problems involving thin structures of gaps and when calculating the field near the boundary. Numerical experiments show that the method is far more efficient compared to previous methods and is robust concerning the type of integral kernel and position of the source point. Theoretical error estimates for the method are derived using complex function theory. The method is also shown to be applicable to weakly singular and hypersingular integrals. Knowledge in basic calculus is assumed. The book is intended for engineers and researchers using the boundary element method who require accurate methods for numerical integration and also for numerical analysts interested in an application area for numerical integration.