关键词: nonlinear Lur’e systems, circle criterion, absolute stabilization, H_∞ control, LMI

Abstract: The axially symmetric torsion of rigid circular shaft of varying diameter embedded in an elastic half space is studied by line-loaded integral equation method (LLJEM), where the problem is formulated by distributions of ficitious fundamental loads PRCHS (point ring couple in half space) along the axis of symmetry in interval of the shaft and is reduced to a one-dimensional and non-singular Fredholm integral equation of the first kind and is easily solved numerically. Numerical examples oftorsin of rigid conic, cylinder, conical-cylinder embedded in an elastic half space are given and compared with the known result obtained, by the others. The exact solution of torsion of rigid half sphere embedded in an elastic half space is also presented.

Key words: nonlinear Lur’e systems, circle criterion, absolute stabilization, H_∞ control, LMI