Isogeometric boundary element analysis and structural shape optimization for Helmholtz acoustic problems In this thesis a new approach is developed for applications of shape optimization on the time harmonic wave propagation (Helmholtz equation) for acoustic problems. This approach is introduced for different dimensional problems: 2D 3D axi symmetric and fully 3D problems. The boundary element method (BEM) is coupled with the isogeometric analysis (IGA) forming the so called (IGABEM) which speeds up meshing and gives higher accuracy in comparison with standard BEM. BEM is superior for handling unbounded domains by modeling only the inner boundaries and avoiding the truncation error present in the finite element method (FEM) since BEM solutions satisfy the Sommerfeld radiation condition automatically. Moreover BEM reduces the space dimension by one from a volumetric three dimensional problem to a surface two dimensional problem or from a surface two dimensional problem to a perimeter one dimensional problem. Non uniform rational B splines basis functions (NURBS) are used in an isogeometric setting to describe both the CAD geometries and the physical fields. ...