A New procedure for finite and boundary element methods

ABSTRACT A NEW PROCEDURE FOR FINITE AND BOUNDARY ELEMENT METHODS KANBERBahattin Ph.D. in Mechanical Eng. Supervisor: Assoc. Prof. Dr. İbrahim H. GÜZELBEY June 2001, 121 Pages In this study, coupling processes have been carried out using a conventional approach and a new proposed approach. These approaches are based upon distribution matrix and stress-traction equilibrium ideas on interface line of finite and boundary element regions using the sub-regional technique of boundary element method. Furthermore the stress based finite elements have been derived and it has been involved into coupling process. In the first approach, the derivation of the distribution matrix at the interface line of displacement based finite element or stress based finite element and boundary element regions has been carried out. The interface nodal forces are transformed into the interface nodal tractions using the distribution matrix for coupling purpose. The second approach has been designed using stress-traction equilibrium at the interface line. The finite element and boundary element regions have been treated as sub- regions of whole domain. The coupling operation has been carried out in two different ways. In the first one, the FEM region has been treated as a BEM region. In the second one, the BEM region has been treated as FEM region. The derived elements and designed approaches have been verified by using a number of case studies, with analytical solutions and ANSYS. Key Words: Finite Element Method, Boundary Element Method, Coupling of FEM and BEM, Assumed Stress Finite Elements. m