MODELLING AND IDENTIFICATION OF BOUNDARY CONDITIONS IN FLEXIBLE STRUCTURES

An approach is presented to model and to identify boundary conditions in structures. The unknown boundary conditions are modelled as axial and torsional springs at the boundaries. These springs can be discrete or continuous. The boundary conditions are identified by finding the spring constants, making use of the orthogonality conditions and the system eigenvectors. The importance of knowing the boundary conditions accurately is discussed and guidelines are developed to determine how accurately the boundary conditions have to be known. Implementation aspects associated with the identification are considered, such as the accuracy with which the spring constants can be identified and the effects of spatial discretisation.