| 摘要 |
The invention include a method for improving determination of mode shapes for a mechanical structure where each mode shape is a vector that consist of a number of components and each vector corresponds to a natural frequency of the structure where the method is based on: Measurements performed on the structure using signals from a limited number of sensors such as accelerometers placed on the structure defining the number of components of each of the mode shape vectors, where the measured signals are used to determine a number of mode shapes that are improved by a linear combination of mode shapes from a simplified theoretical model of the structure, where the linear combination comprises a limited number of the mode shape with frequencies around the frequency of the corresponding mode shape of the model. This allows the modified mode shapes to be accurately expanded to all degrees of freedom in the model. The invention further includes applications of the method on mechanical structures such as wind turbines and bridges for i.e. ° determination of stress/strain history and/or prediction of expected service life, ° determination of structural changes such as damages resulting in loss of stiffness ° Illustrating the time history of measured and/or unmeasured quantities that can be derived from the expanded set of modified mode shapes. |
