1. A method for comparing two mode shapes of a multi-component structure, comprising: forming, by a validation tool residing in memory, a first mode shape vector and a second mode shape vector for a first mode shape and a second mode shape of the multi-component structure, respectively, by grouping modal displacement at each node associated with each component in the multi-component structure: squaring sum of magnitudes of correlation of the modal displacement at each component for the first mode shape vector and the second mode shape vector in the multi-component structure by the validation tool; computing a product of squared magnitudes of the first mode shape vector and the second mode shape vector of the multi-component structure by the validation tool; computing by the validation tool, modal assurance criterion between the first mode shape vector and the second mode shape vector of the multi-component structure by dividing the squared sum of magnitudes of the correlation of the modal displacement at each component for the first mode shape vector and the second mode shape vector in the multi-component structure with the computed product of squared magnitudes of the first mode shape vector and the second mode shape vector of the multi-component structure; and comparing, by the validation tool, the first mode shape and second mode shape of the multi-component structure using the computed modal assurance criterion to identify similarity between the two mode shapes of the multi-component structure.