  Having the application in structural health monitoring in mind, we propose
reduced port spaces that exhibit an exponential convergence for static
condensation procedures on structures with changing geometries for instance
induced by newly detected defects. Those reduced port spaces generalize the
port spaces introduced in [K. Smetana and A.T. Patera, SIAM J. Sci. Comput.,
2016] to geometry changes and are optimal in the sense that they minimize the
approximation error among all port spaces of the same dimension. Moreover, we
show numerically that we can reuse port spaces that are constructed on a
certain geometry also for the static condensation approximation on a
significantly different geometry, making the optimal port spaces well suited
for use in structural health monitoring.
