[en] Scale model tests are often used in developing solutions to problems where theory alone is inadequate and full-scale tests are too costly. In this paper the author reviews the physical basis for scale model tests, together with their limitations, and presents examples of the effective use of scale model tests in past and current R and D work in structural dynamics. Scale model tests are particularly attractive in LMFBR safety investigations of containment integrity under loads due to and HCDA, sodium-water interaction in a heat exchanger, or plant missile impact. Past scale model work on these problems has yielded valuable results, and future applications are envisaged. (Auth.)