STRAIN ANALYSIS ON DUCTILE CAST-IRON CONTAINERS AT DROP TESTS

Ductile cast iron (DCI) containers for transportation and deposition o f radioactive waste have to be designed carefully in order to avoid un acceptable damages and leakages in case of an accident. Therefore vari ous calculations and experimental methods are used during development and licensing of the containers. Besides others the container has to s uffer severe impacts (e.g. falling from a height of several meters ont o a concrete base). The level of strains must not exceed a value which would adversely affect the package in such a way that it would fail t o meet the applicable requirements. In practice complex events such as drop tests are very difficult to calculate. Both the position of maxi mum stress and the time of its occurrence are not easily predicted wit h the method of FEM. The uncertainty of the material modelling for pla stic deformation by dynamic loading rates is the limiting factor. Ther efore holography as an integral measuring technique in combination wit h strain gauge techniques were used to fit the FEM. By using the FEM c alculations in the case of licensing, the FE and the material model ha ve to be verified. The verification of the FE model has to be done by comparison of the local maxima measured by strain gauges and by compar ison of the vibration modes. These vibration modes we take from hologr aphic measurements. In this paper we explain container vibrations afte r impact analysed with holographic measurements, FEM calculations and the comparison of the results. The comparison of the local maxima (str ain gauges/FEM) is reported elsewhere (Schreiber, D. et al., 1993. Tra ns. 12th Int. Conf. J04, 5, pp. 101-108; Volzer, W. et al., 1997. Tech nical Semin. on Brittle Fracture. Krefeld 27-28.10.94, RAMTRANS (in pr ess)). (C) 1997 Elsevier Science S.A.