Application Of The Variational Theory Of Complex Rays To The Determination Of Shock Induced Vibration Of A Rc Structure

Security and safety are crucial aspects in the design of nuclear engineering structures. Civil engineering design and the qualification of materials to dynamic loads must consider the accelerations which they undergo. These accelerations could integrate not only seismic activity but also shaking movements consecutive to aircraft impacts with higher cutoff frequency. Current methodologies for handling such a shock in the calculation stage are based on transient analyzes using classical finite element methods associated with explicit numerical schemes or projection on modal basis. In both cases, to represent in a meaningful way a medium frequency content, a fine mesh is required, which is hardly compatible with the size of models of the civil engineering structures. In order to extend the current industrial methodologies and to allow a better representation of the behavior of the structure in the medium frequency range, an approach coupling a temporal and non-linear analysis of the impact area with a frequency approach for the treatment of the resulting shaking with the Variational Theory of Complex Rays (VTCR) has been developed [1]. The aim is to use the computational efficiency of the implemented strategy and to include the medium frequency range to calculate the nuclear structures response to an aircraft impact. 1 INTRODUCTION For nearly three years in the framework of pre-normative research in nuclear construction (RENON), the constructability research institute (IRC) focused some of its efforts on improving the characterization of floor response spectra in the case of aircraft impacts. The study of airplane crash in the design and verification of nuclear engineering structures has two important and distinct aspects: (i) the resistance of the structure subjected to an impact, loading, and (ii) the qualification of inner equipments to the vibrations induced. The calculation of the resistance of the structure and its design do not generally raise problem with current methods, however, the calculation of induced vibrations, although few harmful to inner equipments, requires special attention, especially with the lack of efficiency of current approaches. Indeed the calculation of floor response spectra (FRS) in this case generally exhibits a set of high magnitude accelerations within a frequency range that is generally much higher than the one observed when calculating the FRS due to an earthquake. The