Adjustment of the Boundary Conditions in a Finite Element Model of a Plate Suspended With Springs by an Inverse Method

Abstract

The aim of this study is to determine the material properties of composite structures in function of temperature. Identification of material properties using vibration-based mixed numerical experimental techniques [MNETs] often takes a freely suspended rectangular plate as test configuration [1]. However, in a remote-controlled furnace, contactless acoustic excitations are used and the vibration amplitude is registered contactless with a laser beam or camera. In this configuration, a plate with a free-free suspension is difficult to position in a stable way. An alternative in such cases is the suspension of the specimen using steel helical extension springs. Figure 1 shows a possible suspension configuration. The mass, stiffness and damping of the suspension springs influences the structural vibration. Material identification by using vibrationbased mixed numerical experimental techniques [MNETs] can only be successfully applied if the mathematical model - which is solved using the finite element method - is appropriate [1,2]. The mathematical model is appropriate if it represents mass, stiffness and damping properties of the physical test setup in sufficient detail.