MATERIAL MODELING OF ORTHOPEDIC INSOLES

An experimental setup is presented for the material characterization of rubber-like sensomotoric insoles. This setup consists of local hardness measurements, quasi-static compression tests and dynamic testing using the 4a Impetus II pendulum test system [1]. A correlation between the measure of shore hardness and the stress strain relation of rubber-like materials is presented and verified in order to consider the inhomogeneous properties of insoles due to milling work of the manufacturing process. The dynamic response of the material is modeled by MAT_SIMPLIFIED_RUBBER/FOAM (material no. 181) in LS-DYNA [2] and MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE respectively. The presented modeling technique is capable to describe the entire process chain from milling of the insole up to its usage. A further experimental setup is presented for converting the inlay and the human foot to a finite element model. By means of the Streifenlichttopometrie (SLT) [3] it is possible to record the complete surface of the object in a practically photorealistic fashion, i.e. three-dimensionally. In comparison with the classic method of photogrammetry, Streifenlichttopometrie is remarkably faster (10,000 points/s instead of 1 point/s). In this paper we present a modification of this method towards the measurement of dynamic processes.