Evaluation of flexural-stiffening for elastomeric pE/EVA foam panels using a stress-dependent adaptive FE model

Flexural-stiffening, as is typical of many polymeric materials, leads to the observation of a stiffer reaction for materials under flexural conditions than what is expected usually according to their membrane load carrying response. The concern of this study was the establishment of a technique to evaluate the flexural-stiffening of some beam and panel specimens, made of an elastomeric foam polymer (PE/EVA), by comparison of the load-deflection results obtained by the experiments and the stress-dependent adaptive models which were cultured by the membrane response of the material. The adaptive model showed that there was a larger volume of material with tensile stress for the specimens with a larger influence of flexural-stiffening. For a square foam panel, based on the initial part of load-deflection curves, the volume of the tensile material and the value of flexural-stiffening were obtained as 98% and 56%, respectively, while these parameters were evaluated as 65% and 6% by taking into account the overall load carrying performance of the specimen. The significant finding of this study was the reliability and efficiency of the adaptive models to be employed for evaluation of the flexural-stiffening in the complex materials.