Increasing flexural performance of hybrid sandwich panels by using strain hardening cementitious base composite and glass fiber-reinforced polymer

The present paper explores different techniques for increasing flexural performance of composite sandwich panels made of hand-layup glass fiber reinforced polymer skins and low density closed cell polyurethane foam core. An experimental program compares the performance of simple panels face to the use of transversal and longitudinal internal glass fiber reinforced polymer ribs and the installation of a strain hardening cementitious base composite top layer over the panels. Based on the experimental results, finite element models are also developed to simulate the flexural behavior of tested panels and conducted an in depth analysis of the techniques studied. Obtained experimental and numerical results show that the use of internal glass fiber reinforced polymer ribs (especially in longitudinal direction) along with the use of strain hardening cementitious base composite significantly and effectively increases the flexural performance of sandwich panels. The high stiffness to weight ratio capacity of the panels attained by applying the proposed method enables its use in rehabilitation of historical places. Furthermore, the proposed techniques could be helpful for strengthening available composite sandwich panels.