Study On Shear Performance Of The Partition Reinforced Composite Sandwich Beams With Foam Core

Foam core composite sandwich structure is valued for its light weight, high strength and large stiffness. Nowadays, foam core sandwich structure has been widely used in aerospace, ship and other fields. The studying object of this article is partition reinforced foam core composite sandwich beam which was cut from sandwich panel co-cured at room temperature, and with FRP as its faces and partition, foam as its core. Studies show that under transverse shear loading, the classical failure mode of foam core sandwich structure is shear crack of the core as well as the interfacial debonding. The method of partition reinforced and the co-cured process enable the unity of GFRP partitions、foam core and GFRP faces, hence the interfacial construction is improved. Three kinds of partition reinforced sandwich structures were introduced, which were diaphragm reinforced, longitudinal partition reinforced and bi-directional partition reinforced composite sandwich structures respectively. In this article, experimental study, theoretical analysis and numerical simulation were conducted to study the shear behavior of partition reinforced foam core composite sandwich structure. The main research contents and conclusions were as follows:(1) The shear performance of diaphragm reinforced sandwich beams with 150kg/m3 foam core were tested through three point shear tests. The influence of diaphragm reinforced method as well as the different space of diaphragms on sandwich beams’shear performance were analyzed when comparing with the neat foam core sandwich beams.(2) On the basis of shear test of sandwich beams with 150kg/m3 foam core, two effective diaphragm spaces were chosen to further analyze the shear performance of beams with 60kg/m3 foam core and compare the diaphragm reinforced ones with neat foam core sandwich beams. The good and limiting aspects of the diaphragm reinforced method were analyzed in detail. At the same time, two other kinds of web reinforced, longitudinal partition reinforced and bi-directional partition reinforced, sandwich beams were adopted and tested in order to make up above limitations.(3) Based on the Hoff sandwich structure and Timoshenko beam theory, the deformation and stiffness of diaphragm reinforced foam core sandwich beams were derived through geometrical and energy method by considering the joint influence of bending and shearing on deformation. At the same time, the ultimate bearing capacity of diaphragm reinforced and longitudinal partition reinforced sandwich beams was derived on the basis on three different failure principles and failure mode analysis and was proved reasonable, as compared with experimental results. What’s more, numerical simulation were conducted and compared with experimental and theoretical results.