Abstract: In this study, resin-based glass fiber reinforced composite (GFRP) plate spring was designed with a brick type toughening structure by the arrangement form of mother-of pearl mineral structural elements to improve the interlayer toughness of GFRP plate springs,thereby improving their fatigue life. The same size brick masonry type structure and non-toughened structure shrinkage plate spring samples were produced, and the ply laying method was based on the decreasing design principle of variable thickness ply laying. And the mechanical properties of brick structure and non-toughened structure GFRP plate spring were compared by stiffness test, fatigue test and residual stiffness test. The experimental results show that compared with the GFRP plate spring of the non-toughened structure, the stiffness of the GFRP plate spring of the brick structure is reduced by 8.4%, and the fatigue performance is improved by 28.99%. During the fatigue test, the non-toughened structure is completely broken without residual stiffness, and the GFRP plate spring of the brick toughened structure still has the original stiffness of 43.52%. The fatigue failure of GFRP plate springs without toughened structure is in the form of delamination between the layers and complete fracture of the structure. In contrast, the fatigue failure of the toughened structure GFPR plate springs is in the form of interlaminar delamination being blocked and the structure forming a local fracture, for which the fracture cross section is stepped after the residual stiffness test.

Key words: brick bionic structure, GFRP, plate spring, interlayer toughening, fatigue test