The Experiment and Finite Element Analysis of Carbon Fiber Sandwich Beam With Pyramidal Truss Core Structure

Abstract

A new technology method is adapted to manufacture carbon fiber lattice sandwich beam with pyramidal truss core. The flat crush test experiment is to test the resistance to compression of the carbon fiber sandwich plate with pyramidal truss core. The result shows that after the pressure head contact the specimens adequately, and the stiffness of structure is the maximum. If the load is continuing increase, the pyramidal truss core may be destroyed, and both sides of the carbon fiber panel begin tottering. It emerges permanent deformation on the structures after an uninstall. The three-point bending test of lattice sandwich beam referred to ASTM C393-00 is designed to research the mechanical properties of face sheet and pyramidal truss core of lattice sandwich beam with theoretical analysis. Load-deflection curves of the middle of lattice sandwich beam in long span and in short span tests are retained, which are applied to obtain flexure stiffness of face sheet and shear strength of pyramidal truss core. It is found that span length has some influence on damage modes of lattice sandwich beam with pyramidal truss core. Debonding between face sheet and lattice core occurs when span is larger and core collapse appears when span is smaller. Crack expansion and fracture of resin base also both emerge in these two damage modes and the crack expansion consists of two different types which are crack expansion inside the resin base and crack expansion from the indenter to the support. Contrast with other lattice sandwich beam with similar or different shapes of core in the other references, the mechanical properties of this lattice sandwich beam by this new fabrication have obvious advantage at the same relative density.