Preparation And Mechanical Properties Of Cfrp Composite Tetrahedral Lattice Truss Structures

In recent years, the lattice truss core sandwich structures are attracting interest as lightweight multifunctional materials due to their high specific strength and stiffness and other functions such as actuation, heat dissipation or stealth. The truss members in lattice materials can be topologically configured to experience predominantly axial stress (tension or compression), no matter the sandwich panels are loaded in bending or shear. This can obtain the minimum weight under the same load competitive with other conventional cores. For their superior tensile capacity and high specific strength/stiffness, carbon fiber reinforced polymer (CFRP) composites are very suitable to fabricate lattice truss structures. The fabricating and mechanical behavior of CFRP composite tetrahedral lattice truss structures are the main objects in this thesis.The silicon rubber mold was designed and prepreg lay-up process was utilized to manufacture CFRP composite tetrahedral lattice truss structures. The mechanical properties of this structure were studied by compressive, shear, three-point bending and in-plane tests. The splitting of truss members was observed in the compressive test. The dominant failure mode of this structure under shear and bending tests was nodal failure. Under in-plane loading, inter-ply delamination occurred first in a facesheet owing to compression, which leaded to the buckling of the total structure.Compared with the conventional sandwich core, CFRP composite tetrahedral lattice truss cores are higher specific strength and can be designed in more aspects. In addition, the large interconnected void space within lattice cores provides numerous multifunctional opportunities.