The Elastic Properties of Sandwich Structure with Z-pinned Foam Core

Abstract

Z-pinned foam core sandwich is a novel structural material. It is produced by reinforcing lightweight foam core with a truss network of pultruded carbon fiber rods and then laminated between composite face sheets. This investigation presents an approach to obtain the equivalent moduli of Z-pin reinforced foam core. The pins are treated as cylinder inclusions in foam at the same time they act as truss core. Based upon the Mori—Tanaka mean-field theory to account for the interaction between the pins and foam, an analytical approach is developed to assess the effective moduli of foam containing randomly oriented pins. Under the concept of space truss frame, a homogenization model is presented to calculate the effective elastic properties of pins truss core. First-order shear theory is developed to simulate the mechanical behaviors of a Z-pin reinforced foam core sandwich. Then, core shear tests were carried out to check the validity of a theoretical model. Furthermore, numerical examples have been given for a carbon fiber pins reinforced Rohacell foam core. Analysis results indicate that the equivalent moduli of reinforced core are strongly affected by the orientation, the volume fraction, and the properties of Z-pins.

Keywords

three-dimensional reinforcement mechanical properties modeling.

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