Relative significance of in-situ work-hardening in deformation-formed micro-truss materials

Micro-truss cellular materials have enhanced weight-specific properties due to the efficient arrangement of their internal load-bearing ligaments. The present study addresses the incorporation of in-situ work-hardening as a microstructural design strategy in deformation-formed micro-truss materials. First, the tensile properties of the starting perforated precursor material were used to develop a simple analytical model to characterize the plastic strain introduced during fabrication and the range of accessible cellular architectures that can be formed. Second, the flow stress of the individual struts during forming was used to develop a model for predicting the inelastic buckling resistance of the micro-truss struts. The result is a model capable of defining the regions of strength-density material property space that are achievable for a perforation-stretched micro-truss, based simply on the tensile properties of the starting precursor sheet.