Towards behavior by design: A case study on corrugated architectures

Abstract

A design strategy, referred to as behavior by design, was introduced to develop novel architectured materials starting from their expected stress-strain response. Target behaviors in this strategy have unusual shapes that provide new functions to the material. Here, a numerical toolbox was employed to predict the geometry of metal tensile samples with a corrugated gauge section, given the expected characteristics of their stress-strain response. A multiscale approach, based on a finite element model, was used to construct characteristic points and indices on the macroscopic stress-strain curves to select the relevant input geometrical parameters. Additive manufacturing (electron beam melting) was employed to build several predicted geometries in Ti-6Al-4V titanium alloy. Mechanical testing revealed a good agreement between the experimental and predicted behaviors with limited difference in strain (0.8%) and stress (50 MPa). Shape variations such as local thickness fluctuations were identified using X-ray tomography as a source of mismatch between simulations and experiments. The ability to control the whole shape of unusual stress-strain curves is expected to bring new exciting functionalities to architectured materials. Keywords: Behavior by design, Additive manufacturing, Architectured materials, Strain hardening, X-ray tomography