Study of innovative steel 3D-printing process for structural engineering applications

Over the last decade, Additive Manufacturing (AM) has gained wide importance on several industrial fields, with however severe limitations in the dimensions on the outcomes, constrained to the limits imposed by the printer environment. As such, the applications of these innovative manufacturing technologies in construction have been limited to few explorations on small pieces, to be used as connection parts. With the advent of a new weld-based AM process, referred to as Wire-and-Arc Additive Manufacturing (WAAM), the scale of the printed outcomes increased up to several meters span, thus becoming suitable for real-scale applications in construction. Nonetheless, the outcomes from the printing process require specific considerations for structural design purposes in terms of geometrical irregularities and marked anisotropy As such, the study is focused on the characterization of WAAM-produced 308LSi stainless steel for structural applications and divided in three parts: Part A, Part B and Part C. Part A and B are devoted to study the so-called “continuous printing” strategy, to realize planar elements, and “dot-by-dot printing” strategy, to realize lattice and rod-like elements, respectively. Both parts are articulated as follows: (i) definition of a suitable design approach from the specifics of the printing process; (ii) experimental characterization of the WAAM-produced elements from the microstructural, geometrical and mechanical points of view; (iii) calibration of an orthotropic material model and definition of first design guidelines (according to Eurocode provisions); (iv) exploration of topologically-optimized shapes for new structural members realized with WAAM. Part C is devoted to present new technologies and future developments on WAAM applications in construction. It is articulated as follows: (i) presentation of a new mobile 3D printing system; (ii) exploration of new perspectives for real-time monitoring systems.