An inverse approach to the accurate modelling of 3D-printed sandwich panels with lattice core using beams of variable cross-section

With the development of additive manufacturing (AM), lattice structures are gaining ever-increasing popularity in lightweight and multi-functional design. Due to the big difference in the size scales of unit cell and lattice structure, existing numerical methodologies adopting solid elements may lead to large models that are both costly and time-consuming. Taking into account both the material concentration in the vicinity of the intersecting nodes and general defects in the member struts issued from AM, we propose in this present work a novel approach for the modelling of lattice structures based on beam elements with variable cross-section. The geometric parameters that characterize the non-uniform beams are calibrated with experimental data by an inverse approach. The calibrated model has been fully validated on both numerical and experimental data, and it is shown to achieve an analysis accuracy that is comparable to the one obtained from the corresponding model based on solid elements. The resulting efficiency improvement is expected to accelerate the optimization phase of the lattice core for more advanced or tailored performances of sandwich panels.