Buckling developed in 3D printed PLA cuboidal samples under compression: Analytical, numerical and experimental investigations

In this work, the behaviour of short-length PLA 3D printed elements under compression is investigated, with a specific focus on buckling. An extensive experimental campaign is conducted on square polymeric columns produced via Fused Filament Fabrication (FFF), with the longitudinal axis oriented in the out-of-plane direction in 3D printing coordinate system. Compressive and tensile mechanical properties of FFF 3D printed PLA are determined; an asymmetry in out-of-plane tensile-compressive behaviour is discussed. The compression of the specimens is monitored using a single camera Digital Image Correlation system, supported by a preliminary validation of its set-up. The slenderness ratio at which the elements start to buckle is identified. The experimental results are compared with three analytical models for buckling prediction in isotropic materials and with linear and non-linear Finite Elements (FE) models. For a broad range of slenderness ratio, the tangent modulus theory gave a good, if conservative, estimation of the critical loads when used with the compressive mechanical properties. Furthermore, the predictions of the non-linear FE models were found to be consistent with the experimental results.