Mechanical responses of titanium 3D kagome lattice structure manufactured by selective laser melting

Three dimensional (3D) kagome lattice structure incorporates excellent mechanical and actuation performances. Thus, here, 3D kagome lattice structures were fabricated by selective laser melting with titanium alloy. The mechanical responses under compression and three point bending were experimentally tested and compared with the theoretical predictions. With the increased relative density from 2.8% to 5.5% and 9.1%, the average compressive strength significantly enlarges from 2.0 MPa to 8.0 and 17.5 MPa, and the average bending load capacity increases from 260.0 N to 850.0 and 1750.0 N. We reveal that different from other lattice structures which usually present sole buckling or fracture failure, kagome lattice structure exclusively presents mixed failure model of both buckling and fracture. The buckling failure always arises first, and follows by the subsequent fracture. Thus, the experimental strength and load capacity are close to but a little higher than the theoretical predictions under buckling. Moreover, critical relative densities between the buckling and fracture failure models are analytically established. It is revealed that in order to significantly raise the strength and load capacity, the failure model should be respectively designed as fracture and buckling corresponding to the condition that the relative densities are respectively lower and higher than the critical relative densities. The results obtained here provide potential application of the lightweight structures for aerospace, civil and transportation engineering.