Repairability of lattice structure in a circular economy: Mechanical response of 3D printed octet-truss lattice structures under quasi-static loading

Repair and maintenance of products require few resources in a circular economy, minimising the environmental impact of manufacturing and use of products. Although lightweight lattice structures have been widely investigated in various fields owing to their advantages in terms of their mechanical characteristics and the development of additive manufacturing, research on lattice structures has focused mainly on process and design methods for structural development, and not on the repair of lattice structures. In the present study, the repairability of lattice structures was studied to extend the lifetimes of lattice-structured products; this would enable the reuse of products and induce people to directly get involved in creating a circular economy. To determine the factors to be considered for repairing lattice structures, standard specimens fabricated in the form of single undivided and adhesively bonded joint samples were fabricated by fused deposition modeling and compared under four quasi-static tests: compression, tensile, shear, and three-point bending. The octet-truss unit cell was used in the specimen with a strut diameter of 1–2.5 mm at 0.5 mm intervals and a length of 10 mm. The difference in mechanical response between the two groups was significant in the tensile and three-point bending tests, while the compressive and shear tests showed similar results. Therefore, determination of the direction of the stress imposed on the products is essential for the proper repair of the underlying lattice structures, prolonging the life cycle of the product and thus leading to a positive effect on the circular economy.Integrated Product Desig