Mechanical properties and cross-sectional behavior of additively manufactured high strength steel tubular sections

Additive manufacturing, commonly known as 3D printing, is an evolutional technology in the manufacturing industry. This technology has already been embraced by different industries, such as aerospace and biomedical engineering, and the recent advance in this technology has generated a vast of societal excitement for its future. Despite the exciting prospect of its application in civil engineering, additive manufacturing technology is still at a perceived stage for construction industry. The benefits and potential in construction industry are rarely known in the field at this stage. This paper aims to investigate the mechanical properties and structural performance of additively manufactured high strength steel tubular sections at the cross-sectional level through experimental program. The specimens were additively manufactured from H13 steel powder by selective laser melting (SLM) with three different scanning patterns, where the typical yield strength (0.2% proof stress) of the conventionally manufactured H13 steel is around 1650 MPa. The test program comprised tensile coupon tests, compression coupon tests, hardness tests, microstructural characterization as well as geometric imperfection measurements and stub column tests. The anisotropy on mechanical properties was examined through tensile coupon tests in both longitudinal and transverse directions. Compression coupon tests were also conducted to investigate the differential strength of material in tension and compression. The influences of scanning patterns on mechanical properties and structural behavior of as-printed high strength steel tubular sections stub columns were also investigated. The test results were used to assess the applicability of existing design provisions in the American Specification, Australian and New Zealand Standard as well as European Code that originally developed for conventionally produced hot-rolled and cold-formed steel tubular sections to the additively manufactured high strength steel tubular non-slender sections in this study.