Challenges in Additive Manufacturing of Thin-Walled Structures and Their Applications

Additive manufacturing (AM) offers greater advantages of building intricate geometry and thin-walled structures, with comparable mechanical properties of the feedstock materials, at reduced lead times and material wastage. Utilising the promising feasibility benefits of AM has immensely helped to fabricate thin-walled structures used in aerospace, biomedical, automotive, energy absorption, and other functional applications. However, more benefits present more challenges. The complex thermodynamic phenomena of the AM processes comprise non-uniform phase transitions resulting in thermal residual stresses. Achieving process stability by optimising thermal stresses and other design considerations poses an even bigger challenge due to the presence of a wide array of AM process parameters. Although AM has shown signs of promise to overcome these critical issues associated with fabricating mainstream AM components, the real challenges persist while fabricating thin-walled structures: (i) the most common challenges encountered are the occurrence of inevitable metallurgical defects, anisotropic microstructures, poor surface quality and substandard mechanical properties, especially under dynamic loading conditions, and (ii) the stability challenges associated with AM thin-walled structures are buckling behaviour, inadequate load resistance, and load-sensitive fracture mechanisms. A sincere effort has been made to briefly present the existing challenges, and the applications of AM thin-walled structures have been discussed and summarised.