On the combined use of averaged strain energy density criteria (ASED) and equivalent material concept (ECC) for the fracture load prediction of additively manufactured PLA v-notched specimens

The growing introduction into the industrial world of additive fused deposition technologies, for producing functional components made of thermoplastic materials (such as PLA), pushes designers to know which methods for predicting breakage under load can be used to design correctly these elements. In particular, this paper analyses the “brittle fracture” phenomenon in these materials that too often occurs in various engineering sectors. This research article investigates a methodology for predicting fracture loads in additively manufactured PLA material specimens with different topologies of V-notches. The proposed method represents a direct evolution of the Average Strain Energy Density (ASED) criterion, originally conceived for brittle materials that develop a liner-elastic behavior. This method, in those cases where the material has a non-linear elastic behavior, has to be correct with the concept of equivalent elastic material (EMC), providing in that way, a simple and reliable method for local settlement prediction in PLA specimens. The results obtained demonstrate that, despite the many variables that come into play in the making process of the specimens, the ASED-EMC combined criteria provide accurate predictions. The breaking load was predicted with an average deviation from the experimental fracture loads of less than 12%.