Analysis of additively manufactured notched PLA plates using failure assessment diagrams

Abstract

This paper provides a methodology for the estimation of the load-bearing capacity of additively manufactured (AM) PLA plates containing different types of notches (U-notches, V-notches and holes). The methodology is based on the use of Failure Assessment Diagrams (FADs), which are the main fracture-plastic collapse assessment tool provided by structural integrity assessment procedures, such as BS7910 and API 579-1/ASME FFS-1. When analyzing notch-type defects, the FAD methodology requires the application of a notch correction which, in this work, is based on the Theory of Critical Distances (TCD) and the Creager-Paris stress distribution ahead of the crack-tip. The results show that the FAD methodology can be efficaciously applied in this AM polymer, providing safe conservative estimations of critical loads in U-notched and V-notched plates, and accurate slightly unsafe estimations in plates with central hole. The cracking behavior in the different tested plates is a complex procedure generated by a combination of filament failures and debonding processes.