Fatigue assessment of additively manufactured plain and notched polylactide (PLA)

The present paper investigates the influence of raster orientation as well as of non-zero mean stresses on the fatigue behaviour of additively manufactured plain and notched polylactide (PLA). PLA is a biodegradable polymer that can be 3D-printed easily and at a relatively low cost. The Theory of Critical Distances (TCD) is the name which has been given to a group of fatigue assessment techniques that are all based on the use of a material critical distance. The accuracy and reliability of the TCD in estimating the fatigue lifetime of additively manufactured PLA is assessed against numerous experimental results generated by testing notched specimens containing different geometrical features. The TCD is seen to be highly accurate. This demonstrates that this design approach can be used successfully to design against fatigue also notched components of 3D-printed PLA.