Mechanical Characterization of PLA+ Specimens with Different Geometries Using Experimental and Numerical Methods

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Geometric discontinuities are inherent in additively manufactured polymer components.
• Their impact on mechanical response is often unquantified.
• Systematic, geometry-comparative studies are needed.

Purpose of the Study:

• To experimentally and numerically investigate the tensile behavior of FDM-printed PLA+ specimens with varying geometries.
• To quantify the effects of geometric discontinuities on mechanical response.
• To validate a predictive modeling framework.

Main Methods:

• Tensile testing of dog-bone, circular-hole, and U-notched PLA+ specimens (ASTM D638 Type IV).
• Finite element simulations using an experimentally calibrated Ramberg-Osgood elastic-plastic model.
• Comparison of experimental results with simulation predictions.

Main Results:

• Dog-bone specimens showed intrinsic material response (UTS 41-43 MPa, E=3.06 GPa).
• Circular-hole specimens exhibited localized deformation, reduced ductility (1.4-1.6%), and increased apparent modulus (3.17 GPa).
• U-notched specimens displayed severe stress concentration, high apparent modulus (≈5.30 GPa), and brittle fracture (ductility 0.9-1.0%).
• FEA accurately predicted peak stresses (≈42 MPa) and material behavior across geometries.

Conclusions:

• Geometric discontinuities critically influence stress localization, apparent stiffness, and fracture initiation in FDM-printed PLA+.
• The validated Ramberg-Osgood model reliably predicts geometry-dependent mechanical behavior.
• This framework supports geometry-aware design for additively manufactured polymer structures.