Mode I and II fracture toughness investigation of Laser-Sintered Polyamide

• Published in: Theoretical and applied fracture mechanics Vol. 106; p. 102497
• Main Authors: Linul, Emanoil, Marsavina, Liviu, Stoia, Dan Ioan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.04.2020; Elsevier BV
• Subjects: Density; Four-point bending tests; Fracture toughness; Horizontal orientation; Lased-sintered polyamide; Laser sintering; Mode I and II fracture toughness; Parameters; Polyamide resins; Process energy and spatial orientation; Rapid prototyping; Three dimensional printing; Variance analysis; Vertical orientation; Lased-sintered polyamide; Mode I and II fracture toughness; Process energy and spatial orientation; Four-point bending tests
• ISSN: 0167-8442; 1872-7638
• DOI: 10.1016/j.tafmec.2020.102497

•Large dimensional errors are recorded for lower process energy.•The best dimensional stability was recorded for vertical orientation.•The highest KIC was recorded for vertical orientation and for highest process energy.•The highest KIIC was recorded for horizontal orientation and for highest process energy.•Strong positive correlation: process-structure-fracture toughness was found. This paper presents experimental investigations on the geometrical and fracture properties of specimens obtained by Additive Manufacturing technology. The experimental tests were performed on Single Edge Notch Bend (SENB) specimens obtained through the Selective Laser Sintering process, based on the polyamide PA2200 material. The SENB specimens were manufactured using three different process energies-PEs (E1, E2 and E3), respectively three different spatial orientations-SOs (Vertical-V, Horizontal-H and Oblique-O). Symmetric and asymmetric four-point bending tests were used to determine the mode I and II fracture toughness (KIC and KIIC). It was observed that the density (ρ) of the 3D printed specimens is highly dependent on the PE and SO, the highest density values being obtained for the highest PE (E1), respectively for the V-SO. Maximum relative errors of the main geometrical parameters (thickness, length and width) of the SENB specimens were obtained for E3-PE and H-SO. With respect to the fracture toughness, it was observed that, regardless of PE and SO, the KIC values are higher than KIIC ones. The highest KIC value was found for E1 and V-SO, while KIIC highlight the highest value for E1 and H-SO. Finally, analysis of variance (ANOVA) method is used to analyze the influence of various factors on outcome parameters.