Contents lists available at ScienceDirect Engineering Fracture Mechanics journal homepage: www.elsevier.com/locate/engfracmech Experimental determination and numerical simulation of material and damage behaviour of 3D printed polyamide 12 under cyclic loading Daniela Schob a,⁎ , Ilja Sagradov a , Robert Roszak a,d , Holger Sparr a , Rainer Franke a , Matthias Ziegenhorn a , Andreas Kupsch b,1 , Fabien Léonard b , Bernd R. Müller b , Giovanni Bruno b,c a Brandenburg University of Technology Cottbus-Senftenberg, Universitätsplatz 1, 01968 Senftenberg, Germany b BAM, Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, 12205 Berlin, Germany c University of Potsdam, Institute for Physics and Astronomy, Karl-Liebknecht-Str.25, 14476 Potsdam, Germany d Poznan University of Technology, Pl.M. Sklodowskiej-Curie 5, 60-965 Poznan, Poland ARTICLEINFO Keywords: 3D printing Polyamide 12 Chaboche model GTN model Material and damage behaviour X-ray refraction computed tomography ABSTRACT The material and damage behaviour of additively manufactured polyamide 12 under cyclic loading was characterized by cyclic tests and microstructure analysis by using microscopy, X-ray refraction, and computed tomography. The results were used to determine parameters for the viscoplastic material model by Chaboche and a damage model by Gurson-Tvergaard-Needleman. The temperature was monitored during the experiments and the self-heating effect was observed. By including this effect, a higher accuracy could be achieved with the results of mechanical experiments. 1. Introduction Over the past decades, plastics have increasingly found their way into the production of components in various industries, such as automotive engineering and aerospace. Their areas of application have also become more complex, with the result that plastics are increasingly being used as structural materials today. The manufacturing processes for plastic components have also changed: e.g., additive manufacturing has become more and more important. At the beginning, this manufacturing process was primarily used for prototyping. However, the field of application has expanded. In order to satisfy the new requirements, it is essential to introduce new test methods for additively manufactured materials. Currently, the number of testing standards for additive manufactured (AM) materials is very limited. In 2015, Forster [1] reported that 47 standards exist, but 27 of them cannot be applied and 20 are only partially applicable. In addition to this challenge, the manufacturing processes are not yet optimized, as proven by investigations of the material structure [2]. Since no test standards are available, it is not possible to obtain material parameters from data sheets. Having such standards would allow future qualification and standardization of AM parts. In a previous study [3] we analysed the material and damage behaviour of selective laser sintered (SLS) PA12 under quasi-static loading. Based on microstructures as obtained from X-ray refraction and computed tomography, a porosity of 5% of the virgin https://doi.org/10.1016/j.engfracmech.2019.106841 Received 16 July 2019; Received in revised form 29 November 2019; Accepted 21 December 2019 ⁎ Corresponding author. E-mail addresses: daniela.schob@b-tu.de (D. Schob), andreas.kupsch@bam.de (A. Kupsch). URLs: http://www.b-tu.de (D. Schob), http://www.bam.de (A. Kupsch). 1 Principal corresponding author. Engineering Fracture Mechanics 229 (2020) 106841 Available online 06 March 2020 0013-7944/ © 2019 Published by Elsevier Ltd. T