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A three-dimensional, continuum mechanical model for additively manufactured polyamide 12

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Dominik Hahne at University of the Bundeswehr Munich
Dominik Hahne
Michael Johlitz
Michael Johlitz
Michael Johlitz
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Alexander Lion
Alexander Lion
Alexander Lion
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Abstract and Figures

Polyamide 12 (PA12) is a semi-crystalline thermoplastic used in the automotive and aerospace industries due to its high resistance to chemicals and abrasion and its good thermal stability. The material can be processed with various manufacturing technologies, including selective laser sintering (SLS), which offers great potential for industrial production due to its excellent and reproducible mechanical properties and thus motivates a detailed understanding of the mechanical behavior. This paper presents an approach for modeling the mechanical behavior of selectively laser-sintered polyamide 12. A continuum mechanical model is developed based on a comprehensive temperature and velocity-controlled experimental program, and its parameters are identified. After presenting the test specimens developed in-house, which utilized the geometric freedom of the SLS process, the kinematic description of the test specimens and the digital image correlation technique used for this purpose are discussed. The experimental test results are then presented, which consist of relaxation tests and experiments with a constant strain rate at various temperatures. After the two material-theoretical approaches of linear viscoelasticity and endochronic plasticity have been presented, the material model is derived in three dimensions, and the parameters are identified.
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Continuum Mech. Thermodyn. (2025) 37:39
https://doi.org/10.1007/s00161-025-01369-w
ORIGINAL ARTICLE
Dominik Hahne ·Michael Johlitz ·Alexander Lion
A three-dimensional, continuum mechanical model for
additively manufactured polyamide 12
Received: 14 September 2024 / Accepted: 13 February 2025 / Published online: 11 March 2025
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025
Abstract Polyamide 12 (PA12) is a semi-crystalline thermoplastic used in the automotive and aerospace
industries due to its high resistance to chemicals and abrasion and its good thermal stability. The material
can be processed with various manufacturing technologies, including selective laser sintering (SLS), which
offers great potential for industrial production due to its excellent and reproducible mechanical properties
and thus motivates a detailed understanding of the mechanical behavior. This paper presents an approach
for modeling the mechanical behavior of selectively laser-sintered polyamide 12. A continuum mechanical
model is developed based on a comprehensive temperature and velocity-controlled experimental program,
and its parameters are identified. After presenting the test specimens developed in-house, which utilized the
geometric freedom of the SLS process, the kinematic description of the test specimens and the digital image
correlation technique used for this purpose are discussed. The experimental test results are then presented,
which consist of relaxation tests and experiments with a constant strain rate at various temperatures. After the
two material-theoretical approaches of linear viscoelasticity and endochronic plasticity have been presented,
the material model is derived in three dimensions, and the parameters are identified.
Keywords Polyamid 12 ·PA1 2 ·Constitutive modelling ·Viscoelasticity ·Endochronic plasticity ·
Selective laser sintering
1 Introduction and motivation
The material polyamide 12 (PA12), also known as nylon 12, is a versatile, semi-crystalline thermoplastic.
In particular, its high resistance to chemicals and abrasion and good thermal stability make it suitable for
use in (fuel) hoses, cable sheathing, connecting pieces, seals, and similar applications in the automotive and
aerospace industries. Due to its biocompatibility, it can also be used in medical products. In addition, the
material properties allow a range of manufacturing technologies. In addition to classic injection molding, the
material can also be processed additively, whereby it should be expressly emphasized that both the FFF process
(fused filament fabrication) and laser-based manufacturing processes can be used here [10].
Among additive manufacturing processes, selective laser sintering (SLS) offers great potential for
industrial-scale production. The reasons for this are the excellent and reproducible mechanical properties,
high toughness, and great geometric freedom compared to tool-based manufacturing technologies. Further-
more, the tool-free process enables a high degree of functional integration and streamlines the production
process in terms of set-up times [11,37,59].
Please refer to the relevant literature on the process of selective laser sintering (SLS), e.g. [60]. There are
several publications on the process itself, its associated parameters, and the materials used. One publication,
D. Hahne (B
)·M. Johlitz ·A. Lion
Institute of Mechanics, Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85579 Neubiberg, Germany
E-mail: dominik.hahne@unibw.de
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
ResearchGate has not been able to resolve any citations for this publication.
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