TY - JOUR

T1 - Quantification Approaches for Fatigue Crack Resistance of Thermoplastic Tape Layered Composites with Multiple Delaminations

AU - Khudiakova, Anastasiia

AU - Brunner, Andreas J.

AU - Wolfahrt, Markus

AU - Pinter, Gerald

N1 - Funding Information: Funding: The research work was performed within the COMET project VI-2.06, ‘New strategies towards laser assisted manufacturing of fibre reinforced thermoplastic composites,’ at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET program of the Federal Ministry for Transport, Innovation and Technology and the Federal Ministry of Science, Research and Economy with contributions by Technical University of Munich (Institute for Carbon Composites), Montanuniversitaet Leoben (Institute of Material Science and Testing of Polymers), AFPT and Cevotec. The PCCL is funded by the Austrian Government and the State Governments of Styria, Lower Austria and Upper Austria. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/3/17

Y1 - 2021/3/17

N2 - Automated tape placement with in-situ consolidation (ATPisc) is a layer-wise manufacturing process in which the achievement of proper interlayer bonding constitutes one of the most challenging aspects. In the present study, unidirectional carbon fiber reinforced thermoplastic laminates were produced following different manufacturing protocols using ATPisc. The interlayer bonding of the laminates produced was characterized by mode I fatigue fracture tests with double cantilever beam (DCB) specimens. Independent of the manufacturing approach, the laminates exhibited multiple cracking during DCB testing, which could not be evaluated simply following standard methods. Thus, various data analysis methodologies from literature were applied for the quantitative assessment of the fracture behavior of the laminate. The examination of the evolution of the damage parameter φ and the effective flexural modulus throughout testing enabled a better understanding of the damage accumulation. The Hartman-Schijve based approach was revealed to be a convenient method to present fatigue crack growth curves of laminates with multiple delaminations. Moreover, a preliminary attempt was made to employ a ‘zero-fiber bridging’ methodology to eliminate the effect of additional damage processes on the fatigue crack growth that resulted in large-scale, partially massive fiber bridging.

AB - Automated tape placement with in-situ consolidation (ATPisc) is a layer-wise manufacturing process in which the achievement of proper interlayer bonding constitutes one of the most challenging aspects. In the present study, unidirectional carbon fiber reinforced thermoplastic laminates were produced following different manufacturing protocols using ATPisc. The interlayer bonding of the laminates produced was characterized by mode I fatigue fracture tests with double cantilever beam (DCB) specimens. Independent of the manufacturing approach, the laminates exhibited multiple cracking during DCB testing, which could not be evaluated simply following standard methods. Thus, various data analysis methodologies from literature were applied for the quantitative assessment of the fracture behavior of the laminate. The examination of the evolution of the damage parameter φ and the effective flexural modulus throughout testing enabled a better understanding of the damage accumulation. The Hartman-Schijve based approach was revealed to be a convenient method to present fatigue crack growth curves of laminates with multiple delaminations. Moreover, a preliminary attempt was made to employ a ‘zero-fiber bridging’ methodology to eliminate the effect of additional damage processes on the fatigue crack growth that resulted in large-scale, partially massive fiber bridging.

KW - Automated tape placement

KW - Crack branching

KW - Damage index

KW - Double cantilever beam

KW - Interlayer bonding

KW - Mode I fracture

KW - Multiple delaminations

UR - http://www.scopus.com/inward/record.url?scp=85103271507&partnerID=8YFLogxK

U2 - 10.3390/ma14061476

DO - 10.3390/ma14061476

M3 - Article

AN - SCOPUS:85103271507

VL - 14.2021

JO - Materials

JF - Materials

SN - 1996-1944

IS - 6

M1 - 1476

ER -