TY - JOUR
T1 - Influence of post-consolidation on continuous carbon-fibre reinforced additively manufactured specimens in bending
AU - Sieberer, Stefan
AU - Savandaiah, Chethan
AU - Pichler, Stefan
AU - Maurer, Julia
AU - Schagerl, Martin
N1 - Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/9/15
Y1 - 2023/9/15
N2 - Continuous carbon-fibre (CCF) additive manufacturing of composites has significant potential for production of optimised structures. However, stiffness and strength in parts are often significantly lower than manufacturer material data. For thermoset-impregnated CCF, post-consolidation of specimens has greatly increased strength. In this contribution, the effect of post-consolidation for thermoplastic CCF material is presented. Specimens were manufactured on a commercial AM CCF printer and post-consolidation was performed by rapid compression moulding. Porosity was evaluated by X-ray Computed Tomography (CT) and a significant reduction from 5.3 vol.% to 1.1 vol.% was yielded. Experimental testing is performed in four-point bending with as-printed and post-consolidated samples. Bending stiffness and strength data was obtained. The results show that the bending strength was below expectations in as-printed specimens. Finite Element Analysis indicates that snap-buckling of a small number of outer layers can lead to such a reduced apparent bending strength, and CT scans of fracture surfaces of as-printed specimens reveal the presence of interlaminar debonding. It is shown that post-consolidation highly improves the interlaminar bond, yielding experimentally obtained strength values close to nominal material strength, and the expected kink-band compressive failure is achieved.
AB - Continuous carbon-fibre (CCF) additive manufacturing of composites has significant potential for production of optimised structures. However, stiffness and strength in parts are often significantly lower than manufacturer material data. For thermoset-impregnated CCF, post-consolidation of specimens has greatly increased strength. In this contribution, the effect of post-consolidation for thermoplastic CCF material is presented. Specimens were manufactured on a commercial AM CCF printer and post-consolidation was performed by rapid compression moulding. Porosity was evaluated by X-ray Computed Tomography (CT) and a significant reduction from 5.3 vol.% to 1.1 vol.% was yielded. Experimental testing is performed in four-point bending with as-printed and post-consolidated samples. Bending stiffness and strength data was obtained. The results show that the bending strength was below expectations in as-printed specimens. Finite Element Analysis indicates that snap-buckling of a small number of outer layers can lead to such a reduced apparent bending strength, and CT scans of fracture surfaces of as-printed specimens reveal the presence of interlaminar debonding. It is shown that post-consolidation highly improves the interlaminar bond, yielding experimentally obtained strength values close to nominal material strength, and the expected kink-band compressive failure is achieved.
KW - Additive manufacturing
KW - Continuous carbon fibre
KW - Experimental bending testing
KW - Post consolidation
KW - Snap-buckling
UR - http://www.scopus.com/inward/record.url?scp=85160532431&partnerID=8YFLogxK
U2 - 10.1016/j.compstruct.2023.117176
DO - 10.1016/j.compstruct.2023.117176
M3 - Article
AN - SCOPUS:85160532431
SN - 0263-8223
VL - 320
JO - Composite Structures
JF - Composite Structures
M1 - 117176
ER -