Fatigue behaviour of pseudo-ductile unidirectional thin-ply carbon/epoxy-glass/epoxy hybrid composites

Suwarta, P., Fotouhi, M. , Czél, G., Longana, M. and Wisnom, M. R. (2019) Fatigue behaviour of pseudo-ductile unidirectional thin-ply carbon/epoxy-glass/epoxy hybrid composites. Composite Structures, 224, 110996. (doi: 10.1016/j.compstruct.2019.110996)

Abstract

This paper is the first detailed investigation of the fatigue behavior of pseudo-ductile unidirectional (UD) thin-ply interlayer hybrids made of thin-ply carbon/epoxy plies sandwiched between standard thickness glass/epoxy plies under two scenarios: without any initial damage (pristine hybrids) and after the introduction of damage in the laminates by loading past the pseudo-yield point (overloaded hybrids). The laminates were subjected to different percentages of the critical stress level at which multiple fragmentation of the carbon plies was established (knee-point stress). The stress levels for fatigue delamination initiation and growth were evaluated experimentally. Based on the experimental work, it was observed that (1) when pristine hybrid composites were fatigued well below the carbon failure strain, at a stress level of 80% of the knee-point stress, there is no stiffness reduction after a significant number of cycles (105 cycles) (2) gradual stiffness reduction and very slow delamination growth was observed for pristine hybrid composites when fatigued at 90% of the knee-point stress, (3) when overloaded hybrid composites were fatigued at 90%, 80% and 70% of the kneepoint stress, they did not fail immediately but delaminated slowly (4) the slow growth was due to the low energy release rate of the thin-ply hybrid composites (5) the strain energy release rate approach related to delamination rates provides a good way to characterize the fatigue damage accumulation of overloaded hybrid composites and as a basis to predict the fatigue life.

• Item Type: Articles
• Additional Information: This work was funded under the UK Engineering and Physical Sciences Research Council Programme Grant EP/I02946X/1 on High Performance Ductile Composite Technology in collaboration with Imperial College, London. Putu Suwarta acknowledges The Directorate General of Higher Education of the Ministry of Education and Culture of the Republic of Indonesia (DIKTI) for funding through the DIKTI scholarship. Gergely Czél acknowledges the Hungarian National Research, Development and Innovation Office (NKFIH) for funding through grants ref. OTKA K 116070 and OTKA PD 121121, the Hungarian Academy of Sciences for funding through the János Bolyai scholarship and the Hungarian Ministry of Human Capacities (EMMI) for funding through the BME-Nanonotechnology FIKP grant (BME FIKP-NAT). The authors acknowledge Hexcel Corporation and SK Chemical for supplying materials for this research.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fotouhi, Dr Mohammad
• Authors: Suwarta, P., Fotouhi, M., Czél, G., Longana, M., and Wisnom, M. R.
• Subjects: T Technology > TA Engineering (General). Civil engineering (General)
• College/School: College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity
• Journal Name: Composite Structures
• Publisher: Elsevier
• ISSN: 0263-8223
• ISSN (Online): 1879-1085
• Published Online: 15 May 2019
• Copyright Holders: Copyright © 2019 Elsevier Ltd.
• First Published: First published in Composite Structures 224: 110996
• Publisher Policy: Reproduced in accordance with the publisher copyright policy