Experimental assessment of temperature effect on open-hole notch sensitivity in woven carbon fiber composites
- PDF / 3,281,289 Bytes
- 18 Pages / 595.276 x 790.866 pts Page_size
- 6 Downloads / 168 Views
O R I G I NA L
Mostafa Elyoussef · Wael Abuzaid · Maen Alkhader
Experimental assessment of temperature effect on open-hole notch sensitivity in woven carbon fiber composites
Received: 5 March 2020 / Accepted: 15 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Composite laminates often comprise notch-like features such as drilled assembly holes or geometric discontinuities resulting from damage. These features induce stress concentrations in their vicinities and can, through incompletely understood temperature-dependent damage mechanisms, reduce laminates’ load carrying capacity. Accordingly, this work investigates the effect of elevated temperatures on the notch sensitivity of carbon fiber-reinforced polymer composites and on the initiation and progression of notch-triggered damage mechanisms. This work employs an experimental approach in which tensile notched and un-notched specimens are loaded in controlled temperatures. Specimens are tested at multiple temperatures, and their nominal and local behavior in the vicinity of a circular notch are observed using digital image correlation. Results demonstrated a decreasing trend in the elastic moduli and ultimate tensile strength of notched specimens with increasing temperatures. However, the global response of notched samples at 50 ◦ C surprisingly deviated from the expected trend and exhibited 8% higher tensile strength than that observed at 25 ◦ C. Moreover, the notch sensitivity was found to decrease with increasing temperatures. Two main temperature-sensitive notchtriggered damage mechanisms were observed, namely transverse cracks and axial splitting. Transverse cracks were evident at all considered temperatures, while axial splitting was absent at room temperature. Keywords Notch sensitivity · CFRP composites · Temperature effects · Digital image correlation · Damage mechanisms
1 Introduction Carbon fiber-reinforced polymer (CFRP) composites have been developed as practical replacements for metallic materials in load-bearing components used in structural, marine, automotive, aerospace, and energy applications [1,2]. The transition toward CFRP composites is often driven by realizing weight savings as this class of materials offers significantly higher stiffness and strength-to-weight ratios as compared to metals [1,3]. However, CFRP composites lack the ductility and the work hardening capacity offered by metals, and they have a propensity to fail in a brittle manner [2]. CFRP composites’ brittle nature renders them sensitive to notches, which often result from inadvertent loadings or activities (i.e., defects) as well as from joining processes (e.g., holes introduced to form connections [4]). Notches can act as discontinuities that induce stress concentrations in their vicinity which would consequently reduce the load carrying capacity through a range of complex mechanisms [5]. These can be triggered by the interaction of the local stress gradients accompanying notch-induced stress concentrations with heterogeneities inheren
Data Loading...
