A proposal for similitude in characterizing fatigue delamination behavior with fibre bridging of carbon-fibre reinforced polymer composites

Methods based on fracture mechanics have been widely used in fatigue delamination growth (FDG) characterization of composite laminates. These methods are based on the similitude hypothesis. It is therefore important to have appropriate parameters to well represent the similitude, which is useful for fatigue delamination test standard...

Hygrothermal effects on fatigue delamination behavior in composite laminates

Fatigue delamination growth (FDG) is an important failure in composite structures during their long-term operations. Hygrothermal aging can have significant effects on interlaminar resistance. It is therefore really necessary to explore FDG behavior in composite laminates with hygrothermal aging. Dynamic mechanical thermal analysis (DMTA),...

Temperature effects on fatigue delamination behavior in thermoset composite laminates

Temperature can significantly affect fatigue delamination growth (FDG) behavior in composites, while fiber bridging has been frequently reported during FDG. The focus of this study was therefore on investigating temperature effects on FDG behavior with fiber bridging. Mode I fatigue delamination experiments were conducted on a thermoset...

Interlaminar and intralaminar fracture resistance of recycled carbon fibre/PPS composites with tailored fibre/matrix adhesion

The production of advanced composites from recycled carbon fibres (rCFs) is critical for the sustainable development of carbon fibre industry. Herein, non-woven mats consisting of commingled rCFs and Polyphenylene-sulfide (PPS) fibres were compression moulded to manufacture rCF/PPS composites, with the fibre/matrix adhesion being tailored by...

Fatigue delamination behavior in composite laminates at different stress ratios and temperatures

This study provides an investigation on mode I fatigue delamination growth (FDG) with fibre bridging at different R-ratios and temperatures in carbon-fibre reinforced polymer composites. FDG experiments were first conducted at different temperatures of R-ratios 0.1 and 0.5 via unidirectional double cantilever beam (DCB) specimens. A fatigue...

In-situ damage mechanism investigation and a prediction model for delamination with fibre bridging in composites

Carbon-fibre reinforced composites are susceptible to delamination. Fibre bridging is an important shielding mechanism frequently observed in delamination. The presence of these bridging fibres can significantly increase interlaminar resistance, making it critical to represent this phenomenon for delamination characterization in composite...

Fibre-bridged fatigue delamination in multidirectional composite laminates

The influence of fibre bridging on delamination failure in multidirectional composite laminates with different thickness scales is characterized, and the dependence of fibre bridging significance on laminate thickness as well as loading regime is investigated in this paper. Both quasi-static and fatigue resistance curves (R-curve) are...

Delamination fatigue growth in polymer-matrix fibre composites: A methodology for determining the design and lifing allowables

The introduction, originally in 2009, by the FAA of a ‘slow growth’ approach to the certification of polymer-matrix fibre composites has focused attention on the experimental data and the analytical tools needed to assess the growth of delaminations under cyclic-fatigue loads. Of direct relevance is the fact that fatigue tests on aircraft...

Thickness effects on fibre-bridged fatigue delamination growth in composites

This paper provides an investigation on thickness effects on fibre-bridged fatigue delamination growth (FDG) in composite laminates. A modified Paris relation was employed to interpret experimental fatigue data. The results clearly demonstrated that both thickness and fibre bridging had negligible effects on FDG behaviors. Both energy...

Mode I fatigue delamination growth with fibre bridging in multidirectional composite laminates

Fatigue delamination in multidirectional composite laminates was experimentally investigated in present study. Both the Paris relation and a modified Paris relation (with a new similitude parameter) were employed to interpret fatigue delamination with significant fibre bridging. The results clearly demonstrated that fatigue delamination was...

Fibre bridging effect on the Paris relation for mode I fatigue delamination growth in composites with consideration of interface configuration

Fibre bridging can significantly enhance delamination resistance making the use of a single Paris resistance curve to determine fatigue crack growth insufficient. An empirical Paris-type relation has been developed in a previous study to take fibre bridging into account in fatigue delamination growth. This relation was developed by correlating...

Stress ratio dependence of fiber bridging significance in mode I fatigue delamination growth of composite laminates

This paper aims to investigate stress ratio effect on fibre bridging significance in mode I fatigue delamination growth of composite materials. Fatigue resistance curves (R-curves) of different stress ratios are determined and compared with the quasi-static R-curve. The fatigue R-curve of a high stress ratio is similar to the quasi-static...

The concept of fatigue fracture toughness in fatigue delamination growth behavior

This paper provides a study on mode I fatigue delamination growth in composite laminates using energy principles. Experimental data has been obtained from fatigue tests conducted on Double Cantilever Beam (DCB) specimens at various stress ratios. A concept of fatigue fracture toughness is proposed to interpret the stress ratio effect in crack...

Energy based study of quasi-static delamination as a low cycle fatigue process

This work proposes to treat quasi-static mode I delamination growth of CFRP as a low-cycle fatigue process. To this end, mode I quasi-static and fatigue delamination tests were performed. An average physical Strain Energy Release Rate (SERR), derived from an energy balance, is used to characterize the energy released in crack extension. The...