Study of the Mode I and Mode II interlaminar behaviour of a carbon fabric reinforced thermoplastic

Abstract

A delamination or an interlaminar failure is a critical failure mechanism for fibrereinforced composites and, therefore, has already been studied extensively by many researchers. However, it remains an actual research topic, since every day, new polymers with better mechanical properties are being developed for fibre reinforced composites. This manuscript describes an experimental study of both the Mode I and Mode II interlaminar behaviour of a 5-harness satin weave carbon fabric reinforced polyphenylene sulphide (PPS). The mode I crack growth is studied using the Double Cantilever Beam (DCB) setup, whereas the mode II behaviour was studied by the End Notch Flexure (ENF) test. For mode I, an unstable crack-growth was seen resulting in a saw-tooth like force-displacement curve. Therefore, a model based on Linear Elastic Fracture Mechanics was considered to determine G IC for both initiation and propagation. Furthermore, the effect of possible fibre-bridging was assessed and an online microscopic study was conducted so that the origin of the specific jumps in crack growth could be determined. For mode II, stable crack propagation occurred and the Compliance-Based Beam Method was used to determine G IIC for both initiation and propagation. It could be concluded that the considered approach worked well for this material and reproducible results and values were found.

Assessment of the interlaminar behaviour of a carbon fabric reinforced thermoplastic lap shear specimen under quasi-static and tension-tension fatigue loading

“…To the authors' best knowledge, an extensive study of the benchmark lap shear experiments both under quasi-static and tension-tension fatigue, has yet not been published or assessed in open literature for continuous fibre reinforced thermoplastics. The results within this paper, together with the Mode I and Mode II results, published in [2] should provide an interesting benchmark for comparing (fatigue) data from fusion bonded joints between the carbon reinforced PPS, either by the already mentioned infrared welding, but also for other processes such as for example ultrasonic, induction welding or resistance welding [19].…”

“…A first paper was already published on the optimization of the welding parameters of this infrared welding [1], where the results of single lapshear experiments were used for the assessment of quality and reproducibility of the joints. A second study was conducted in order to determine the interlaminar behaviour under pure mode I, using the double cantilever beam test, and pure mode II, using the end notch flexure test, loading conditions [2]; values for G I and G II were also determined, both for initiation and propagation. This study was done in order to obtain a benchmark for the welded joints to be compared with.…”

Multiscale Polymer Composites: A Review of the Interlaminar Fracture Toughness Improvement

“…Thermoplastic composites possess comparatively higher interlaminar fracture toughness, G1C, with at least one order higher than thermoset composites [67]. Friedrich et al investigated the comparative fracture toughness Mode I and Mode II performance of carbon …”

“…Although such modifiers have been proved effective, they cause deleterious effects on other properties like strength, modulus, and glass transition temperature (T g ), a detailed discussion and reviews are presented in a number of papers [64][65][66]. Thermoplastic composites possess comparatively higher interlaminar fracture toughness, G 1C , with at least one order higher than thermoset composites [67]. Friedrich et al investigated the comparative fracture toughness Mode I and Mode II performance of carbon fiber-epoxy and thermoplastic polyether ether ketone (PEEK), and it was highlighted that G 1C and G 2C were around ten times higher in the case of CF/PEEK [68].…”

Antiplane–inplane shear mode delamination between two second-order shear deformable composite plates

“…[14,15]) and changes the dynamic properties significantly, and therefore has a major influence on the lifetime of the structure. The delamination behavior of composite materials is characterized by different specimens for mode-I [16][17][18][19][20][21][22][23], mode-II [24][25][26], mixed-mode I/II [27][28][29][30][31][32][33][34][35][36][37], mode-III [38][39][40][41][42][43][44][45][46][47][48], mixed-mode I/III [49] mixed-mode II/III [42,[50][51][52][53][54][55][56][57][58][59] and mixed-mode I/II/III [60][61]…”