Enhanced fracture toughness of nanostructured carbon-fiber reinforced poly(urethane-isocyanurate) composites at low concentrations

2017 ◽  
Vol 58 (8) ◽  
pp. 1241-1250 ◽  
Author(s):  
Leonel M. Chiacchiarelli ◽  
Roberto Petrucci ◽  
Luigi Torre
2021 ◽  
pp. 089270572110214
Author(s):  
Weiller M Lamin ◽  
Flávio LS Bussamra ◽  
Rafael TL Ferreira ◽  
Rita CM Sales ◽  
José E Baldo

This work presents the experimental determination of fracture mechanics parameters of composite specimens manufactured by fused filament fabrication (FFF) with continuous carbon fiber reinforced thermoplastic filaments, based on Linear Elastic Fracture Mechanics (LEFM). The critical mode I translaminar fracture toughness (KIc) and the critical energy release rate (GIc) are found for unidirectional and cross-ply laminates. The specimens were submitted to quasi-static tensile testing. Digital Image Correlation (DIC) is used to find the stress field. The stress fields around the crack tip are compared to linear elastic finite element simulations. The results demonstrate the magnitude of fracture toughness is in the same range as for polymers and some metals, depending on lay-up configuration. Besides, fractographic analyses show some typical features as river lines, fiber impression, fiber pulls-out and porosity aspects.


Author(s):  
Hiroki Ota ◽  
Kristine Munk Jespersen ◽  
Kei Saito ◽  
Keita Wada ◽  
Kazuki Okamoto ◽  
...  

Abstract In recent years, for the aim of weight reduction of transportation equipment, carbon fiber reinforced thermoplastics (CFRTPs), which have high recyclability and formability, are becoming suitable for mass production. Additionally, with the development of multi-material structures, excellent technologies for joining metal and CFRTPs are required. In present industry, joining between dissimilar materials include adhesive bonding and mechanical joining methods, however, these methods still have some problems, and therefore an alternative bonding method without adhesive and mechanical joining is required for joining CFRTPs and metals. Thus, this study focused on direct bonding between CFRTP and an aluminum alloy, by producing a nanostructure on the surface of the aluminum alloy. The nanostructure penetrates the CFRTP matrix causing an anchoring effect, which results in significant bonding strength improvement. The influence of the nanostructure on the fracture toughness for the directly bonded CFRTP and aluminum was evaluated by static double cantilever beam (DCB) testing. Due to the difference of the thermal expansion coefficients between the CFRTP laminates and the aluminum alloy, significant residual stresses are generated. The effect of the thermal residual stresses on the fracture toughness along with the resulting mode mixity (mode I and II) was calculated. It is found that the thermal stresses introduce a significant mode mixity of the fracture toughness.


2016 ◽  
Vol 713 ◽  
pp. 325-328 ◽  
Author(s):  
Sandip Haldar ◽  
Claudio S. Lopes ◽  
Carlos Gonzalez

Interlaminar and intralaminar fracture behavior of carbon fiber reinforced composites have been experimentally studied. Unidirectional, woven reinforcement and thermoplastic and thermoset polymer matrix laminates have been characterized using double cantilever beam (DCB) and end notch flexure (ENF) specimens for Mode-I and Mode-II fracture toughness, respectively and compact tension (CT) specimens for intralaminar fracture. AS4/PEEK, AS4/8552 and AGP193PW/8552 laminates have been characterized in this study. The fracture toughness determined from the experimental data could be related to the constituents and reinforcements. It has been observed between the two UD laminates, AS4/PEEK exhibit higher fracture resistance under both interlaminar and intralaminar fracture. Woven reinforcement is found to show higher mode-II interlaminar fracture toughness.


2013 ◽  
Vol 35 (3) ◽  
pp. 482-488 ◽  
Author(s):  
WenBo Liu ◽  
Shu Zhang ◽  
Bichen Li ◽  
Fan Yang ◽  
WeiCheng Jiao ◽  
...  

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