An experimental and finite element investigation of compression-after-impact (CAI) behaviour of biaxial carbon fibre non-crimp-fabric (NCF) based composites

2021 ◽  
pp. 115057
Author(s):  
Han Yin ◽  
Lorenzo Iannucci
Keyword(s):  
Finite Element ◽  
Carbon Fibre ◽  
Compression After Impact

scholarly journals Effect of Thermal Ageing on the Impact Damage Resistance and Tolerance of Carbon-Fibre-Reinforced Epoxy Laminates

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 160 ◽  
Author(s):  
Irene García-Moreno ◽  
Miguel Caminero ◽  
Gloria Rodríguez ◽  
Juan López-Cela
Keyword(s):  
Carbon Fibre ◽  
Residual Strength ◽  
Composite Structures ◽  
Impact Resistance ◽  
Thermal Ageing ◽  
Low Velocity Impact ◽  
Impact Tests ◽  
Compression After Impact ◽  
Structural Applications ◽  
The Impact

Composite structures are particularly vulnerable to impact, which drastically reduces their residual strength, in particular, at high temperatures. The glass-transition temperature (Tg) of a polymer is a critical factor that can modify the mechanical properties of the material, affecting its density, hardness and rigidity. In this work, the influence of thermal ageing on the low-velocity impact resistance and tolerance of composites is investigated by means of compression after impact (CAI) tests. Carbon-fibre-reinforced polymer (CFRP) laminates with a Tg of 195 °C were manufactured and subjected to thermal ageing treatments at 190 and 210 °C for 10 and 20 days. Drop-weight impact tests were carried out to determine the impact response of the different composite laminates. Compression after impact tests were performed in a non-standard CAI device in order to obtain the compression residual strength. Ultrasonic C-scanning of impacted samples were examined to assess the failure mechanisms of the different configurations as a function of temperature. It was observed that damage tolerance decreases as temperature increases. Nevertheless, a post-curing process was found at temperatures below the Tg that enhances the adhesion between matrix and fibres and improves the impact resistance. Finally, the results obtained demonstrate that temperature can cause significant changes to the impact behaviour of composites and must be taken to account when designing for structural applications.

Damage assessment of carbon fibre reinforced plastic using acoustic emission technique: experimental and numerical approach

2020 ◽  
pp. 147592172094643
Author(s):  
Claudia Barile ◽  
Caterina Casavola ◽  
Giovanni Pappalettera ◽  
Vimalathithan Paramsamy Kannan
Keyword(s):  
Finite Element ◽  
Acoustic Emission ◽  
Carbon Fibre ◽  
Crack Length ◽  
Research Work ◽  
Numerical Approach ◽  
Acoustic Energy ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Carbon Fibre Reinforced Plastic

In this research work, the acoustic emission results obtained from testing double cantilever beam specimens with carbon fibre reinforced plastic laminates are analysed. The acoustic emission descriptors such as amplitude, frequency centroid, counts, duration and risetime are clustered using k-means++ algorithm. An unconventional and innovative way of using the acoustic emission descriptors, after the clustering, is introduced. This method can favourably be used for relating the different damage progression modes in fibre reinforced plastics. Apart from this, the cumulative acoustic energy is used for predicting the crack length of the specimens. The predicted crack length is almost identical to the actual crack length opening recorded in each specimen. Finally, analytical and finite element models are used for validating the experimental results under the mode I delamination. The finite element studies are carried out using cohesive zone modelling in Comsol Multiphysics® platform.

Polyimide Composites from ‘Salt-Like’ Solution Precursors

2001 ◽  
Vol 13 (4) ◽  
pp. 235-250 ◽  
Author(s):  
Roberto J Cano ◽  
Tan H Hou ◽  
Erik S Weiser ◽  
Terry L St Clair
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibre ◽  
Compression Strength ◽  
Elevated Temperatures ◽  
Flexural Modulus ◽  
Matrix Composites ◽  
Compression After Impact ◽  
Open Hole ◽  
Polyimide Composites ◽  
Polyimide Matrix

Four NASA Langley-developed polyimide matrix resins, LaRC™-IA, LaRC™-IAX, LaRC™-8515 and LaRC™-PETI-5, were produced via a ‘salt-like’ process developed by Unitika Ltd. The salt-like solutions (65% solids in NMP) were prepregged onto Hexcel IM7 carbon fibre using the NASA LaRC™ multipurpose tape machine. Process parameters were determined and composite panels fabricated. The temperature dependent volatile depletion rates, the thermal crystallization behaviour and the resin rheology were characterized. Composite moulding cycles were developed which consistently yielded well consolidated, void-free laminated parts. Composite mechanical properties such as the short beam shear strength; the longitudinal and transverse flexural strength and flexural modulus; the longitudinal compression strength and modulus; and the open hole compression strength and compression after impact strength were measured at room temperature and elevated temperatures. The processing characteristics and the composite mechanical properties of the four intermediate modulus carbon fibre/polyimide matrix composites were compared to existing data on the same polyimide resin systems and IM7 carbon fibre manufactured via poly(amide acid) solutions (30–35% solids in NMP). This work studies the effects of varying the synthetic route on the processing and mechanical properties of the polyimide composites.

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