Fibre Alignment and Void Assessment in Thermoplastic Carbon Fibre Reinforced Polymers Manufactured by Automated Tape Placement

Abstract

Automated Tape Placement (ATP) technology is one of the processes that is used for the production of the thermoplastic composite materials. The ATP process is complex, requiring multiple melting/crystallization cycles. In the current paper, laser-assisted ATP was used to manufacture two thermoplastic composites (IM7/PEEK and AS4/PA12). Those specimens were compared to specimens that were made of thermoset polymeric composites (IM7/8552) manufactured while using a standard autoclave cycle. In order assess the quality, void content, fibre distribution, and fibre misalignment were measured. After manufacturing, specimens from the three materials were assessed using optical microscopy and computed tomography (CT) scans. The results showed that, as compared to the thermoset composites, thermoplastics that are manufactured by the ATP have a higher amount of voids. On the other hand, manufacturing using the ATP showed an improvement in both the fibre distribution inside the matrix and the fibre misalignment.

A novel multi-scale modelling approach to predict the reduction of transverse strength due to porosity in composite materials

“…Figure 6 shows a typical stress-strain graph of a laboratory tested tensile and compressive specimen where only a minimal amount of plasticity is identified in just the compressive samples. For this reason both the void module and RUC brittle failure is assumed, in line with other literature [32]- [34]. This also means that only the linear elastic material properties (Young's modulus and Poisson's Ratio) are included in the model.…”

“…Inspection was performed using a Leica DM LM microscope with digital images captured by an iDS UI-1460LE-C-HQ camera controlled through a PC running Buehler OmniMet Modular Imaging System (OMIS) software. The images were either processed directly to measure the void dimensions through the OMIS software or to measure the void content a post-processing Python script was used to detect porous regions and subsequently calculate the void content, which is a common approach taken [31,32]. The approach converts the image to greyscale and a threshold is set such that each pixel is set either to black or white based on their greyscale value, where black pixels represent porous regions.…”

Carbonaceous Materials Coated Carbon Fibre Reinforced Polymer Matrix Composites

“…Thermoplastic matrices along with CFs have increasing significance in their application since they have a high distortion temperature [ 128 , 129 , 130 , 131 , 132 , 133 , 134 ]. The composite strength with more or less perfect continuity is often controlled by the fibre/matrix interface.…”

Void Content Determination of Carbon Fiber Reinforced Polymers: A Comparison between Destructive and Non-Destructive Methods

“…Another common cause of void content in the laminate is the entrapment of air bubbles and volatiles during lamination, particularly when using the filament winding manufacturing method. Many other factors affect the formation of voids and the quality of the composite, such as the viscosity of the resin, the temperature of the resin during manufacturing, and processing parameters such as curing cycles, pressure, and time [ 2 , 3 , 4 ].…”