scholarly journals Fiber-Reinforced Composite Sandwich Structures by Co-Curing with Additive Manufactured Epoxy Lattices

2019 ◽  
Vol 3 (2) ◽  
pp. 53 ◽  
Author(s):  
Johannes Austermann ◽  
Alec J. Redmann ◽  
Vera Dahmen ◽  
Adam L. Quintanilla ◽  
Sue J. Mecham ◽  
...  

In this paper, a new process of joining additive manufactured (AM) lattice structures and carbon fiber-reinforced plastics (CFRPs) to manufacture hybrid lattice sandwich structures without secondary bonding is investigated. Multiple variations of lattice structures are designed and 3D printed using Digital Light Synthesis (DLS) and a two-stage (B-stage) epoxy resin system. The resulting lattice structures are only partially cured and subsequently thermally co-cured with pre-impregnated carbon fiber reinforcement. The mechanical properties of the additive manufactured lattice structures are characterized by compressive tests. Furthermore, the mechanical properties of hybrid lattice sandwich structures are assessed by flexural beam testing. From compressive testing of the additive manufactured lattice structures, high specific strength can be ascertained. The mechanical behavior shows these lattice structures to be suitable for use as sandwich core materials. Flexural beam testing of hybrid lattice sandwich structures shows high strength and stiffness. Furthermore, the strength of the co-cured bond interface is high enough to surpass the strength of the lattice core.

2019 ◽  
Vol 3 (3) ◽  
pp. 85 ◽  
Author(s):  
El-Ghaoui ◽  
Chatelain ◽  
Ouellet-Plamondon ◽  
Mathieu

Carbon fiber reinforced plastics (CFRP) are appreciated for their high mechanical properties and lightness. Due to their heterogeneous nature, CFRP machining remains delicate. Damages are caused on the material and early tool wear occurs. The present study aims to evaluate the effects of fillers on CFRP machinability and mechanical behavior. CFRP laminates were fabricated by the vacuum assisted resin transfer molding (VARTM) process, using a modified epoxy resin. Three fillers (organoclay, hydrocarbon wax, and wetting agent) were mixed with the resin prior to the laminate infusion. Milling tests were performed with polycrystalline diamond (PCD) tools, equipped with thermocouples on their teeth. Machinability was then studied through the cutting temperatures and forces. Tensile, flexural, and short-beam tests were carried out on all samples to investigate the effects of fillers on mechanical properties. Fillers, especially wax, allowed us to observe an improvement in machinability. The best improvement was observed with 1% wax and 2% organoclay, which allowed a significant decrease in the cutting forces and the temperatures, and no deteriorations were seen on mechanical properties. These results demonstrate that upgrades to CFRP machining through the addition of nanoclays and wax is a path to explore.


Author(s):  
Jiayu Sun ◽  
Kenta Yamanaka ◽  
Akihiko Chiba ◽  
Yuji Ichikawa ◽  
Hiroki Saito ◽  
...  

Abstract Because of their high specific strength; carbon fiber reinforced plastics (CFRPs) are widely used in the aerospace industry. Metallization of CFRP by cold spraying as a surface modification method can improve the low thermal resistance and electrical conductivity of CFRP without the need for high heat input. Herein; we cold spray a Sn coating on cured CFRP substrates and examine the Sn/epoxy interface. The results suggest that the Sn coatings are successfully obtained at a gas temperature of 473 K and indicate no severe damage to the CFRP substrates. The stress and plastic strain distributions at the cross-section of the Sn/CFRP interface when a Sn particle is impacted onto the CFRP substrate are obtained using the finite element method.


2021 ◽  
Author(s):  
MATHEW SCHEY ◽  
SCOTT STAPLETON ◽  
TIBOR BEKE

Carbon fiber reinforced plastics (CFRPs) are widely used due to their high strength to weight ratios. A common process manufacturers use to increase the strength to weight ratio is debulking. Debulking is the process of transversely compacting a dry fibrous reinforcement prior to wet out with the matrix resin, in order to induce fiber nesting, effectively increasing the volume fraction of the sample. While this process is widely understood macroscopically its effects on fibrous microstructures have not yet been well characterized. The aim of this work is to compare the microstructures of three CFRPs, varying only the debulking step in the manufacturing process. The microstructural effects of debulking on three unidirectional CFRPs made from three different levels of debulking were studied. High resolution serial sections of all three samples were taken using the UES ROBO-MET at the NASA Glenn Research Center in Cleveland, Ohio. Using these scans, the fiber positions were measured and connected to make fiber paths. Statistical descriptors such as local fiber and void volume fractions, and void distribution and morphology were then generated for each sample and compared. Using these descriptors, the effects of debulking on the composite microstructure can be measured.


Sign in / Sign up

Export Citation Format

Share Document