Compression‐after‐impact properties of carbon fiber composites with interlays of Aramid pulp micro‐/nanofibers

Abstract

The inherent resin-rich ply interfaces in laminar carbon fiber reinforced polymer (CFRP) composites are toughened by ultrathin interlays formed by Aramid pulp (AP) micro-/nanofibers, to show that stronger and more impactresistant CFRP can be manufactured with minimum disruption to the current composite forming process. Flexible nonwoven AP micro-/nano-fibers, less than 1 mm in length, can conveniently fit in the uneven surface profiles or microresin-rich areas between carbon fiber plies and form in situ quasi-Zdirectional fiber-bridging across the ply interfaces. CFRPs with multiple interfacial AP interlays estimated to be around 3 and 6 g/m 2 were tested before and after low energy impact. Ultrathin resin-rich ply-interface layers in plain CFRP were transformed into ultrathin "Short Aramid Fiber Epoxy" layers by the AP interlays (20-50 μm in thickness), leading to enhanced compressive energy absorption and up to 86.7% increase in Compression-After-Impact Strength. Keeping the interlay thin (around 30 μm or thinner if possible), even the compressive strength (without impact) is not compromised, and the energy absorption under compressive loading (without impact) is 130% higher. The distinctly different compressive failure mechanisms, delamination failure of the plain CFRP was transformed into matrix shear failure in AP-toughened CFRP, as identified by nondestructive X-ray microcomputed tomography scans.Scanning electron microscopy was performed on the failure surface to inspect the microscopic toughening mechanisms.

Characteristics of compressive failure behavior of polyacrylonitrile‐based carbon fiber multifilament

“…Moreover, once the fiber/resin interface undergoes damage due to shear stresses, the carbon fiber composites endure irreparable compressive damage. [33][34][35][36] To investigate the deformation characteristics of carbon fiber multifilament composites under compressive loading, the specimens underwent cyclic loading experiments at predetermined compressive displacements with a load span of 2 mm. As depicted in Figure 3A,B, after subjecting the specimens to cyclic loading with compression displacements of 0.1 and 0.2 mm, the measured compression load-displacement curves closely matched the original compression curves at 0.1 mm displacement.…”

Crushing behavior of CFRP/AL hybrid tubes under oblique lateral loading

“…In recent years, fiber composites have received great attention due to their light weight, high strength, and high specific energy absorption. [22][23][24][25] However, the advantage of composite thin-walled tube is mainly reflected in the axial compression resistance, and its mechanical properties under lateral crushing load often do not perform satisfactorily. Data on the lateral crushing behavior of CFRP and GFRP show that the load-bearing capacity of the tubing decreases significantly with fracture failure, which means that the energy absorption efficiency of the material is very low.…”

“…In recent years, fiber composites have received great attention due to their light weight, high strength, and high specific energy absorption 22–25 . However, the advantage of composite thin‐walled tube is mainly reflected in the axial compression resistance, and its mechanical properties under lateral crushing load often do not perform satisfactorily.…”

Preparation and characterization of silk hybridizing carbon fiber/polybutylene succinate composite

“…To meet the higher and higher demand of CFRPs in industrial applications, many researchers focus on improving their toughness through various methods. Currently, the reported toughening methods mainly include: modification of carbon fibers and matrix 10–18 ; intralayer interleaving of different fibers 19–21 ; Z ‐direction toughening 22–26 ; and interlayer toughening of nonwovens and fabrics 27–30 . Interlayer toughening seems to be a simpler and more effective approach for CFRP laminates.…”

“…Currently, the reported toughening methods mainly include: modification of carbon fibers and matrix [10][11][12][13][14][15][16][17][18] ; intralayer interleaving of different fibers [19][20][21] ; Z-direction toughening [22][23][24][25][26] ; and interlayer toughening of nonwovens and fabrics. [27][28][29][30] Interlayer toughening seems to be a simpler and more effective approach for CFRP laminates. Ognibene et al 31 used insoluble veil, soluble veil, and micro carbon fiber veil to conduct interlayered toughness of carbon fiber-reinforced epoxy resin composites (CFRE); it has been observed that insoluble veil had the best toughening effect.…”