Preparation of carbon fiber powder-coated Z-pins and experimental study on the mode I delamination toughening properties

Abstract

In order to improve the adhesion property between the z‐pin and laminate, carbon fiber powder coating technique for z‐pins were developed. Four types of coating materials, 1 mm short chopped carbon fiber (CS), 50 mesh carbon fiber powder z‐pins (CF), 400 mesh carbon fiber powder (CP), and carbon nanotubes (CN), were coated on an impregnated fiber bundle before the curing of the resin of the z‐pins. The diameters of the four types of coated z‐pins were increased from 0.50 to 0.61 mm, 0.57 mm, 0.58 mm, and 0.54 mm, separately. To characterize the adhesion property of the z‐pin/laminate, single z‐pin pull‐out tests were conducted. The results indicated that carbon fiber powder coating could improve the interfacial adhesion property of the z‐pin/laminate effectively. The interfacial shear strength was increased around 1/3. CS, CF, and CP improved the mechanical interlock and bridging effect of the interface, while CN enhanced the adhesion effect of the reinforcing mode. To examine the interlaminar performance of the reinforced laminate, we also conducted double cantilever beam tests. It was found that the coated z‐pin, which was related to better interfacial adhesion property, corresponded to higher mode I interlaminar fracture toughness of z‐pinned laminates. POLYM. COMPOS., 37:3508–3515, 2016. © 2015 Society of Plastics Engineers

Short-beam shear of nanoprepreg/nanostitched three-dimensional carbon/epoxy multiwall carbon nanotube composites

“…16 Another study showed that the carbon fiber-coated z-pin composite enhanced mode-I failure due to bonding between the z-pin and composite. 17…”

“…16 Another study showed that the carbon fiber-coated z-pin composite enhanced mode-I failure due to bonding between the z-pin and composite. 17 The short-beam shear fracture properties of 2D nonwoven composite were studied via converted v-notched rail shear test. It was concluded that micro-crack, coupling crack and macro-crack were identified.…”

An advanced self‐lubricating ceramic composite with the addition of core‐shell structured CaF2@Al2O3 powders

“…CaF 2 is one of the solid lubricants, and an excellent high temperature lubricating powder . Through the powder surface coating, the uniform mixing of CaF 2 particles with different phase particles can be achieved, which can effectively improve the material properties and give it new physical, chemical and other special functions through coating …”

Influence of Z-pin embedded length on the interlaminar traction response of multi-directional composite laminates

“…The traction response of a Z-pin in a delaminated composite material when loaded in mode I is influenced by four parameters; the pin and the bond strength with the matrix, the frictional contact between the pin and the host material, the elastic modulus and the tensile strength of the pin if pull-out does not occur and pin fracture [6]. The bond strength and the subsequent frictional pull-out is a function of the pin embedded length in the material and its surface condition such as roughness [4,7,11,12]. The residual stresses in the host and the pin material due to manufacturing conditions also play a significant role in its response, which is particularly evident between composite laminates with unidirectional (UD) or multi-directional laminates [4,13].…”