Investigation of composite repair method by liquid resin infiltration

Abstract

Conventional' or certified repair procedures for impacted composite structures (i.e. patches) are time consuming, and must be performed by highly qualified staff. In this paper, a cost effective and simple repair method by liquid resin infiltration is studied. As damages on aircraft structures are generally due to impact, this kind of damage is characterised and compared to quasi-static indentation with ultrasonic inspection and micrographic cuts. The repair by liquid resin is used to fill in the very special damage pattern region organised as a crack network (delamination and transverse cracks). In order to study this new repair method, an experimental set-up has been manufactured and different configurations have been studied. Mechanical testing (CAI, DCB and ENF) was then performed to evaluate the strength of this repair. As good results were achieved, further exploration under complex loading should be performed to ensure the quality of the repair for an industrial application.

Void‐Free Layered Polymeric Architectures via Capillary‐Action of Nanoporous Films

“…Given that the NPN comprises aligned nanofibers and has D f ≅ 7.8 nm and ε ≅ 0.94 (see the Experimental Section), the capillary pressure P cn of ≈1 MPa is estimated. In addition, σ ≅ 35 mJ m −1 and θ ≅ 20° were used based on known values for similar epoxy system . As a consequence, a sufficient pressure gradient (relative to the autoclave) toward the interlaminar region (Δ P ≈ 1.1 MPa) is achieved, which is in excess of the autoclave process (Δ P ≈ 0.7 MPa).…”

“…In addition, σ ≅ 35 mJ m −1 and θ ≅ 20° were used based on known values for similar epoxy system. [84][85][86] As a consequence, a sufficient pressure gradient (relative to the autoclave) toward the interlaminar region (ΔP ≈ 1.1 MPa) is achieved, which is in excess of the autoclave process (ΔP ≈ 0.7 MPa). This high pressure gradient due to NPN capillarity leads to full resin impregnation (full void suppression) at the interlaminar regions such that there are no detectable interlaminar voids.…”

BEM computation of 3D Stokes flow including moving front

“…(26), where the surface tension of canola oil is γ = 32.10 − 3 Nm − 1 [44], the viscosity of canola oil is given in Table 2, and θ is the contact angle between the fluid (canola oil) and solid (steel). This angle depends on the surface roughness and its value is around 83° [45]:…”

Repair Delaminations in Carbon/epoxy Laminates

“…The resin injection repair is also regarded as a temporary measure to prevent the spread of damage until further maintenance can be performed [5,6]. For this purpose, the novel cyanoacrylates bring significant benefits due to the very low viscosity at room temperature and relatively high glass transition temperature [6,7].…”