Experimental and Numerical Study of Vacuum Resin Infusion of Stiffened Carbon Fiber Reinforced Panels

Liquid resin infusion processes are becoming attractive for aeronautic applications as an alternative to conventional autoclave-based processes. They still present several challenges, which can be faced only with an accurate simulation able to optimize the process parameters and to replace traditional time-consuming trial-and-error procedures. This paper presents an experimentally validated model to simulate the resin infusion process of an aeronautical component by accounting for the anisotropic permeability of the reinforcement and the chemophysical and rheological changes in the crosslinking resin. The input parameters of the model have been experimentally determined. The experimental work has been devoted to the study of the curing kinetics and chemorheological behavior of the thermosetting epoxy matrix and to the determination of both the in-plane and out-of-plane permeability of two carbon fiber preforms using an ultrasonic-based method, recently developed by the authors. The numerical simulation of the resin infusion process involved the modeling of the resin flow through the reinforcement, the heat exchange in the part and within the mold, and the crosslinking reaction of the resin. The time necessary to fill the component has been measured by an optical fiber-based equipment and compared with the simulation results.

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Out-Of-Plane Permeability Evaluation of Carbon Fiber Preforms by Ultrasonic Wave Propagation

Materials ◽

10.3390/ma13122684 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2684 ◽

Cited By ~ 1

Author(s):

Francesca Lionetto ◽

Francesco Montagna ◽

Alfonso Maffezzoli

Keyword(s):

Wave Propagation ◽

Carbon Fiber ◽

Ultrasonic Wave ◽

Ultrasonic Transducer ◽

Gravimetric Method ◽

Ultrasonic Waves ◽

Ultrasonic Wave Propagation ◽

Out Of Plane ◽

Set Up ◽

Fiber Preforms

Out-of-plane permeability of reinforcement preforms is of crucial importance in the infusion of large and thick composite panels, but so far, there are no standard experimental methods for its determination. In this work, an experimental set-up for the measurement of unsaturated through thickness permeability based on the ultrasonic wave propagation in pulse echo mode is presented. A single ultrasonic transducer, working both as emitter and receiver of ultrasonic waves, was used to monitor the through thickness flow front during a vacuum assisted resin infusion experiment. The set-up was tested on three thick carbon fiber preforms, obtained by stacking thermal bonding of balanced or unidirectional plies either by automated fiber placement either by hand lay-up of unidirectional plies. The ultrasonic data were used to calculate unsaturated out-of-plane permeability using Darcy’s law. The permeability results were compared with saturated out-of-plane permeability, determined by a traditional gravimetric method, and validated by some analytical models. The results demonstrated the feasibility and potential of the proposed set-up for permeability measurements thanks to its noninvasive character and the one-side access.

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Out of plane crushing and local stiffness determination of proposed foam filled sandwich panel for Korean Tilting Train eXpress – Numerical study

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2014.07.037 ◽

2015 ◽

Vol 66 ◽

pp. 400-411 ◽

Cited By ~ 44

Author(s):

Hozhabr Mozafari ◽

Soroush Khatami ◽

Habibollah Molatefi

Keyword(s):

Sandwich Panel ◽

Numerical Study ◽

Out Of Plane ◽

Foam Filled ◽

Tilting Train ◽

Local Stiffness

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Anisotropy of Nanoindentation – a tool for the determination of nanocrystal orientation ?

MRS Proceedings ◽

10.1557/proc-779-w5.14 ◽

2003 ◽

Vol 779 ◽

Author(s):

David Christopher ◽

Steven Kenny ◽

Roger Smith ◽

Asta Richter ◽

Bodo Wolf ◽

...

Keyword(s):

Crystal Surface ◽

Scanning Force Microscopy ◽

Depth Range ◽

Dislocation Loops ◽

Force Microscopy ◽

Pile Up ◽

Out Of Plane ◽

Scanning Force ◽

Dynamics Simulations

AbstractThe pile up patterns arising in nanoindentation are shown to be indicative of the sample crystal symmetry. To explain and interpret these patterns, complementary molecular dynamics simulations and experiments have been performed to determine the atomistic mechanisms of the nanoindentation process in single crystal Fe{110}. The simulations show that dislocation loops start from the tip and end on the crystal surface propagating outwards along the four in-plane <111> directions. These loops carry material away from the indenter and form bumps on the surface along these directions separated from the piled-up material around the indenter hole. Atoms also move in the two out-of-plane <111> directions causing propagation of subsurface defects and pile-up around the hole. This finding is confirmed by scanning force microscopy mapping of the imprint, the piling-up pattern proving a suitable indicator of the surface crystallography. Experimental force-depth curves over the depth range of a few nanometers do not appear smooth and show distinct pop-ins. On the sub-nanometer scale these pop-ins are also visible in the simulation curves and occur as a result of the initiation of the dislocation loops from the tip.

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