A Through-Thickness Reinforcement Repair technique has been developed to repair delaminated CFRP composite laminates. This involves drilling 1 mm holes within the delaminated region in concentric rings, into which stainless steel M1 machine screws are adhesively bonded. A simplified finite element technique, based on observed failure modes, was developed in order to rank candidate configurations. This does not predict the delamination propagation load but it does give a measure of the relative propensity of a particular configuration towards delamination growth. Experimental and finite element studies were conducted to assess the effectiveness of the technique to restore the compression strength of delaminated panels. The configurations examined included an 8-pin 1- ring, an 18-pin 2-ring and a 28-pin 3-ring configuration with equal-distant spacing between the rings. It was found that the controlled 50 mm circular delamination reduced the compression strength of the panels to 68% that of the undamaged specimens. The TTRR (Through-Thickness Reinforcement Repair) technique was found to be highly effective in restoring compression strength by providing buckling resistance to the delaminated region. The 8-pin 1-ring repair configuration restored the compression strength of the delaminated panels to 93% that of the undamaged specimens. The higher density pinning configurations were shown, both theoretically and experimentally, not to provide any additional benefits. There was good qualitative agreement between the experimental and numerical results, indicating that the simplified finite element model may be used to optimise the number and location of the through-thickness repair pins. The TTRR could be used as a highly effective depot-level repair technique for composite aircraft components. However, its utility as a rapid on-the-spot field repair technique requires development of methods and tooling for the manual in-situ drilling of small diameter holes in composite aircraft components. Alternately the pin diameters must be increased. The efficacy of repairs with larger diameter pins is the subject of further research.


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    Title :

    Finite element analysis for through thickness reinforcement repair of delaminated carbon-epoxy panels


    Additional title:

    Finite-Elemente-Analyse für eine durchgängige Dickenverstärkungsreparatur von Kohlenstoff-Epoxidharz-Paneelen mit Schichtablösung


    Contributors:


    Publication date :

    2006


    Size :

    8 Seiten, 7 Bilder, 2 Tabellen, 9 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    FINITE ELEMENT ANALYSIS FOR THROUGH THICKNESS REINFORCEMENT REPAIR OF DELAMINATED CARBON-EPOXY PANELS

    Li, H. C. H. / Chou, H.-Y. / Callus, P. J. et al. | British Library Conference Proceedings | 2006



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