Abstract The work presented in this article is directed towards the application of CFRP foam core sandwich structures as primary structures in commercial aviation. With closed cell rigid foams, it is possible to produce comparatively low priced high-integral sandwich components having a complex geometry in terms of a curved and a variable lateral cut. Sandwich structures are offering a good bending stiffness and strength to weight ratio. Thus, they are suited for using in structures which are at risk to fail by buckling (Herrmann et al. Sandwich structures 7: advancing with sandwich structures and materials, 2005). The investigations are focused on a CFRP sandwich structure with polymethacrylimide (PMI) foam core, named $ ROHACELL^{®} $RIST. Besides good structural stability at thermal conditions, the foam is characterized by a good strength and stiffness to weight ratio (Seibert, Reinforced Plast 50(1):44–48, 2006). Primary structures in aircraft applications are exposed to a superposition of in-service loads and environmental conditions. The typical working loads in combination with environmental conditions were investigated. The structure needs a sizing with respect to large temperature changes and influences of humidity. Thus, the time, temperature, and moisture dependency of the mechanical behavior were studied for the single components of the structure and for the composite itself. Therefore, Finite Element Models on macroscopic level were built with reference to the experiments. For each in-service case, the residual stresses arising during manufacturing have to be regarded and quantified (John et al. ECCM14, 2010). During manufacturing, the sandwich structure is cured at 180°C. Due to the different stiffnesses and coefficients of thermal expansion of the foam and the CFRP face sheets, residual stresses are induced by cooling down to service temperature. Among others, some tests were made at laterally closed CFRP sandwich structures with a storage time up to half a year at certain climate conditions. The aging process is not only controlled by external conditions, but also by a rearrangement of molecules, for example, the relaxation behavior of the PMI foam (Gutwinski et al. Verbundwerkstoffe. Wiley, Weinheim, 2009). Another question of the long-term behavior of the CFRP foam core sandwich structure is the characteristic of delamination of the face sheets from the inner core after an impact has occurred. To describe the crack growth behavior of the sandwich structure fracture mechanical principles can be used estimating the damage tolerance. Sandwich specimens with initial damage were loaded up to 3 million mechanical load cycles.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Long-term durability of CFRP foam core sandwich structures


    Beteiligte:
    John, M. (Autor:in) / Schlimper, R. (Autor:in) / Rinker, M. (Autor:in) / Wagner, T. (Autor:in) / Roth, A. (Autor:in) / Schäuble, R. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    2011




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch



    Klassifikation :

    BKL:    50.03 Methoden und Techniken der Ingenieurwissenschaften / 50.03 Methoden und Techniken der Ingenieurwissenschaften, Methoden und Techniken der Ingenieurwissenschaften / 55.50 Luftfahrzeugtechnik / 55.50 Luftfahrzeugtechnik, Luftfahrzeugtechnik
    DDC:    629.105



    Long-term durability of CFRP foam core sandwich structures

    John, M. / Schlimper, R. / Rinker, M. et al. | Springer Verlag | 2011


    A new crushable foam model for polymer-foam core sandwich structures

    Tong, Xiaolong / Hoo Fatt, Michelle S. / Vedire, Anudeep Reddy | Taylor & Francis Verlag | 2022


    Lightweight Structures Based on CFRP Sandwich Struts and CFRP Connections

    Schuetze, R. / European Space Agency / European Space Research and Technology Centry | British Library Conference Proceedings | 1994


    Long-Term Durability Study: Long-Span Structures

    Hensley, Scott I. / Perry, Phil | Transportation Research Record | 2000


    An approach to high precision antenna structures by a CFRP core sandwich concept

    Alonso, A. / Cuadrado, A. / Bonet, A. et al. | British Library Online Contents | 1992