One example of rod-reinforced advanced composite structures is the rodpack hat stringer developed for tiltrotor wing applications. Previous rodpack hat stringer compression tests indicated that the initial failure mode involves the skin buckling away from the hat. A possible source of this buckling instability is a delamination growing from the free edge of the flange. Hat stringer pull-off tests were performed to evaluate the delamination failure mechanisms in the flange region for a rod-reinforced hat stringer section. A special test fixture was used to pull the hat off the stringer while reacting the pull-off load through roller supports at both stringer flanges. Microscopic examinations of the failed specimens revealed that failure occurred at the ply termination in the flange area where the flange of the stiffener is built up by adding 45/-45 tape plies on the top surface. Test results indicated that the as-manufactured microstructure in the flange region has a strong influence on the delamination initiation and the associated pull-off loads. Finite element models were created for each specimen with a detailed mesh based on micrographs of the critical location. A fracture machanics approach and a mixed mode delamination criterion were used to predict the onset of delamination and the pull-off load. By modeling the critical local details od each specimen from micrographs, the model was able to accurately predict the hat stringer pull-off loads and replicate the variability in the test results.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Test and analysis of composite hat stringer pull-off test specimens


    Additional title:

    Test und Analyse von Verbundträger-Zugproben


    Contributors:
    Li, J. (author) / O'Brien, T.K. (author) / Rousseau, C.Q. (author)

    Published in:

    Publication date :

    1997


    Size :

    8 Seiten, 17 Bilder, 1 Tabelle, 10 Quellen




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English





    Composite material cap-shaped stringer pull-off test device and test method

    CHEN ZHEN / PAN ZHIFANG / CHENG YIQING et al. | European Patent Office | 2022

    Free access

    Stringer stiffened composite panels having improved pull-off strength

    BEHZADPOUR FOROUZAN / CHENG JIANGTIAN | European Patent Office | 2020

    Free access

    STRINGER STIFFENED COMPOSITE PANELS HAVING IMPROVED PULL-OFF STRENGTH

    BEHZADPOUR FOROUZAN / CHENG JIANGTIAN | European Patent Office | 2019

    Free access

    STRINGER STIFFENED COMPOSITE PANELS HAVING IMPROVED PULL-OFF STRENGTH

    BEHZADPOUR FOROUZAN / CHENG JIANGTIAN | European Patent Office | 2023

    Free access