Experimental and Numerical Investigation on the Axial Crushing of Fibre Metal Laminate Top Hat Structures

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Copyright: Subbaramaiah, Ravishankar
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Abstract
This thesis explores the use of Fibre Metal Laminate (FML) for crashworthy application by investigating its axial crushing response. A progressive and stable crushing pattern is an essential crushing characteristic for an energy absorbing structure. External aluminium layers of FML make the hybrid material compatible for reinforcing aged aircraft structures, while the glass-epoxy composite layers of FML aid in enhancing strength and reducing overall weight. Through this research, I have made the following contributions: a) axial crushing response of FML has been documented for the first time and the results have proven to be superior to its constituents; b) a predictable integrated tool to estimate the crashworthiness of FML has been established numerically, based on the experimental data; c) a building block approach was proposed and validated through the integration of experimentally tested material properties into the material model; and, d) the developed numerical tool was extended to other applications such as rubber pad forming of FML with an experimental demonstration. This research was part of a collaborative research project including the Cooperative Research Centre for Advanced Composite Structures (CRC-ACS) and the University of New South Wales (UNSW). The investigated specimen was a top hat structure which could be envisaged as a stiffening member for existing structure or as a single unit of repeating pattern of the corrugated beam. The explicit finite element analysis simulations using LS-Dyna accurately predicted the crushing response of experimentally tested top hat structures. First, numerical approach investigated the influence of various geometrical, material and simulation parameters on the crushing response of mono-material. Later the crushing response of FML was successfully predicted by combining the modelling techniques of individual materials. Most importantly the crushing response of FML top hat structures was found to be progressive and stable. The failure modes of FML were hybrid due to its laminate nature with composite included. The specific energy absorption was higher than either of its mono-material equivalents. Rubber pad forming (RPF) was found to be feasible technique to form the top hat structure, this forming process maintained the integrity of FML. Simulations played a vital role in establishing the RPF and in achieving the required shape with minimum spring back.
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Author(s)
Subbaramaiah, Ravishankar
Supervisor(s)
Prusty, Gangadhara
Pearce, Garth Morgan Kendall
Kelly, Donald Wainwright
Thomson, Rodney
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Publication Year
2018
Resource Type
Thesis
Degree Type
PhD Doctorate
UNSW Faculty
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