Dr. Adrian Murphy
Prof. Mark Price
Sustainable transport is the term used to describe means of transport that have a low impact on the environment. This involves using fuel-efficient systems and space-saving. The advantages of increased mobility for society must outweigh the environmental and economic costs of the transport system.
This project is based on improving the sustainability of transport using composite materials and digital manufacturing. It aims to try and establish not just an understanding of the material properties but how the materials are used in design. The use of composite materials has created lightweight structures without loss of strength being their main advantage and the reason to the increased usage. Unlike metallic’s, composites are generally designed to fail before buckling this is due to there being no allowance for additional load bearing after skin buckling. With panel composites it has been shown that they are capable of carrying further load post-buckling, therefore designers are not taking advantage of a large range of composite panel capability.
The properties of materials that have been used extensively in the past are largely documented already. However with composite materials being relatively new, a lot of their properties are not yet known. There are also a large number of variations on the types of composite materials available, depending on how the fibres are connected together. These new materials create more questions, as it is not yet understood exactly what all their properties are. In order to find and document the properties of these new materials, tests must be carried out to affirm all aspects, ideas and concepts of the new material.
Transport systems account for between 20% and 25% of world energy consumption and carbon dioxide emissions. These emissions are increasing faster than in any other energy using sector. With concern about the environment growing it is also important when looking at the new composite materials to consider the effects on the environment and the economy of using the new material. This will focus on using lighter materials in order to reduce the amount of fuel needed, etc. This applies to all kinds of transport and not just within the aerospace industry.
Paper: A Numerical Study into the Failure of Post-Buckled Laminated Composites
A Murphy, firstname.lastname@example.org
M Price, email@example.com
Composite materials have created a secure niche in the aerospace industry due to their superior specific strength and stiffness, but designers are hesitant to use them to their full potential in the post-buckling range due to uncertainty of failure mechanisms and the corresponding lack of efficient analysis methods. This research focuses on developing a finite element tool to predict failure in a laminated panel without incurring the high costs associated with three-dimensional models that predict failure modes such as delamination. The failure model takes into account compressive and tensile fibre and matrix modes, and uses the ply discount method to model material degradation. The analysis tool was validated against published experimental results for a flat stiffened panel, showing excellent correlation to the test results. It was also used to perform a number of studies on the effects of layup, aspect ratio, imperfection, and laminate thickness on the buckling and post-buckling behaviour of a flat unstiffened panel. The results from this work show that accurate post buckling models are viable and can be efficiently used in design studies providing opportunity for using fewer, larger stiffeners and consequently reducing manufacturing complexity and cost. Therefore a significant amount of material, and weight, could be reduced by opting for a post-buckling design rather than the current standard of a non-buckling panel.