Fibre waviness defects in composite structures

Lead Research Organisation: University of Cambridge
Department Name: Engineering


Composites are now widely used in a wide range of applications. In the wind turbine and aerospace sectors recent innovations, including larger and more sophisticated structures, have driven the need for better understanding of failure of composite structures. Use of lower-cost process routes requires a need for better understanding of the inevitable defects in such composite structures. Failure of well-controlled flat composite panels is now generally well understood. However real manufactured components contain a range of stress concentrators, some associated with relatively controlled features such as joints, ply drops, sandwich panel closures and holes, some more uncertain associated with defects including fibre waviness, resin-rich areas and gaps at sandwich core breaks. The aim of the project is to understand and model how such defects affect the strength of the structure.The project has three main strands: (i) characterising realistic defects in industrial components and in controlled laboratory specimens, (ii) identifying mechanisms of compressive failure under fatigue loading and developing predictive models for failure at waviness defects, validated with experiments, (iii) modelling of defect formation during processing. Case studies suggested by industrial partners Dowty and Vestas of a propeller and a wind turbine blade will be used. The models will be incorporated into software tools, in collaboration with Simulayt Ltd, for use in design.


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Lemanski S (2013) Modelling failure of composite specimens with defects under compression loading in Composites Part A: Applied Science and Manufacturing

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Lemanski S (2012) Compressive failure of finite size unidirectional composite laminates with a region of fibre waviness in Composites Part A: Applied Science and Manufacturing

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Sutcliffe M (2012) Measurement of fibre waviness in industrial composite components in Composites Science and Technology

Description - Measurement of fibre waviness
- role of fibre waviness in compressive strength
Exploitation Route Understanding of role of waviness in manufacturing and modelling
Sectors Manufacturing, including Industrial Biotechology