The Composites UTC is a research centre supported by Rolls-Royce plc to provide a validated analysis capability for the mechanical response of composites that can be used to design composite components. It aims to act as a focus for composites research activities, liaising with other universities to provide a coordinated programme to meet the needs of Rolls-Royce. A series of case studies are given below to give examples of the type of work that the UTC is involved in.
As well as the core research programme there are a number of PhD students supported by Rolls-Royce and several other research programmes in which Rolls-Royce is a collaborating partner. These are listed below.
Jamie Blanchfield (PhD) - Unified Nonlinear Damage Model for Fatigue Delamination Onset and Growth in FRPs
Luca Boldrin (PhD) - Reduction of Vibration Levels in Blades Using Novel Materials and Structures
Delphine Carrella-Payan (PhD) - Layer-wise finite element formulation of ply-drops for moderately thick composite panel
Georgia Charalambous (PhD) - Fatigue Laws for Fatigue scaling laws for composites fan blades
Khong-Wui Gan (PhD) - Complex Loading of Composites with Stress Concentrations
Steve Green (PhD) - Numerical modelling of 3D woven preform deformations
Salah Muflahi (PhD) - Simple Tools for Impact Assessment
Supratik Mukhopadhyay (PhD) - Analysis of defects arising from advanced composites manufacturing techniques
Damien Pain (PhD) - Detection and Quantification of Fibre Waviness in Composites Using Ultrasonic Arrays
Bing Zhang (PhD) - Smart through-thickness reinforcement of composite laminates
Dr Chuan (Luby) Li (Research Associate) - Enhanced Ultrasonic 3D Characterisation of Composites Using Full Matrix Capture
Dr Cristian Lira (Research Assistant) - Probabilistic Assessment of Fatigue Delamination Growth in Fibre Reinforced Composite Laminates
Dr Yan Liu (Visiting Researcher) - Follow up Dynamic properties of nanoparticle modified polymer composite materials
Robert Malkin (PhD) - Extreme Damage Tolerant Hierarchical Composite Structures
Adam Pickard (PhD) - Experimental Vibration for High Cycle Fatigue – Non Linearity
Daniel Thompson (PhD) - Damage Modelling and Prognosis in Composites Materials
A highly complex specimen, representative of a typical composite dove-tail joint, has been designed, manufactured and tested. This has been both an exercise to understand the nature of the failure mechanisms and behaviour and to validate finite element models. The specimen, produced from unidirectional carbon fibre/epoxy pre-preg, reduces down from 147 plies at the thick end to 45 plies at the thin end. The manufacture of the specimens was in itself a complex task, with great care being taken to ensure the accuracy of the terminated ply placement and specimen symmetry. The finite element model used was a ply-by-ply representation of the layup with cohesive interface elements between each ply to be able to capture the delamination failure mode. Results show the close working of numerical modelling and experimental testing to better understand and predict the failure of a complex specimen which in turn will improve future component design.
The Surface Cut Ply specimen is a convenient test coupon for the assessment of mixed-mode fracture in composite materials. It has been designed, manufactured, tested and verified by FE Analysis for measuring the mixed-mode Gc, the critical mixed-mode Energy Release Rate (ERR), for laminated composites. The desired mode mixity can be achieved through selection of the continuous to cut ply ratio; current work has concentrated on the 5/5 configuration which is a 10 plies thick specimen consisting of 5 cut and 5 continuous plies. The specimen is loaded in the 4 Point Bending configuration and a new analytical solution has been developed to compute the mixed-mode ERR from the specimen geometry and the recorded load - deflection test data. The simplicity of the test and that the need to measure the crack length is avoided are key advantages over other mixed-mode tests.