Malcolm Nash FRAeS, Chairman of the Structures & Materials Group, has kindly written up a review of the 'Future Trends in Certification of Advanced Technology Structures' conference held at the National Composites Centre near Bristol on September 16th 2015.
The aim was to examine how designers and manufacturers are modifying their processes in order to produce new products in a shorter timescale and at lower cost, whilst continuing innovation and ensuring safety. Unusually, the products considered went beyond fixed-wing aircraft and included both space vehicles and Formula 1 cars.
Although the conference was not specifically limited to composite structures, the majority of presenters worked in the composites area. The first presentation described the activities of the National Composites Centre itself, including its setup, involving a group of different organisations working in the composites field, each of whom pays a membership fee and works in the NCC to support its own product developments. Different groups working in the same environment naturally supports an element of cross fertilisation of ideas. This presentation was complemented by one from the NCCEF (National Composites Certification and Evaluation Facility) at Manchester, which concentrates on testing composite structures. The speaker suggested a change in the manufacture of carbon fibres from the current norm of 7µm diameter to 12µm. The following questions from the audience discussed the pros and cons of this proposed change.
A presentation from QinetiQ described the activities in the first and second worldwide composites failure exercises. The paper looked at how the formulae used to calculate composite failure, included in many commercial structural analysis codes, performed in a series of test problems comprising composite specimens loaded in different ways. A number of failure criteria were found wanting and some have subsequently been revised. A third exercise was described which would build confidence in the ability to model structures and subsequently reduce the amount of testing required.
Three further presentations looked at specific platforms. One from ESA described the complex, large scale testing facilities required to ensure the integrity of structures subjected to high levels of noise and vibration on launch as well as thermal loading in all phases of use. An Airbus presentation described how experience built up over many years of airframe development enabled them to tackle new structures with confidence and how they could model full scale test structures in the test process and produce modifications to prohibit damage to the test article based on the test results. A presentation from Mercedes F1 described the many tools and processes used to allow them to go from a CAD representation to a completed composite component in six days in some cases. Unlike some other products, the F1 car is dominated by a stiffness requirement.
The conference concluded with a visit to the NCC facilities. Overall, the event was successful in revealing how various organisation are going about the aim of improving and speeding up their certification procedures. It was also successful in producing some cross-fertilisation of ideas.
Dates for your Diary
Details of upcoming Structures & Materials Group events can be found below:
14 March 2016 / London
The Group are still finalising the details of this event so please check our website here for updates.
5th Aircraft Structural Design Conference
4 - 6 October 2016 / Lisbon, Portugal
This conference will address the challenges facing the designers of the next generation of aircraft. A call for papers is currently open for this conference and seeks contributions covering current research focused on the design and manufacture of future civil and military air-vehicle structures, both manned and uninhabited. The deadline for submitting abstracts is 11 March 2016.
Click here to find out more.