Composite Testing
Abstract
Recent research both in the USA and Europe has focused on characterising the behaviour and ultimate load capacity of adhesively bonded joints for both composite-to-composite and composite-to-metal hybrid systems. The EUCLID (European co-operation for the long term in defence) project conducted a large number of both static and dynamic tests on both bonded composite and metal-to-composite connection details [1]. The connections were T-joints made using conventional composite materials using a vacuum-assisted resin transfer molding (VARTM) process. The dynamic load was simulated via a shock table to impart strain rates to the specimens typical of those expected in external air blast scenarios. For the all composite joints, core shear failure appeared to be the main damage to the joint, initiating the failure of the overall system for the range of loading studied. However tests carried out at the National Laboratory of Denmark, RISO, showed core shear failure to occur for quasi-static loading and debonding of the overlaminate to the base panel occurring for the higher loading rates with little core shear failure observed [2]. McGeorge et al. [3] reported on a study comparing the base design and an improved design for joint details in a potential hangar design using a balsa core and glass reinforced polymer (GRP) skins. The connections clearly governed the vulnerability of the superstructure. However the improved designs which allowed more flexibility of the joint detail indicated a doubling of the capacity. The capacity of the details was heavily controlled by fine details of the joints and the quality of their manufacture which is heavily workmanship dependent. A summary report issued by Det norske Veritas [4] gives a good overview of the project and the key findings. The figure below shows the response of the original and modified design. In the traditional joint the high stress concentrations and peeling occur at the edge of the steel insert.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2007
- Accession Number
- ADA520819
Entities
People
- Sarah Mouring