Design and production of cruciform composite specimens for in-plane biaxial tests

This paper focuses on the design of a cruciform specimen for biaxial in-plane tensile testing. Using a Finite Element model and experimental data, a proper specimen geometry was developed. The specimen has an adapted fillet corner radius to increase the load transfer to the specimen centre and has a reduced thickness in the centre to ensure biaxial failure in this zone. The production of this specimen is until now accomplished by milling material away from the centre, which can cause damage of the specimen material. Other production techniques are analysed. Also, the effect of the lay-up in the reinforced arms on the strain distribution in the central gage section of the specimen is examined.