EndoLab - Implant Testing Services Implant Testing

News  25.02.2019

Impact resistance test according to ISO 11491 on ceramic femoral heads

The impact resistance and cyclic load-release burst test according to ISO 11491 complements testing of ceramic femoral heads.

The standard ISO 11491 describes a test method for impact resistance as well as a the test method for the cyclic load-release burst test of ceramic femoral heads.
For impact resistance, the EndoLab® semiautomatic drop tower is used. An impact energy is applied by a free-falling dead weight. The impact energy is progressively increased in steps of 10 J until the femoral head fractures. A high speed piezoelectric sensor is used to determine the impact load.
The cyclic load-release burst test is performed on a 300 kN EndoLab® servohydraulic testing machine. An initial force of 20 kN is applied to the test specimens and kept constant for defined period. Subsequently the initial load is released to 0.2 kN and the load is maintained for 5 minutes. After this waiting period, the load is increased again to the previous maximum force plus 5 kN and released again to the unloaded state. This procedure is continued until failure of the ceramic femoral head or the neck occurs.
In case of doubt, Endolab® prefers the load-release burst test due to its better reproducibility between test labs.