Most medical devices and materials exhibit frequency-dependent behavior. This sometimes presents a challenge when testing at high frequencies (40-60Hz). Device mass or material loss modulus may attenuate or dampen the device response as the test frequency is increased. This could alter the strain amplitude that you are hoping to achieve with the accelerated test. For any test setup involving significant strain it is best to validate that the desired motion is being met at the accelerated test frequency. Motion validation studies are performed in several steps:
Figure I shows an example of radii analysis for a pacemaker lead. The analysis ensures that the minimum and maximum radii are achieved at the accelerated test frequency. When designing a high frequency test, frequency dependent behaviors need to be taken into consideration and validation techniques need to be used to ensure that the test is accurate. MDT performs high speed video validation of accelerated high strain tests on a regular basis to ensure that our tests are the most accurate available.