A series of creep and relaxation experiments on scalp, brain, and dura from both human and monkey is described. An analysis of a practical creep loading with a rise time is given. An empirical expression for the observed creep curves is developed and deviations from classical viscoelasticity theory noted. A four parameter Maxwell-Kelvin fluid model is proposed and fitted to the creep data.
In addition, a free vibration test using the same equipment as the creep and relaxation experiments is presented. Analysis of this experiment yields values of the complex modulus in the frequency range 10–40 Hz.