High strain rate compressive behaviour of human heart

Thoracic injuries incurred during crashes constitute a significant portion of all fatal and non-fatal injuries. Finite element human body models are used to understand the injury mechanisms to critical organs like the heart for improving crash safety. Major insight can be gained into its injury mechanisms by studying its compressive behaviour at strain rates seen in impact (up to 300/s). This study reports a total of 20 compression tests performed on heart tissues at strain rates ranging from 0.001/s to 200/s. Green strain was calculated from displacements which were obtained from analysis of high speed video recordings. Stresses were calculated from the measured force and initial cross-sectional area. The study showed that the response of heart tissue was non-linear and strain rate dependent. The elastic modulus also varied with strain with values ranging from 1.79e-3 MPa to 3.34 MPa at compressive strain of 15% to 46%.