Finite element (FE) brain models have been used as an effective tool for the investigation of traumatic brain injuries. The biofidelity of these models has been improved constantly in recent years. However, the inhomogeneous mechanical characteristic of brain tissue has to a large extent been neglected in FE brain modeling. The objective of this study was to determine the effect of such inhomogeneous characteristic on brain responses under traumatic mechanical loadings. Based on region‐specific experimental rat brain tissue responses, an inhomogeneous rat brain FE model was developed. Sagittal plane rotational impact tests were simulated and intracranial dynamic responses of the new inhomogeneous model were compared with those of a homogeneous model.

The stress responses changed distinctly from the homogeneous model to the inhomogeneous model while dramatic and significant differences of the peak values were observed in the hippocampus, brainstem and cerebellum. The strain responses of these two rat brain models were similar while the significant difference of the peak values was only observed in the hippocampus with a small relative error.

The study illustrated that the intracranial stress responses were more sensitive to such inhomogeneous characteristic than the intracranial strain responses when the head is subjected to rapid sagittal plane rotational acceleration trauma.