A combined approach of numerical modeling and animal experiments was used to study the mechanisms of traumatic brain injury (TBI). A three‐dimensional finite element model (FEM) of the rat brain was submitted to experimental sagittal plane rotational acceleration pulses. The experimental setup provided histological analysis of injured brain tissues for a range of severities. The biomechanical response parameters were extracted from the FEM in the anatomical regions identified by experiments as prone to injuries. Von Mises stresses and first principal strains proved to increase with both the amplitude of acceleration loadings and the tissue injuries severities. Further comparison between mechanical responses and experimental histological scores allowed proposing tissue thresholds for the occurrence of TBI, namely 1.5 kPa and 4% approximately for Von Mises stresses and first principal strains, respectively. Those values can be used for further investigations of the mechanisms of TBI.