Studies* show that roughly half of drivers take defensive action (such as sudden braking or steering) to avoid collisions, with vehicle occupants commonly bracing themselves at the same time. Occupant posture—whether braced or relaxed—has a significant effect on body movement during a collision. However, current human surrogate models used in virtual crash simulations are unable to simulate the reflexive defensive actions that humans take in the moments before an imminent collision, such as bracing one’s body for impact.
To address this, Toyota has successfully added a new muscle model capable of simulating human postural states in the latest version of its Total Human Model for Safety (THUMS) virtual human model software. THUMS Version 5 can simulate a variety of states from relaxed to braced, thus enabling more detailed computer analysis of injuries caused by collisions.
Until now, THUMS was only able to simulate changes in posture post-collision; however with THUMS Version 5’s new muscle model, changes in occupant posture prior to collisions can now be simulated.
This makes it possible to more accurately study the effectiveness not only of seatbelts, airbags and other safety equipment, but also of active safety technologies such as pre-collision systems. In turn, this will lead to development of active safety technologies that better protect vehicle occupants.
THUMS Version 5 is available through Tokyo-based JSOL Corporation and ESI Japan. THUMS has already been adopted by dozens of companies, including automobile and parts manufacturers, and is contributing to vehicle safety research all over the world.