ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

(excluding the cadaveric validation) were simulated in the form of individual case
studies.
Fig. 3: Midsagittal cross-section of biofidelic head model.
7. RESULTS AND DISCUSSION
The normalized results of the fluid-filled sphere head (Stage 1) sensitivity study are
presented below in terms of non-dimensional pressure (i.e. pressure “magnification”)
against the ratio Tp / TΩ.
Pressure magnification P peak/P quasi
9
6
3
0
-3
-6
-9
0.1 1.0 10.0
Ratio Tp/T Ω
peak +'ve pressure
peak -'ve pressure
Coup Contrecoup
-9
0.1 1.0 10.0
Fig. 4 and 5: Fluid-filled sphere: normalized pressures vs. time at the coup and
at the contrecoup respectively.
As was expected, for comparatively long duration impacts (Tp / TΩ > 2) quasi-static
pressure behavior is observed in the brain. Peak positive pressures occur at the coup,
and peak negative pressures occur at the contrecoup, while negative pressures at the
coup and positive pressures at the contrecoup remain low. These peak pressures remain
relatively constant due to the consistent peak impact force. As contact duration is
reduced past a critical value of approximately Tp / TΩ = 2 the nature of the response
changes: the magnitude of the peak pressures observed increases, and large positive and
negative pressures are observed at both the coup and contrecoup. The maximum
observed pressure magnification from this Stage 1 study is a dynamic positive pressure
8.6 times greater than would be predicted from the quasi-static response, occurring at
Pressure magnification P peak/P quasi
9
6
3
0
-3
-6
Ratio Tp/T Ω
peak +'ve pressure
peak -'ve pressure