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

4.2 Case NG09
The numerical impact simulation predicts fracture patterns on the frontal bone as
illustrated in Figure 3. The linear fracture through the left orbita is not predicted since
the face has only a linear elastic behaviour in the model. Therefore, the fracture pattern
stops on the frontier between the skull and the face. Nevertheless, a global fracture
region is predicted by the model even if the location is not as accurate as the one
observed in the experience. In terms of interaction force between the head and the
impacting mass, the numerically calculated amplitude reaches the same level than the
experimentally measured one as illustrated in Figure 3. Moreover, the duration of that
first impact is the same in the experimental impact as in the numerical impact. Besides,
the numerical simulation shows a second impact which is also observable in the
experience with approximately the same amplitude and duration. Eventually, the
calculated global strain energy of the skull reaches levels of 12,000 mJ and thus allows
the model to predict skull fracture since the limit relies on 833 mJ.
Figure 3: Skull deleted elements numerical prediction (left), and experimental (blue)
and numerical (pink) interaction force between the head and the impactor (right).
4.3 Case NG15
The numerical impact simulation predicts fracture patterns on the frontal bone as
illustrated in Figure 4. It can be concluded that the multiple fracture patterns extending
to left temporal are basically predicted by the model. In terms of interaction force
between the head and the impacting mass, the numerically calculated amplitude is 3,000
N higher than the experimentally measured one as illustrated in Figure 4. Nevertheless,
the first impact duration is the same in the experimental impact as in the numerical
impact. Moreover, the numerical simulation shows a second impact which is also
observable in the experience but with a lower amplitude. Eventually, the calculated
global strain energy of the skull reaches levels of 22,000 mJ and thus allows the model
to predict skull fracture since the limit relies on 833 mJ.
Figure 4: Skull deleted elements numerical prediction (left), and experimental (blue)
and numerical (pink) interaction force between the head and the impactor (right).