Page 97 - Clinical relevance of current materials for cranial implants

Finite Element Analysis
The maximum tensile stresses in the models under a load of 100 N in respectively the center and the weak spot in addition to the resulting translations are shown in Table 3 and Figure 7. The stress under the load of 100 N on the weak spot was 12.2 MPa. Since the material displays linear elastic behavior, a load of 503 N is needed to fracture the implant. This load corresponds with hitting a flat and hard surface at a speed of 0.42 m/s which results in a similar fracture stress.
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In vivo fractured PMMA cranioplasty
Figure 7: Tensile stresses, in MPa, resulting from a load of 100 N perpendicular to the top surface of the implant model. The implant model is depicted from a bottom view.
Table 4: Maximum tensile stress (σmax), in MPa, and the total translation (l), in mm, resulting from a load of 100 N perpendicular to the top surface of the implant model at the specified location.
Location
Center
Weak spot
σmax l
3.8 0.091
12.2 0.159
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