Master Thesis - OUFTI-1

• Global mass/stiness smearing method: Both mass and stiness of each component
are spread out over the entire area of the PCB. To apply this method to a
particular model, the same calculation than in the previous point, must be performed
to obtain the global density. The global stiness is achieved using an area weighted
average of the locally smeared Young's moduli as shown in Equation 4.2.5.
E global =
∑
Ei A i
A total
(4.2.5)
where E i is the Young's modulus at the location i on the PCB, A i is the surface area
of this location and A total is the total surface area of the PCB.
• Local smearing method: This method is the same as the previous one, except
that, instead of smearing the components properties over the entire PCB, they are
spread out over local regions of the PCB, where the local regions can be dened as
the projection of the components area on the PCB.
These methods are illustrated in Figure 4.8.
Figure 4.8: Illustration of the dierent simplication methods [45]
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