def METHOD_NAME(self, property_id=None):
    # A * (rho * t + nsm)
    if property_id is None:
        property_id = self.property_id
        n = len(property_id)
        i = arange(n)
    else:
        self.model.log.debug('property_id = %r' % property_id)
        n = len(property_id)
        i = searchsorted(self.property_id, property_id)
    mpa = zeros(n, dtype='float64')
    rho = self.model.materials.get_density_by_material_id(self.material_id)
    mpa = rho * self.thickness[i] + self.nsm[i]
    return mpa