Offsets between tubes at nodes need a detailed analysis similar to 5.3 where the actual connection is modeled using the end constraints from the overall vehicle model. Shell or solid models must be used.
AF5.6 The following alternative boundary condition is acceptable for all structural requirements. The alternative is to not include the nodal constraints and instead run the model with inertia relief. In this case the mass distribution of the vehicle must closely approximate the actual intended mass distribution. Evidence must be provided supporting the mass distribution used in the model. A driver mass of 77 kg and a minimum vehicle mass of 300 kg must be used, even if these differ from the team's predicted vehicle mass.