The FSI simulation (Fluid-Sstructure-Interaction) describes the interactions between mechanics and flow on the components under consideration. Thereby CFD analysis and FE- Analysis coupled with each other. In this simulation example, the influence of air cooling by heat conduction and heat transfer at the cylinder head on the mechanical stresses, deformations and forces in the component is to be investigated. To carry out the simulation FE- Calculation and CFD Calculation are coupled with each other in such a way that the partial results of the respective time step are available as boundary condition for the FEM calculation as well as for the CFD calculation. Thus, the usability of the results depends on the error-free data transfer at the interface between FEM model and CFD model.
FE- Calculation
For a stable FEM calculation, the model is constructed as cleanly and structured as possible. For the aluminium alloy (EN AW-7075 T6) the following material data are specified:
- Density
- Young's modulus
- Poisson number
- Thermal expansion coefficient
- Specific heat capacity
- Thermal conductivity
Heat capacities and thermal conductivities are considered to be temperature dependent for the aluminium alloy.
Boundary conditions for the FE analysis
The head gasket compensates for the different thermal expansions between the crankcase (grey cast iron) and the head (aluminium). It also compensates for unevenness in the sealing surfaces that occurs over time due to the loads acting on them. Since only the cylinder head is to be considered in the FSI simulation and the gasket is flexible, it is not shown in this case. For simplification, it is therefore assumed that the gasket surface is fixed.
- Bearing: Fixed bearing around the bolt heads and on the sealing surface
- Load: Temperature load on the entire base area
No forces or pressures are defined as initial conditions. Before coupling with the CFD calculation, the FEM calculation is performed and evaluated for result validation.