ESI Updates Its PAM-CEM Simulation Suite

ESI has released the 2009 version of its PAM-CEM software package for computational electromagnetics. The PAM-CEM Simulation Suite offers industrial coupling capabilities to address realistic models in their early design stage and to assess real electromagnetic multi-scale phenomena occurring in the middle and high-frequency ranges.

PAM-CEM can handle 3D models featuring on-board complex antennas and realistic cable networks. PAM-CEM Version 2009 includes several key enhancements that benefit transport, aeronautics and defence, as well as the telecommunications and electronics industries. For example, it provides direct access to the electromagnetic fields radiated in the 'near zone' surrounding the 3D computational domain.

It can account for distant antennas or high frequency onboard automotive radar devices, without major computational drawbacks. The EMS (Immunity) interpolation scheme has been improved to allow cable networks to run close to the metallic (meshed) structures, thus avoiding hand-made running path redesign.

The PAM-CEM/FD output process has been reviewed, with ESI adding dedicated calibrating and/or normalising options (fully automatic or user controlled) and dedicated output of induced currents along cable networks for 3D display with Visual-Viewer. PAM-CEM Version 2009 features Visual-CEM 5.5, a dedicated user environment allowing the management of billions of unknowns, leading to higher operating frequencies. This has improved the overall performance, including graphical user interface and ease-of-use.

Pam-Comfort Helps Renault Design New Seat

Renault has used ESI's Pam-Comfort system for the preliminary design of a new seat. ESI's Pam-Comfort software offers a scalable and customised solution dedicated to virtual manufacturing and virtual testing (static and dynamic) of the soft parts of a seat. Virtual seat prototyping consists of several chained simulated steps ranging from seat manufacturing and occupant static seating, to occupied seat NVH (noise and vibration), where the stresses resulting from each step are needed for the next one.

The chaining is necessary to accurately predict the behaviour of the seats under numerous loading conditions (trimming, dummy loading, various human anthropometries and vibrations) and for various design changes (materials and shape). At Renault, where the full virtual seat prototyping methodology is being deployed, an important step after the preliminary design of a new seat is the virtual testing of the dynamic comfort performance using Pam-Comfort.

To accurately predict seat comfort, Renault runs a dynamic test of seat transmissibility with a static weight. The test helps evaluate the seat frequency response and thus informs Renault about how the seat contributes to the vertical acceleration filtering of the car, which is important for dynamic seat comfort. This test is used to improve and validate the seat design. Renault simulated this test procedure with a finite element calculation using Pam-Comfort. After completing the seat-manufacturing simulations, a dummy is imported in the model to launch the computation.

This calculation is divided in two phases: first, a static phase in which the dummy is seated and where the equilibrium is computed to precisely know the stress and strain states of the various parts of the seat; second is a dynamic phase in which a vertical acceleration signal is applied to the seat rail to obtain the seat dynamic transmissibility at the interface with the dummy. Computed results showed a good level of correlation with physical tests, therefore confirming the validity and predictability of both Renault's simulation modelling and the methodology applied.