Hyundai Motor Company virtually tests for seat vibrations early in the development process thanks to ESI’s Virtual Seat Solution

Reducing seat vibrations greatly contributes to improving a seat’s overall dynamic comfort, by protecting the occupant from muscular fatigue; an important issue for long journeys and with possible long-term effects on the spine. Han Ji Won, Engineer, Body & Trim development team at Hyundai Motor Company, declares, “Since seats contain lots of components, it’s very difficult to find the factors that influence the dynamic comfort of the seat. We tried to figure this out using ESI’s Virtual Seat Solution and reached our goal. This new way of working will help us save money and time effectively.”

ESI’s end-to-end Virtual Seat Solution, dedicated to the virtual manufacturing, testing and optimization of seats, has been used by Hyundai for many years to conduct virtual tests in several seat performance domains; including seating posture and body pressure and foam hardness. Recently, Hyundai’s Body & Trim development team sought to extend their usage of Virtual Seat Solution to evaluate dynamic comfort.

Traditionally, carmakers assess seat vibrations by asking volunteers to provide feedback on vibrations they experience; a method that delivers highly subjective results and has poor repeatability for many reasons, including the change of volunteer morphology with time. In an effort to overcome these drawbacks, Hyundai engineers started by developing and calibrating a new dynamic dummy model dedicated to vibratory tests.

With ESI’s Virtual Seat Solution, Hyundai engineers now use their dynamic dummy model to perform complete virtual dynamic tests of an occupied seat. The first step is to simulate the dummy sitting in the seat. This step is mandatory as it allows determination of the non-uniform compression of the foam in cushions of the occupied seat. 

The second step is to simulate the vibrations test with the seated dummy to obtain the transfer function that describes the capacity of the seat to absorb the vibrations. To achieve good correlation with real testing it is essential that the seat model – in particular the foam - inherits the correct properties from both the seat fabrication and dummy seating by “chaining” simulations of each step in the complete process.

Thanks to this fully validated dummy model, Hyundai performs virtual dynamic comfort testing with ESI’s Virtual Seat Solution earlier in the development process and can better arrive at the right seat design. The virtual vibration test is accurate and partly replaces real prototypes, thus allowing the car manufacturer to develop more comfortable seat designs in less time and at less cost. Virtual Seat Solution also saves time and increases efficiency by using a single core model of the seat to support evaluation of several seat performance domains and to enable design team collaboration.