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Polyurethane foam continues today as the premier cushioning material utilized in automotive seating applications. In seating design, most foam properties specified by the design engineer in establishing foam properties currently are based upon static test methods. The in-service mode of an automotive seat, however, is dynamic rather than static. Therefore, the overlooked real time dynamic properties are of greater importance for the comfort performance of a seat than such static properties as Indentation Force Deflection (IFD) or density. Unfortunately, there are no widely accepted test methods for dynamically characterizing automotive seating foam. Correlation of real time dynamic properties to comfort could minimize the need for expensive, time consuming and subjective road testing. The purpose of this paper is to propose some potential dynamic characterization techniques for automotive seating foam.

Accurate and relevant assessments of foam performance in automotive seating applications have been achieved with a newly developed computerized laboratory test. In the new test a hydraulically powered indentor foot provides seat cushion foam loading in a dynamic mode, comparable to actual conditions of cushioning applications. In a relatively short period of time (∼ 8 hrs) it is possible to record several Real Time foam property changes related to seating performance. These properties are believed to be critical to in-use seating comfort and durability qualities. Moreover, the data obtained with the new test should be sufficiently reliable in assessing seating performance to reduce the need for extensive and rather costly in-car test track evaluations. The test device is equipped with a temperature and humidity chamber and is capable of evaluating fully fabricated seat cushion assemblies, as well as separate foam cushioning materials.