On the Use of Polyurethane Foam Paddings to Improve Passive Safety in Crashworthiness Applications

The use of cellular materials in general in the automotive industry, and polymeric foams in particular, has been increasing significantly for the last few decades. These materials are used within a particular vehicle for many different purposes, among which are, for example, sound and thermal insulation, vibration damping, fire protection and, of course, crashworthiness. Thus, crashworthiness, safety and protection parameters are strongly influenced by the materials used and, as a consequence, polymeric foams play a major role in the vehicle’s crashworthiness levels. In absolute terms, the energy absorption capability of this class of materials can lead to significant improvements on the vehicle’s passive safety, better protecting the passengers from aggressive impacts, by absorbing impact energy in a gradual and controlled manner. In addition, design limitations due to environmental constraints are growing steeply as are safety concerns. Whilst the former often leads to a reduction in the weight of the vehicle, the latter will most probably lead to the opposite. Therefore, the combination of properties such as low density, low cost and design flexibility with a great energy absorption capability, is what makes cellular materials so attractive for the automotive industry.