Selecting material for the exterior panel of a private car back door by adopting a total cost accounting approach

A total cost accounting approach for material selection is demonstrated by analysing the suitability of some light weight materials for use in the exterior panel of a back door to a private car. For pre-selection purposes, the suitability of using low alloy steel, aluminium, SMC and a hybrid GMT/aluminium material as construction material for the exterior panel of the back door are compared by taking into account differences in production cost, cost associated with excess mass, cost of probable failures and damages, maintenance and operational costs, end-of-life cost, and cost associated with probable ecological damage. From one manufacturer’s point of view and considering only the production cost for the installed part of the back door, steel is the best alternative for large production volumes. However, this is not the case when taking into account all costs. All the other materials seem better and exhibit essentially the same qualities. The main reason is lower fuel consumption. The results of the suitability analysis nicely reflect the relative importance of the various factors contributing to the total cost but the suitability analysis also points to the need of performing a more advanced analysis taking into account also aspects like safety and ease of surface treatment.