Innovative stainless steel panel applications for transport industries

All-metal sandwich panels of three different basic configurations were manufactured of austenitic stainless steels by laser welding. The panels were subjected to exhaustive mechanical testing programme including constant load and four-point bending tests for full size 2.5 m2 panels, and fatigue and crash testing of smaller panel sections. Reference panels were manufactured by adhesive bonding and by using insulating foam in a basic welded panel. All the panel types fulfilled the set requirements for the static, i.e. design loading, and fatigue situations - no requirements were preset for crash properties. Once the panel surface sheet thickness and total panel thickness are fixed, there are no significant differences between panel types, material strength or manufacturing routes from the load bearing point of view. The reason is that the practical structural properties are stiffness dependent. The differences in panel type, material strength or assembly method only become evident at loads and displacements way beyond acceptable in transport equipment service - apart from exceptional impact load situations, such as crash or collision. The choice between panel types has to be based on other issues, such as weight optimisation, ease and cost of manufacture, or aesthetics.