Development & improvement of lightweight structures is a challenge in particular for land & marine vehicle production. SANDWICH will enhance the features and capabilities of steel sandwiches by filling them with different low-density cores. The aim is to develop panels for specific requirements defined by auto-, rail-, marine-industry. Sandwich improvements compared to conventional structures: 50% lighter, 50% space saving, 20% noise reduction and enhanced vibration properties, fire safety, crash worthiness, corrosion resistance. Erection time reduced 30%. 13 partners from 9 European countries, joined forces each an expert for one particular aspect and task. After a requirements analysis, design and production of the specimens and prototypes follows. A test phase delivers material behavioural data collected in a design tool which supports designers to develop tailor made sandwich products. A design guide assures type approval and thus marketing success.