Further research and co-operation of Fokker with Delft University, the Dutch aerospace laboratory NLR, 3M, Alcoa, and various other companies and institutions led to the first FML: the Aramid Reinforced ALuminum Laminates (ARALL), which combined aluminum with aramid fibers and was patented in 1981. This material had some cost, manufacturing, and application problems; while it had very high tensile strength, the material proved suboptimal in compressive strength, off-axis loading, and cyclic loading. These issues led to an improved version with glass fiber instead of aramid fibers.