Volume 35, Issue 3 (May 2007)
Fatigue Prediction of Lightweight Thermoplastic Fiber-Metal Laminates
Lightweight thermoplastic-based fiber-metal laminates were developed based on a self-reinforced polypropylene and a glass fiber-reinforced polypropylene composite material with two sheets of aluminum alloy 2024-T3. The laminates were manufactured using a fast one step cold press manufacturing procedure. The mechanical behavior of the laminates was then investigated under tensile and fatigue loading conditions. The tensile properties of the plain aluminum, the composite materials, and the thermoplastic fiber-metal laminates (TFML) were investigated at quasi-static rates of loading. The fatigue tests were also conducted under load control based on the ASTM E 466 standard procedure. Various loading cycles were employed for the fatigue tests in order to minimize the possibility of heat generation on the composite materials. Three different load levels were applied for the fatigue specimens with zero to max loading. Results have shown that the glass fiber-reinforced polypropylene hybrid systems exhibited higher fatigue strength than the self-reinforced polypropylene based fiber-metal laminates. Following this, a simple prediction method for fatigue life of the TFMLs has been introduced. It is clearly indicated that the stress ranges calculated using the proposed method for the monolithic AL2024-T3 and the TFMLs are very similar at the same cycles to failure.