Fuel Tank Strap Fatigue Sensitivity Study under Fuel Level Variation and Payload Variation

Fuel Tank Straps very often get different durability fatigue test results from different types of durability testing such as shaker table vibration, road test simulator (RTS) vehicle testing and proving ground vehicle durability testing. One test produces good durability results and other may indicate some durability risk. A special study was conducted to address this inconsistency. It was found that fuel level in the tank plays a big role in fuel tank strap durability. Higher fuel levels in a tank produce higher loads in straps and lower fatigue life. This paper will use a CAE fuel tank strap model and acquired proving ground strap load data to study fuel level influence in fuel tank strap durability. The fuel level study includes a full tank of fuel, 3 quarters tank of fuel, a half tank of fuel and one quarter tank of fuel. Based on CAE results of one 32 gallon fuel tank it is observed that fuel tank strap fatigue life improves by one order of magnitude or 10 times for every quarter tank of fuel level reduction. In addition to fuel level, payload influence is also studied. It is observed that vehicle payload has some positive influence. A full payload test condition can improve fuel tank strap fatigue life by 3 times compared with zero payload condition.