Reducing the weight of the M1A2 tank by lightweighting hull, suspension, and track results in 5.1%, 1.3%, and 0.6% tank mass reductions, respectively. The impact of retrofitting with lightweight components is evaluated through primary energy demand (PED), cost, and fuel consumption (FC). Life cycle stages included are preproduction (design, prototype, and testing), material production, part fabrication, and operation. Metrics for lightweight components are expressed as ratios comparing lightweighted and unmodified tanks. Army-defined drive cycles were employed and an FC vs. mass elasticity of 0.55 was used. Depending on the distance traveled, cost to retrofit and operate a tank with a lightweighted hull is 3.5 to 19 times the cost for just operating an unmodified tank over the same distance. PED values for the lightweight hull are 1.1 to 2 times the unmodified tank. Cost and PED ratios decrease with increasing distance. Fuel savings from lightweighting do not offset lightweight part production and retrofitting costs for realistic distances. A life cycle refurbishment/refitting analysis of these components was conducted to evaluate part production and operational impact differences between lightweight and heavier components. The cost ratio between lightweight and heavier hull varies (with distance) from 1.58 to 1.96 and the PED ratio ranges from 1.0 to 1.07. These ratios are more favorable than those above, primarily due to the inclusion of upstream life cycle stages for unmodified tanks. Lightweighting decisions usually consider cost and energy tradeoffs, but other logistical and mission-oriented objectives are also critical in deciding to lightweight vehicles, especially military ones.
CSS Publication Number:
SAE Technical Paper
April 14, 2020
Sullivan, John L., Geoffrey M. Lewis, Gregory A. Keoleian, Rob Hart. (2020) “Energy, fuels, and cost analyses for the M1A2 tank: A weight reduction case study.” SAE Technical Paper 2020-01-0173: 1-8.