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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.

A novel application in the field of Life Cycle Assessment is presented that investigates optimal vehicle retirement timing and design life. This study integrates Life Cycle Energy Analysis (LCEA) with Dynamic Replacement Modeling and quantifies the energy tradeoffs between operating an older vehicle versus replacing it with a new more energy efficient model. The decision to keep or replace a vehicle to minimizes life cycle energy consumption is influenced by several factors including vehicle production energy, current vehicle's fuel economy and its deterioration with age, the improvement in fuel economy technology of new model vehicles and annual vehicle miles traveled (VMT). Model simulations explore vehicle replacement under incremental improvements in vehicle technology and leapfrog technology improvements such as with the PNGV (Partnership for a New Generation of Vehicles).

While the results are generally the most exciting aspects of an LCI study, the details of the LCI model that generates the results are equally significant; particularly when modeling the life cycle of an automobile. The modeling challenges faced in conducting the US AMP LCI of a mid-sized vehicle based on the 1995 Lumina, Intrepid and Taurus are highlighted. The number of parts (over 20,000), supply chain complexity, materials composition, and the demanding set of OEM requirements for model features required special LCI methods and solutions. The LCI model and selected results are compared with previous studies, and recommendations for improvements in the USAMP LCI model are also provided. This paper is one of six SAE publications discussing the results and execution of the USCAR AMP Generic Vehicle LCI. The papers in this series are (Overview of results 982160, 982161, 982162, 982168, 982169, 982170).