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Canning is a very important aspect in the catalyst converter design, especially with the current trend of using more thin wall and ultra-thin wall substrates. This paper systematically investigated canning issues at different stages of converter manufacturing processes and operations. Commonly used converter canning processes, which include traditional clamshell style and tourniquet wrap, are included in the studies. Using a previously developed mat material model, visco-elastic behavior, as well as the unique expansion characteristic of the intumescent mat under high temperature, are included in the simulations. Lab testing of the mat material at different loading speeds was conducted to obtain the visco-elastic properties. These will allow the studies of the effect of closing speed on the peak pressures during canning processes, as well as the pressures during heating and cooling.

Intumescent mat is widely used to support ceramic substrates in catalytic converters and is subjected to thermo-mechanical loading. As the substrate wall thickness becomes thinner to reduce backpressure and emission, exact prediction of mat pressure becomes more important in design stage to prevent future substrate failure during the canning and thermo-cyclic loading test. Experiment shows that the mat mechanical behavior is very much like highly nonlinear rate dependent hyper-foam material and it has permanent plastic deformation after either thermal or mechanical loading. Also, mechanical material property changes due to the temperature. This paper introduces some of the key features in developing constitutive model based on the hyperelastic theory by including viscous and plastic effects. To account for material property change at each temperature, material softening model will be introduced with respect to temperature and mechanical strain.