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.
Correlations with testing data using Tekscan, a real time pressure measuring system, were conducted, and good correlations between simulations and testing are observed. Shear stresses on the substrate are then calculated using the pressures obtained earlier. Two substrate failure modes, cell collapse under canning pressure and shear failure under maximum shear stress, are investigated. Manufacturing tolerance effects are also investigated. These comprehensive canning simulations will significantly improve predictions of structural integrity and durability of the converter design, and optimize the canning processes prior to initiation of high cost/long lead time items.