Phase I - Initial Conditions

Several factors can influence the initial conditions used in the analysis. You'll see later that CASAS allows the use of scale factors to vary many of the input parameters making it easier to perform sensitivity analyses. Initial conditions are influenced by:

Case And Chamber As-Manufactured Dimensions - Tolerances can result in significant variation in the radial gap between case and chamber.
Case and Chamber Initial Temperature - A hot chamber results in larger initial radial gap and higher strains in the case during the firing cycle. Material properties can also be effected by elevated initial temperatures.
Case "Head Space" - Minimizing headspace is critical to controlling axial strain in the case.

Any design must allow sufficient initial radial (and axial) gap to accommodate the expected manufacturing tolerances and temperature extremes of the operating environment. One effect of having a cold round in a hot chamber is to increase the initial gap. Any increase in initial gap will increase total plastic deformation of the case.