Finite element lnodel1ing is used to investigate the complex stress states in roller shells
and shafts. Predictions, coupled with factory observations indicate key prohlem areas
that must be addressed to reduce the occurrence of fatigue related damage to mill
rollers. This paper discusses the design approach adopted for this investigation. Firstly,
a detailed analysis of the complex stress state in an exisling mill roller was undertaken,
Interference fits, nominal roll and torsional loads were applied and resulting stresses
were investigated. The effect of roller lift and associated misalignment loads on roller
stress was also examined. Analysis of several alternative roller designs followed.
Variations in geometry, shell material and attachment methods were investigated, "The
resulting stress states in the critical fillet and shell-end regions highlight specific
problems with existing designs. An alternative design is presented which should have
substantially improved durability, Finally, durability modelling of the existing roller
design was undertaken. A simple model based on fracture mechanics theory is used to
evaluate the structural integrity of a cracked mill roller. This model may be used bv
factory engineers to assess the likelihood of catastrophic failure of a cracked roller shaft
under known loading conditions. A case study predicting the critical crack depth and
crack propagation rate for candidate mill roller shafl is presented.