XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX''"> Concluding Remarks
Once the strain histories have been generated from the FE model, they may readily be compared with the corresponding measured strains from the real component. The possible methods for comparing them shown in this exercise are:
• Multi-File Display (MMFD) to overlay or cross-plot the data
• Comparison of signal statistics (max, min, RMS, etc.)
• Strain gauge rosette analysis option (MSSA)
• Single location uniaxial fatigue analysis (MCLF)
• Single location multiaxial fatigue analysis (MMLF)
Correlation is a very important aspect of reliable durability calculations. If a correlation exercise indicates that there is poor qualitative and quantitative correlation between predicted and measured
strain histories, any fatigue calculations are also likely to give poor results. Likely causes of poor correlation are:
• Errors in setting up the MSC Fatigue job, particularly in matching the correct channels to the correct load cases with the correct scaling factors
• Errors in calculating the loading histories
• Poor definition of the loads and boundary conditions, or missing loads
• Inadequate meshing
• Inaccurate strain gauge placement
• Inappropriate analysis (e.g. quasi-static when the problem is dynamic)
• Poor materials
• Non-proportional loadings together with high levels of plasticity