20. Connecting Rod FEA Validation Using Digital Image Correlation

Standard structural analyses were performed on a connecting rod in order to assess its durability. The finite element (FE) model predicted a significant amount of ovalization at the crankpin (i.e. big) end of the connecting rod when subjected to high tensile loads. This ovalization imposed a large bending moment on the crankpin end cap screws. Accounting for the cap screw’s axial preload and the bending moment, the combined stress state was very near the yield strength of the cap screw. It was desired to experimentally validate the FE model. Therefore, an axial tension test was conducted on a sample connecting rod and the deformation near the cap screws was measured using digital image correlation (DIC). Both the axial and lateral deformations between the analytical and experimental data were very well matched. The results of this investigation showed that with good modeling and experimental methods, DIC can be an effective method for model validation.