Finite element validation and non-proportionality quantification of lifting arm for agricultural mower based on experimental results

Fatigue is often driving the design of agricultural mowers as they are exposed to highly dynamic loading. The fatigue life of welded joints is well known to be reduced when exposed to non-proportional stresses. Thus, it is of great interest to quantify the levels of non-proportionality in agricultural mowers. In this paper, an experimental setup of a lifting arm in a mower structure has been developed in order to obtain experimental strain measurements. Based on the experimental setup, a digital twin is developed using the finite element method and the model is validated and updated against the experimental data. Using the digital twin in combination with a non-proportionality quantification approach, the levels of non-proportionality at four different locations of the lifting arm are predicted. The results show that geometry and loading influence the level of non-proportionality to a high degree.