Improvement of the Rigid Narrow-Point Heavy Cultivator Shank Design and Analysis of Stress Distribution Using the Finite Element Method

Heavy cultivators, which are widely used under dry farming conditions, are among the secondary tillage implements preferred for their ability to preserve soil moisture. Cultivator shanks that function by means of profound soil ripping generate considerable draft forces depending on the tractor's forward speed, and substantial deformations occur in the main frame connections due to the normal and shear stresses induced by these loads. It has been observed that the fastening components of fixed-shank heavy cultivators, which are widely used in the Eastern Anatolia Region, often fail to develop sufficient resistance against shear forces. This results in frequent damage and increased repair costs associated with the connection elements. In this study, a finite element analysis was conducted on a cultivator shank whose design had been improved and material selection re-evaluated, taking into account the operational field conditions under which the implement is used. Consequently, displacement and equivalent stress analyses were conducted under static loading conditions for the shank point and its fastening components. Thereafter, the safety factor of the parts against the applied loads was determined. The attachment of the shank point to the main frame is achieved by means of detachable fastening elements, namely bolts. The operating speed of the tillage implement and the soil structure were considered in the theoretical calculation of the force acting on a single shank, and an optimum mesh structure was generated accordingly. The rigid shank point and fixed shank were defined as normalized carbon steel (C30E); the support components as structural steel (S235JR); and the bolts as tempered steel of grade 8.8 (C45E). As demonstrated by the design improvements and analysis results, the total displacement was found to be 0.31 mm, while the equivalent stress on the connection bolts was determined as 71.81 MPa, and the safety factor was calculated as 8.91. It was concluded that, given the applied boundary conditions, the implemented design improvements and material selection, the calculated maximum equivalent stresses for the fasteners are significantly lower than the yield strength of the materials. This indicates that the cultivator leg components can operate safely.