Determining of Cutting Force of Annual Medics Seed

Annual medics seed have woody spiral pods that need to be threshed before planting. This can be done during harvesting. In order to design the harvester system, pod cutting force has to be determined. The required force for cutting the pods of two species of annual medics (M. scutellata, M. rigidula) was determined by conducting an experimental design. Independent variables were pods moisture, cutting speed and cutting direction of pod. In order to support the samples in tension-compression testing machine head, a special clamp was designed and developed. Results of statistical analysis of the data indicated that in most of the conditions, cutting force for M. scutellata increases with increasing moisture content. Cutting force had a significant relation with the direction of application and was lower when applied perpendicular to the pod axis as compared with the parallel condition. Increasing the cutting speed from 0.16 mm/s to higher speeds (10 or 100 mm/s) decreased the cutting force for the M. scutellata species. Cutting energy determined based on the area under the force- deformation curve, was used in calculation of power requirement for the threshing system of the annual medics seed combine harvester.