# Structural Strength Analysis of a Rotary Drum Mower in Transportation Position
## 2 Materials and Methods
### Finite Element Analysis  
A reverse engineering approach was utilised to manage the solid modelling operations for the RDM, as the manufacturer did not have a detailed computer-aided design (CAD) model to be utilised for an FEA. Using this approach, each component of the machine was disassembled, the standard machine components utilised in the machine were identified, and the geometric parameters defining the other components were measured with the aid of tools such as callipers, tape measures, and micrometres, etc. Next, 3D parametric solid models were created using SolidWorks 2011 (SW) 3D parametric solid modelling software. With reference to the original machine assembly, all of the machine's components were assembled throughout the parametric modelling phase in order to finalise the solid modelling of the entire machine. Steel-based materials are used to manufacture almost all of the machine's components. Rubber-based materials are utilised as bedding and sealing in motion transmission components. The solid model of the RDM has the mobility that it actually has in real life. The mass criterion is one of the factors considered in determining whether generated CAD models can accurately represent physical structures. The material property characteristics that were set in the solid modelling software were used to compute the tool's overall mass. The software determined the overall mass for the RDM CAD assembly to be 424.15 kg (experimental mass measurement value: 423.93 kg). The parametric CAD model of the RDM was re-configured for the FEA study. The CAD assembly contains a significant number of components; thus, a simplification procedure was performed without affecting the model's capacity to structurally represent the machine. Some of the standard machine elements and functional element groups' (drum group and gearbox) geometries have been simplified during this re-configuration of the RDM CAD model. The structural components' initial geometries were preserved. In the re-configurated CAD model, the drum set and gearbox were re-organised as a solid block with rectangular prism geometry while preserving their original weights. The holes on some of the elements were patched properly. The surfaces which they come into contact with were considered, and the angular geometries of machine components like bolts, nuts, etc., were rounded. The machine's total weight and the location of its centre of gravity were preserved despite all of the simplifications. In this procedure, the ideal solubility level for the FEA was provided by means of a re-configured CAD model. The solid modelling procedure, final assembly, re-configuration process, and assembly statistics for the RDM CAD model are given in Figure 7.  
Figure 7: Solid modelling procedure, final assembly, re-configuration for the FEA, and assembly statistics for the RDM. Standard machine elements including springs, bolts, nuts, pins, shafts, etc., as well as structural components are used in the production of the RDM. In the FEA investigations, the material properties of these components are obtained from the literature given by the applicable standards and previous material testing results of the machine's structural components. Table 1 provides the material properties for the components utilised in the CAD modelling and the FEA study [20; 21; 22; 23; 24; 25; 26]. The real-life boundary conditions were considered in the FEA study with reference to the position where the machine was linked to the tractor and lifted to the static linkage position with a \(7.10^{\circ}\) angle (in-garage static linkage position). The main load acting on the machine in the static linkage position is the total weight of the machine under the effect of Earth's gravity. The gravity acceleration was defined as 9.81 m s\({}^{-2}\). The FEA study was carried out for the transportation position at static linkage in order to provide validation by comparing numerical and experimental analyses results. The FEA study was divided into two stages.