Presentation of Finite Element Analysis

MATERIAL AND METHOD

 

Designing of the Sidelifter 

Assembly modelling is used for creating designs that consist of two or more components assembled together at their respective work positions. The components are brought together and assembled in Assembly Design workbench by applying suitable parametric assembly constraints to them. The assembly constraints allow restricting the degrees of freedom of components on their respective work positions The assembly files in CATIA V5 are called product files.  

Infrastructure Application Tools;  Real Time Rendering Workbench is used for the tools of light create, environments, turn tables and simulations for picture and video renderings of the CATIA V5 products

Digital Mock-up Application Tools; DMU Kinematics Workbench is provided the tools to help the user apply and extract kinematics information about a design. As shown in Figure 4.5, part intersections into assembly detected with the aid of this workbench. 

Solidworks software program was used for the developments of the mechanism with RAYVAG Railcar Industry and Trade S.A. Technical drawings of sidelifter mechanism were prepared with the aid of this program. Parts were prepared as sheet metal at Solidworks. By using bench, parts have been seen as fold and unfold through design steps. General view of solid modal and draft of a sheet in SolidWorks can be seen in respectively.  

Finite Element Analyses 

FEA software typically uses a CAD representation of the physical model. In this thesis, In order to calculate operation stresses on the prototype 2 different types of loading operation have been analysed by following the chart in Figure 4.9.  Analyses are carried out in Çukurova University Automotive Engineering Laboratories with the aid of workstation, which has 2 processors (24 cores) and 32 GB RAM. Although, in practical world, heaviest container has 30.400 kg weight, in this study, 40.000 kg weight is applied at analyses for unexpected service conditions, which are;  Distribution of 40 tonnes load on the chassis (to symbolize when the container is settle on the chassis after loading operation)   40 Tonnes loading from the hooks (to symbolize when the container is loading and unloading) The following assumptions have been done in analyses;  It is assumed that the material behaviour is linear elastic and strains are small. Therefore, linear elastic analysis will be carried out.  Pins and links are assumed rigid.  The loads are applied statically.  It is also assumed that material properties of the structure are homogenous and not changed after heat treatment (welding operation).

The Four Node Tetrahedral Element 

The four node tetrahedral element (shown in Figure 3.2) is the simplest three dimensional elements used in the analysis of solid mechanics problems. This element has four nodes with each node having three translational degrees of freedom in the nodal x-y-z directions (Moaveni, 2008). 

The Eight Node Brick Element (Hexahedron Element) 

The eight node brick element (shown in Figure 3.3) is a simple three dimensional element used in the analysis of solid mechanics problems. Each of the eight nodes of this element has three translational degrees of freedom in the nodal xy-z directions (Moaveni, 2008).  

The Ten Node Tetrahedral Element  

The ten node tetrahedral element (shown in Figure 3.4) is a higher order version of the three dimensional linear tetrahedral element. When compared to the four node tetrahedral element, the ten node tetrahedral element is better suited for and more accurate in modelling problems with curved boundaries (Moaveni, 2008).   

The Twenty Node Brick Element 

 The twenty node brick (shown in Figure 3.5) is a higher order version of the three dimensional eight node brick element. This element is more capable and more accurate for modelling problems with curved boundaries than the eight node brick element (Moaveni, 2008).  

Finite Element Analysis  

The Finite Element Method (FEM) is a powerful tool for the numerical procedure to obtain solutions to many problems encountered in engineering analysis. Structural, thermal and heat transfer, fluid dynamics, fatigue related problems, electric and magnetic fields, the concepts of FE methods can be utilized to solve these engineering problems. In this method of analysis, a complex region is discretized into simple geometric shapes called finite elements the domain over which the analysis is studied is divided into a number of finite elements. The software implements equations that govern the behavior of these elements and solves them all; creating a comprehensive explanation of how the system acts as a whole. These results then can be presented in tabulated or graphical forms. This type of analysis is typically used for the design and optimization of a system far too complex to analyze by hand. Created geometric models are transferred to the ANSYS program to be done FEA. Selection of element type on the mathematical model, creating the mesh form, determining the contact areas, boundary conditions, environment and material properties and the type of analysis have been made in the program interface.  

Distribution of 40 Tonnes of Loading on the Chassis 

CAD model of the chassis was transferred to ANSYS Workbench in stp file. This model is shown in CAD representation of the chassis was cut into small elements. Meshed chassis is illustrated in. Meshed model has 591861 nodes and 131557 solid elements. More information about the analysis is available in appendix. 

4 different forces and 2 supported regions were exerted on the chassis, these are presented in Table 4.1. 40 tonnes of container weight was applied on the sheets where container settles on the chassis. Also weights of the loader arms were hypothetically applied as 16677N distributed load. Rear axles and king pin regions were restricted in x-y and z directions. 

3 different forces and 4 supported regions were exerted on the mechanism 2 Forces were exerted to symbolize 40 tonnes of container weight (exerted as 20 tonnes at 2 different chain connection point) and other force was added to the system to represent own weight of the system . The feet where the legs touch to the ground were accepted as fixed point. Rear axles and king pin regions were restricted in x-y and z directions Totally 6 piston pressures were calculated by hand and applied on the modal4

40 Tonnes of Loading from the Hooks 

CAD model of the sidelifter was transferred to ANSYS Workbench in stp file. This model is shown in CAD representation of the sidelifter was cut into small elements. Meshed model has 1159314 nodes and 347437 solid elements More information about the analysis is available in appendix.

3 different forces and 4 supported regions were exerted on the mechanism. 2 Forces were exerted to symbolize 40 tonnes of container weight (exerted as 20 tonnes at 2 different chain connection point) and other force was added to the system to represent own weight of the system . The feet where the legs touch to the ground were accepted as fixed point. Rear axles and king pin regions were restricted in x-y and z directions Totally 6 piston pressures were calculated by hand and applied on the modal.

 Manufacturing of the Sidelifter 

For manufacture of the prototype, plain sheets are cut with CNC plasma machine, and then these sheets are welded together with gas metal arc process. Formed components are joined and auxiliary equipment are added together to compose the sidelifter. After assembly some make ups were applied such as painting operation. These processes are shown in Figure 4.18. St 52-3 N steel was used as main material of the sidelifter.  Steel grade    St 52-3 N is a low carbon, high strength structural steel which can be readily welded to other weldable steel. With its low carbon equivalent, it possesses good cold forming properties. Chemical composition of St 52-3 N quality steel given in Table 4.3 and mechanical properties are given in Table 4.4. 

Welding of the Sidelifter 

Gas metal arc welding was utilized as joining process between sheets. At this process metals were melted and joined by heating them with an arc established between a continuously fed filler wire electrode and the metals, as shown in Figure 4.21. Welding processes are utilized with the machine shown in Figure 4.22 and its properties are presented in Table 4.6.   

During the design steps, some geometry had dimensional tolerances due to some dimensional changes on sheets at welding processes because of thermal expansions. Because of solidification shrinkage and thermal contraction of the weld metal during welding, the workpiece has a tendency to distort such as in Figure 4.23. A view of a welding of the prototype is shown in Figure 4.24.