Figure1.1: Finite element Truss Model 1
Figure 1.2: Meshed FE Model
Figure1.3: Meshed FE Model with Load Constraints
DISCUSSION Element Type Chosen for Meshing (Link 2D Spar 1): The element used for the analysis of the FE model is the 2D spar 1 of the Link 1 element type. 2D Spar 1 can be used extensively in 2Dimensional and one dimensional truss analysis, link analysis, etc. The Link 2D Spar 1 element is uniaxial, that is, deformation is analysed along one axis. The element was used in the analysis of this truss because of its elements’ uniaxial tension-compression feature and nodes degree of freedom, each node undergoing a translation along x-y direction. One of the uniqueness of this element type is the disregarding of any bending of the element, just like that of a pin-jointed structure.
Figure 1.4: Element Type dialog box Real Constant: The real constant defines the cross sectional area of the model.
Figure 1.5: Real Constant Dialog box 3
Material Model: The material Model used in this analysis is the Structural Linear Elastic Isotropic material model. This analysis is categorised as static structural analysis. It analyses the effect of a steady loading conditions, externally applied loads and pressure, steady state inertia forces (e.g. gravity), imposed displacement, etc. This analysis is employed to discover the displacement, stress, strain and forces in structural components. The model material is considered Linear because the material property of the model requires a non thermal analysis and requires a sole iteration. Elastic: The material returns to its original size after the applied force is removed, provided the stress does not exceed the material yield stress. It is termed isotropic due to the homogeneity of the material across the whole truss system. The Young’s modulus (EX = 170x103 MPa) and the Poisson’s ration (PRXY = 0.3) used defines the property of the material used. This is required for the displacement and stress-strain analysis of the truss system.
Figure1.6: Material Model Dialog Box The material model can be accessed for programming and definition of the material model behaviour, through clicking: Preprocessor >Material Props >Material Models > Structural >Linear >Elastic >Isotropic >Define EX (Young’s Modulus) and PRXY (Poisson’s ratio)
ANALYSIS OF THE FINITE ELEMENT MODEL UNDER THE GIVEN LOADING CONDITIONS The FE model with respect to the given dimension and loading conditions was created using the 2D tools from the analysis software (ANSYS) and the material properties of the model. The material properties used are modulus of elasticity (E = 170 x 103 MPa), Poisson’s ratio (v = 0.3); and the Active Coordinate systems of the model, to generate the keypoints and making the model by creating a connecting line. After the creation of the model and all the above parameters satisfied, the model was meshed with a mesh element number set to one. This is shown in figure 1.1, 1.2 and 1.3 above. The model is then restrained at keypoint 1 (Left edge of the truss) with all degrees of freedom equal to zero (DOF=0), followed by another restraint of the model along Y direction at keypoint 10 and 11, (DOF along Y axis arrested) due to the roller support. At keypoints 3, 4, and 5 is affixed Loads along negative Y direction (-Y–direction) with magnitude of 78.48 N, 49.05N and 39.24 N, respectively. This is shown figure 17, 18 and 19. From the analysis result, shown in table 1.2, the maximum displacement along x direction (UX) is 0.10431E-09 and is located at joint 12. The maximum displacement of the model along Y direction (UY) is -0.24106E-09 and is located at Joint 3. Considering the displacement result, it is...