Finite elements method assignment
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ENGR7961FiniteElementMethods-AssessmentI-Report1.docxENGR7961 Finite Element Methods
Assessment I - Report
Semester 1 201
Topic Coordinators: Dr Rami Al-Dirini
Due Date: 22nd of April 2021
Part 1: Simulating dog-bone tensile testing (10%)
As an FE engineer designing a product that uses rubber, you need to ensure that you have accurate data on the material properties. Therefore, you are provided with standard uniaxial tensile set testing (ASTM D412) data for Neoprene rubber (attached)
Task: Using the data provided in the attached excel sheet (Neoprene_tensile_data.xlsx) and the dimensions on Figure 1, you are required to develop an FE model for this experiment in order to calibrate your material properties. Use the template provided to report your FE process and results.
You are expected to explore the use of different elements and element order (linear or quadrilateral) while developing your model
Figure 1: dog-bone sample dimensions and coordinate system
70 mm
50 mm
16 mm
8 mm
5 mm
Part 2: Testing design robustness for a steel clamp.
You are part of an engineering team designing a steel clamp that supports 3-dimensional tensile loads. Given that the clamp will be supported by 2 bolts (as shown in Figure 2), as an FE engineer, you are required to assess the robustness of the design under the expected loads:
Loads: simulate a force with the following components:
Fx = -5 x 105 N
Fy = 0 N
Fz = 5 x 105 N
Bolt
Bolt
Figure 2: Clamp with bolt locations shown
Figure 3: side view of the clamp with coordinate system showing the x (red) and z (blue) axes.
Task:
Using the attached CAD file (CAD_Fitting.igs) and the information above, you are required to develop an FE model assess the robustness of this design to the expected loads. You may consider the concept of safety factor and the fact that the yield stress for this type of structural steel is 360 MPa.
You are expected to explore the use of different elements and element order (linear or quadrilateral) while developing your model.
Tips
Importing CAD geometry files:
Once the model shows on your screen, close the screen and return to ANSYS Workbench.
Defining Mesh Element Type, Size and Order:
Controlling element type:
Right click on the “Mesh” in the model tree and select “Insert” > “Method”
You can select the appropriate “Method” and “Element Order” in the “Details” panel on the left of the screen.
Notes:
Use “Tetrahedrons” to generate a mesh with tetrahedral elements and “Cartesian” to generate a mesh with hexahedral elements. [footnoteRef:1] [1: Alternatively, you can use “Hex Dominant” method, however, this tends to fail for some geometries. ]
Controlling element size:
Right click on the “Mesh” in the model tree and select “Insert” > “Sizing”
You can select the appropriate element size in the “Details” panel on the left of the screen.
Analysis settings: use default settings, ensuring that “large deflection” is “Off”.
Boundary conditions: the model should simulate a condition representative of the clamp being fixed by two bolts as below:
Use this template for the Cover Page of Your Report:
Flinders University
College of Science & Engineering
Assessment I - Report
As part of the topic
ENGR7961 Finite Element Methods
Report Prepared by:
Enter your name here
Student ID number: XXXXXXX
“I declare that this report only presents my independent work”
Your Signature Here
Submission Date: Enter date here
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Part 1: Simulating dog-bone tensile testing (10%) |
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Modelling Assumptions (you can add more rows as needed) |
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Assumption |
Justification |
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Material Properties |
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Young’s Modulus (MPa)* |
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Poison’s ratio |
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* Use the data from Neoprene_tensile_data.xlsx to calculate Young’s Modulus |
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CAD model annotated with loads and boundary conditions |
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Mesh convergence (you can add more rows as needed) |
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Element type |
Element order |
Number of elements |
Number of nodes |
Maximum deformation (mm) |
Maximum stress (MPa) |
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Tri |
Linear |
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Tri |
Quad |
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Quad |
Linear |
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Quad |
Quad |
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Mesh Convergence Plots for All Elements |
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FE Results |
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Details for converged model |
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Element type |
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Element Order |
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Number of elements |
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Number of nodes |
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Results |
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Maximum deformation in x-direction (mm) |
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Maximum deformation in y-direction (mm) |
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Maximum principal stress (MPa) |
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Maximum principal strains (mm/mm) |
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Plot for deformation field in y-direction (mm) – include scale/colour bar! |
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Plot for deformation field in y-direction (mm) – include scale/colour bar! |
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Plot for equivalent stress field (MPa) – include scale/colour bar! |
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Plot for equivalent strain field (mm/mm) – include scale/colour bar! |
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Validation - Comparison with experimental Data |
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Plot FE vs Experimental displacements |
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Plot FE vs Experimental Principal Stresses |
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Based on the above plots, comment on the validity of your model (i.e, will you be confident in using this model for simulating the final product design) |
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Discuss the limitations of your model for Neoprene rubber |
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Part 2: Testing design robustness for a steel clamp (15%) |
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Modelling Assumptions (you can add more rows as needed) |
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Assumption |
Justification |
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Material Properties |
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Young’s Modulus (MPa) |
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Poison’s ratio |
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CAD model annotated with loads and boundary conditions |
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Mesh convergence (you can add more rows as needed) |
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Element type |
Element order |
Number of elements |
Number of nodes |
Maximum deformation (mm) |
Maximum stress (MPa) |
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Tetrahedral |
Linear |
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Tetrahedral |
Quad |
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Hexahedral |
Linear |
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Hexahedral |
Quad |
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Mesh Convergence Plots for All Elements |
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FE Results |
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Details for converged model |
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Element type |
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Element Order |
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Number of elements |
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Number of nodes |
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Results |
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Maximum deformation in x-direction (mm) |
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Maximum deformation in y-direction (mm) |
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Maximum principal stress (MPa) |
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Maximum principal strains (mm/mm) |
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Plot for deformation field in y-direction (mm) – include scale/colour bar! |
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Plot for deformation field in y-direction (mm) – include scale/colour bar! |
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Plot for equivalent stress field (MPa) – include scale/colour bar! |
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Plot for equivalent strain field (mm/mm) – include scale/colour bar! |
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Based on the above plots, comment on the robustness of the designed clamp under the expected loads |
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Discuss the limitations of your model. |
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