FEA Lab Manual-colored version-2 PDF

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(BSc. Mechanical Engineering UET, Lahore (City Campus)) (MSc. Mechanical Engineering UET, Lahore (City Campus))

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Preface The experiments to be performed in a laboratory should ideally be designed in such a way as to reinforce the understanding of the basic principles as well as help the students to visualize the various phenomenon encountered in different applications. The objective of this manual is to familiarize the students with practical skills, measurement techniques and interpretation of results. It is intended to make this manual self-contained in all respects, so that it can be used as a laboratory manual. In all the experiments, the relevant theory and general guidelines for the procedure to be followed have been given. It is suggested that the students should complete the computations, is the laboratory itself. However the students are advised to refer to the relevant text before interpreting the results and writing a permanent discussion. The questions provided at the end of each experiment will reinforce the students understanding of the subject and also help them to prepare for viva-voce exams.

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General Instructions to Students 

The purpose of this laboratory is to reinforce and enhance your understanding of the fundamentals of FEA Analysis. The experiments here are designed to demonstrate the applications of the basic FEA principles and to provide a more intuitive and physical understanding of the theory. The main objective is to introduce a variety of classical experimental and diagnostic techniques, and the principles behind these techniques. This laboratory exercise also provides practice in making engineering judgments, estimates and assessing the reliability of your measurements, skills which are very important in all engineering disciplines.

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Read the lab manual and any background material needed before you come to the lab. You must be prepared for your experiments before coming to the lab. In many cases you may have to go back to your fluid mechanics textbooks to review the principles dealt with in the experiment.

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Actively participate in class and don’t hesitate to ask questions. Utilize the teaching assistants. You should be well prepared before coming to the laboratory, unannounced questions may be asked at any time during the lab.

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Carelessness in personal conduct or in handling equipment may result in serious injury to the individual or the equipment. Do not run near moving machinery. Always be on the alert for strange sounds. Guard against entangling clothes in moving parts of machinery.

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Make your workplace clean before leaving the laboratory. Maintain silence, order and discipline inside the lab.

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Cell phones are not allowed inside the laboratory.

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Any injury no matter how small must be reported to the instructor immediately.

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Wish you a nice experience in this lab

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TABLE OF CONTENTS Preface....................................................................................................................................... 3 General Instructions to Students ............................................................................................ 4 List of Experiments .................................................................................................................. 7 List of Figures ........................................................................................................................... 8 1.

2.

3.

4.

LAB SESSION 1 ............................................................................................................... 9 1.1

Learning Objective: ..................................................................................................... 9

1.2

Apparatus .................................................................................................................... 9

1.3

Related theory ............................................................................................................. 9

1.4

Experimental procedure: ........................................................................................... 11

1.5

Observations & Calculations ..................................................................................... 11

1.6

Specimen Calculation................................................................................................ 11

1.7

Statistical Analysis .................................................................................................... 11

1.8

Conclusion:................................................................................................................ 11

LAB SESSION 2 ............................................................................................................. 12 2.1

Learning Objective: ................................................................................................... 12

2.2

Apparatus .................................................................................................................. 12

2.3

Related theory ........................................................................................................... 12

2.4

Experimental procedure: ........................................................................................... 13

2.5

Observations & Calculations ..................................................................................... 17

2.6

Specimen Calculation................................................................................................ 18

2.7

Statistical Analysis .................................................................................................... 18

2.8

Conclusion:................................................................................................................ 18

LAB SESSION 3 ............................................................................................................. 19 3.1

Learning Objective: ................................................................................................... 19

3.2

Apparatus .................................................................................................................. 19

3.3

Related theory ........................................................................................................... 19

3.4

Experimental procedure: ........................................................................................... 20

3.5

Observations & Calculations ..................................................................................... 21

3.6

Specimen Calculation................................................................................................ 22

3.7

Statistical Analysis .................................................................................................... 22

3.8

Conclusion:................................................................................................................ 22

LAB SESSION 4 ............................................................................................................. 23 4.1

Learning Objective: ................................................................................................... 23

4.2

Apparatus .................................................................................................................. 23 5

5.

4.3

Related theory ........................................................................................................... 23

4.4

Experimental procedure: ........................................................................................... 24

4.5

Observations & Calculations ..................................................................................... 27

4.6

Specimen Calculation................................................................................................ 28

4.7

Statistical Analysis .................................................................................................... 28

4.8

Conclusion:................................................................................................................ 28

LAB SESSION 5 ............................................................................................................. 29 5.1

Learning Objective: ................................................................................................... 29

5.2

Apparatus .................................................................................................................. 29

5.3

Related theory ........................................................................................................... 29

5.4

Experimental procedure: ........................................................................................... 30

5.5

Specimen Calculation................................................................................................ 35

5.6

Statistical Analysis .................................................................................................... 35

5.7

Conclusion:................................................................................................................ 35

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List of Experiments Experiment No. Experiment No. 1

Experiment No. 2

Experiment No. 3

Experiment No. 4

Experiment No. 5

Description To draw proper truss elements types (link types) and calculate and verify axial forces and nodal deflections in 2D (i.e. planar)/3D trusses. (1D elements, structural analysis) To specify proper beam elements types and calculate and verify deflections, bending and axial stresses at various points along the lengths of beams and drawing moment diagrams.(Beams deflections, structural analysis) To determine the natural frequencies and modes shapes of various single and multiple degrees of freedom systems of mechanical vibrations. (Modal/Vibration Analysis) To draw geometry and specify proper plane elements types for bodies assumed to be located in a plane and calculate and verify the stresses and strains distribution under given loads.(Plane stresses analysis) To specify proper thermal/fluid elements types and calculate and verify temperature distribution, thermal stresses and strains in 1D, 2D and 3D thermal or fluent bodies. (Fluid Analysis)

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List of Figures Figure 1-1 Truss problem........................................................................................................... 9 Figure 1-2 Results retrieved ..................................................................................................... 11 Figure 2-1 Beams ..................................................................................................................... 12 Figure 2-2 Beam supports ........................................................................................................ 13 Figure 2-3 Beam analysis problem .......................................................................................... 14 Figure 2-4 Line model ............................................................................................................. 15 Figure 2-5 X-section of Beam.................................................................................................. 15 Figure 2-6 X-assigned .............................................................................................................. 16 Figure 2-7 Loads applied ......................................................................................................... 17 Figure 2-8 Deformation ........................................................................................................... 17 Figure 2-9 Direct Stress ........................................................................................................... 18 Figure 2-10 Bending stresses in Beam..................................................................................... 18 Figure 3-1 Building vibrations .............................................................................................. 19 Figure 3-2 2-DOF Vibration system(Simplified) .................................................................... 20 Figure 3-3 Masses Creation ..................................................................................................... 20 Figure 3-4 Masses extruded ..................................................................................................... 21 Figure 3-5 springs added.......................................................................................................... 21 Figure 3-6 Modes ..................................................................................................................... 21 Figure 4-1 Finite element discretization: (a) unstructured (free) mesh; and (b) structured (mapped) mesh. ........................................................................................................................ 23 Figure 4-2 Support conditions in 2-D: (a) and (b) ineffective constraints; (c) effective constraint connectivity that can be described as a 2-D array, and it generally has better solution reliability .................................................................................................................... 24 Figure 4-3 Plane stress model wrench ..................................................................................... 24 Figure 4-4 Completed sketch of wrench .................................................................................. 25 Figure 4-5 Surface body generated .......................................................................................... 26 Figure 4-6 Setup for analysis ................................................................................................... 26 Figure 4-7 Meshed Model........................................................................................................ 27 Figure 4-8 Solved the model .................................................................................................... 28 Figure 5-1 Flow region definition: (a) internal flow and (b) external flow. ............................ 29 Figure 5-2 CFD Truck shape fluid analysis ............................................................................. 30 Figure 5-3 Truck model creation ............................................................................................. 31 Figure 5-4 Extruded truck body ............................................................................................... 31 Figure 5-5 Wheels created ....................................................................................................... 32 Figure 5-6 Enclosure for fluid.................................................................................................. 32 Figure 5-7 Meshed .................................................................................................................. 33 Figure 5-8 Setup for fluid boundary ........................................................................................ 33 Figure 5-9 Boundary conditions applied.................................................................................. 34 Figure 5-10 Results retrieved ................................................................................................... 34 Figure 5-11 Streamlines plot.................................................................................................... 35

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1. LAB SESSION 1 To draw proper truss elements types (link types) and calculate and verify axial forces and nodal deflections in 2D (i.e. planar)/3D trusses. (1D elements, structural analysis)

1.1 Learning Objective: At the end of this study, the student will be able to:   

To perform the analysis of any 2D and 3D trusses To identify the tension and compression of truss members Calculate axial forces in truss members

1.2 Apparatus PC with Ansys Workbench installed

1.3 Related theory Problem Description: Truss bridges can span long distances and support heavy weights without intermediate supports. They are economical to construct and are available in a wide variety of styles. Consider the following planar truss, constructed of wooden timbers, which can be used in parallel to form bridges. Determine the deflections at each joint of the truss under the given loading conditions.

Figure 1-1 Truss problem

Step 1: Start an ANSYS Workbench Project Launch ANSYS Workbench and save the blank project as “Woodtruss.wbpj.” Bars and Trusses 41 Step 2: Create a Static Structural (ANSYS) Analysis System Drag the Static Structural (ANSYS) icon from the Analysis Systems Toolbox window and drop it inside the highlighted green rectangle in the Project Schematic window to create a standalone static structural analysis system. 9

Step 3: Add a New Material Double-click (or right-click and choose Edit) on the Engineering Data cell in the above Project Schematic to edit or add a material. In the following Engineering Data interface which replaces the Project Schematic, click the empty box highlighted below and type a name, for example, “Douglas Fir,” for the new material. Select “Douglas Fir” from the Outline window, and double-click Isotropic Elasticity under Linear Elastic in the leftmost Toolbox window. Enter “1.31E10” for Young’s Modulus and “0.29” for Poisson’s Ratio in the bottom center Properties window. Click the Return to Project button to go back to the Project Schematic. Step 5: Create Line Sketch Click the Sketching tab and select Settings. Turn on Show in 2D and Snap under Grid options. Use the default value of “5 m” for Major Grid Spacing and “5” for Minor-Steps per Major. Click a start point and then an end point in the Graphics window to draw a line. Draw 13 lines as shown in the sketch below. After completion, click Generate to create a line sketch. Step 6: Create Line Body from Sketch Check off the Grid options under Settings of Sketching Toolboxes. Switch to the Modelling tab. Note that a new item named Sketch1 now appears underneath X-Y Plane in the Tree Outline. Select Lines from Sketches from the Concept drop-down menu. Step 7: Create a Cross Section Select a Cross Section of Rectangular from the Concept drop-down menu. A new item named Rect1 is now added underneath the Cross Section in the Tree Outline. In the Details of Rect1 under Step 8: Assign Cross Section to Line Body Select the Line Body underneath 1Part, 1 Body in the Tree Outline. In the Details of Line Body, assign Rect1 to the Cross Section selection. Click Close Design Modeller to exit the program. Dimensions, enter “0.06 m” for both B and H. Step 9: Launch the Static Structural (ANSYS) Program Double-click the Model cell to launch the Static Structural (ANSYS) program. Note that in the Details of “Line Body” the material is assigned to Structural Steel by default. Click to the right of the Assignment field and select Douglas Fir from the drop-down context menu. Step 10: Generate Mesh In the Details of “Mesh,” enter a fairly l...