ME 478 Introduction to Finite Element Analysis

Transcription

1 ME 478 Introduction to Finite Element Analysis Instructor: Dr. Alexander Veress Office Hours: Tues. 10:00 11:20 a.m. MEB 309 TA: Michael Au Yeung Office Hours: Tue. and Wed. 1:30-3:00 p.m. MEB 236

2 Finite Element Analysis ME 478A University of Washington, Seattle Fall Quarter 2013 Lecture: MEB 242 Time: M, T, Th 11:30-12:20 am Lab: MEB 231 Time: F 11:30-12:20 Website: GoPost:

3 Lecture/Lab Topic Book Readings Assign Due Thurs Sept. 25 Introduction to Finite Elements Chapter 1 Lab 26 ANSYS tutorial Mon Sept. 29 Direct Assembly Springs pp Tues 30 Direct Assembly Springs pp HW 1 Thurs Oct. 2 Direct Assembly Bars pp Lab 3 pp Mon Oct. 6 Minimum Potential Energy pp HW 2 Tues 7 Minimum Potential Energy example HW 1 Thurs 9 Minimum Potential Energy example Lab 10 pp Mon Oct. 13 2D Truss Formulation Local Global Coordates pp Tues 14 2D Truss pp HW 3 Thurs 16 3D Truss/Special Topic pp HW 2 Lab 17 pp Mon Oct. 20 Bending pp Tues 21 Torsion pp HW 4 Thurs 23 Torsion and Special Topic pp HW 3 Lab 24 Isoparametric Formulation pp Mon Oct. 27 Isoparametric Formulation pp Tues 28 Isoparametric Formulation HW 5 HW 4 Thurs 30 Midterm Exam Lab 31 Mon Nov. 3 2D Plane Stress/strain pp Tues 4 2D Plane Stress/strain pp HW 6 Thurs 6 2D Plane Stress/strain Example HW 5 Lab 7 Mon Nov. 10 3D Stress Analysis pp Tues 11 Veteran's Day HW 7 Thurs 13 3D Stress Analysis and Special Topic pp HW 6 Lab 14 Mon Nov. 17 Heat Transfer pp HW 8 Tues 18 Heat Transfer pp HW 7 Thurs 20 Heat Transfer and Special Topic pp Lab 21 Mon Nov. 24 Vibration pp Tues 25 Vibration pp HW 8 Thurs 27 Thanksgiving Fri 28 Thanksgiving Mon Dec. 1 Vibration and Special Topic pp Tues 2 Electrostatics Thurs 4 Lab/Review 5

4 Expectations Homework Policy: All assignments must be handed in before class starts. If you used MATLAB or other software to complete your homework, print out the code and results and circle your answer. Late homework will be accepted if and only if arrangements are made by the evening before it is due. Lab Policy: There will be lab sessions for this course where you will run guided tutorials with the TAs. Must show TA your work to receive credit. Project Report Policy: This course has projects that require you to run commercial FEA software and write a memo report on the results Collaboration Policy: You may discuss projects and homework with your fellow students, and even collaborate on the solution, but you must list on the report or homework the name of the person(s) that collaborated with you on the effort. You may not copy someone else s reports, data, or figures. There is a zero-tolerance for cheating or plagiarism. Grading: 1) Homework 20% 2) Labs 15% 3) Projects 30% 4) Midterm Exam 15% 5) Final Exam 20% Exams: Tests will be closed book and closed notes.

5 Project Grading for Project Reports Introduction: 15 Very brief background and purpose for the model. Methods: 25 Indicate the elements used, the boundary conditions/loads assigned, and how the model was meshed (number of nodes, node seeding if any, etc.). Results (and Appendices): Analysis of the modeling data is complete, clear, and correct. 20 Results in figures, graphs, and tables are accurate and important features are described in the text. Captions for each figure describe results of figure. 10 Format of graphs and tables is professional looking. Appropriate units are indicated. Captions to describe the contents of the graph or table. Reference to graphs, tables, and appendices are made in the report. 10 Discussion: 20 Take a critical view of results. Are the results expected? Compare with simplified analytical solutions. Conclusion: 100

6 Typical Class FEM theory Example problems Practical considerations

7 Remote Desktop

8 Remote Desktop Start Page

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10 Storing your work Remote desktop files will be deleted every couple of days. Obtain U drive storage online-storage/u-drive-central-file-storage-forusers/

11 Storing your work on U drive

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14 When that doesn t work, open WinSCP from the start page.

15 When that doesn t work, open WinSCP from the start page.

16 When that doesn t work, open WinSCP from the start page.

17 Finite Element Analysis Allows for the stress/strain/heat transfer analysis of complex geometries for which there is no analytical solution. Allows for defining complex materials such as composites.

18 Finite Element Analysis Grew out of aerospace industry Post-WW II jets, missiles, space flight Need for light weight structures Required accurate stress analysis Paralleled growth of computers

19 Examples #1 Modeling complex geometries

20 Examples #2 Modeling complex contact problems

21 Examples #3 Modeling composite materials

22 Head of the femur Biological Examples Bones of the forearm.

23 Biological Examples Left Ventricle modeling the heart cycle

24 Biological Examples Modeling considerations of modeling of Left Ventricle over the heart cycle.

25 Biological Examples Modeling considerations of modeling of Left Ventricle over the heart cycle. What is the material? What are the boundary conditions? What can you ignore?

26 Biological Examples Modeling considerations of modeling of Left Ventricle over the heart cycle. What is the material? Orthotropic often modeled as isotropic. A B What are the boundary conditions? LV pressure What can you ignore? Intrathoracic pressure

27 FEM Based Image Registration A pair of 3-D MRI image data sets representing two deformation states with a known deformation map were needed. (X) Deformation map Template Image end-systole Target Image end-diastole

28 Biological Examples Image registration of cardiac cycle

29 Biological Examples Hypertension induced hypertrophy

30 Components of an FEM Model Descritization of model body by dividing it into a system of many smaller bodies or elements interconnected at points common to two or more elements (nodes ). Nodes locations for solution of discretization problem in FEM. Element connectivity of the nodes make up the element.

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32 Typical FEM Analysis Creation of the mesh from geometric definition. CAD/CAM output Meshing iges, dxf, stl surface definitions Biological Applications Segmentation of medical images. High resolution images, typically CT and MRI.

33 Typical FEM Analysis Pre-processing mesh creation, material and loading definitions. Ansys has pre-processing built in. Abaqus has pre-processing built in. Preview (FEBio.org) TrueGrid ( LSPrePost (lstc.com) AutoFEM ( Requires AutoCAD

34 Analysis Import mesh into finite element analysis package. ANSYS start analysis. Abacus start analysis. Command line FEBio.exe i mesh.feb lsdyna.exe i mesh.k NIKE3d.exe i=mesh.n