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MECH 3130: Mechanics of Materials
Fall 2015
Laboratory Manual
Volume – II
Instructor
Dr. Peter Schwartz
Dr. Nels Madsen
Lab Teaching Assistants
Quang Nguyen: qzn0003@auburn.edu
Abhiram Pasumarthy rzp0025@auburn.edu
Jing Wu jzw0061@auburn.edu
Abdullah Fahim azf0030@auburn.edu
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CONTENTS
1. FINITE ELEMENT ANALYSIS OVERVIEW
3
2. ANALYSIS OF TRUSS – TUTORIAL
12
3. ANALYSIS OF TRUSS – EXERCISE
34
4. ANALYSIS OF BEAM – TUTORIAL
36
5. ANALYSIS OF BEAM – EXERCISE
45
6. 2D STRESS ANALYSIS AND SCF – TUTORIAL
46
7. 2D STRESS ANALYSIS AND SCF – EXERCISE
60
8. ANSYS-CAD INTERFACE & ANALYSIS – TUTORIAL
61
9. ANSYS-CAD INTERFACE & ANALYSIS – EXERCISE
73
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LAB # 8
Finite Element Analysis Overview
Source: ANSYS documentation
What is Finite Element Analysis (FEA)?
Finite element method is a numerical analysis technique for obtaining approximate solutions to a
wide variety of engineering problems. Usually the problem addressed is too complicated to be
solved satisfactorily by classical analytical methods. The finite element method produces many
simultaneous algebraic equations, which are generated and solved on a digital computer. The finite
element method originated as a method of stress analysis. Today finite element methods are used
to analyze problems of heat transfer, fluid flow, lubrication, electric and magnetic fields, and many
others. Finite element procedures are used in the design of buildings, electric motors, heat engines,
ships, airframes and spacecraft.
The word finite element method was first coined by Clough in 1960 in a paper on plane elasticity
problems. In the years since 1960 the finite element method received widespread acceptance in
engineering. With the advent of the digital computer, it opened a new avenue for solving complex
plane elasticity problems. The first commercial finite element software made its appearance in
1964.
The finite element method works by discretizing (breaking a real object into a large number of
small elements). The behavior of each element is readily predicted by set mathematical equations.
Then the computer adds up all the individual behaviors to predict the overall behavior of the actual
object. The word "finite" in finite element analysis comes from the idea that there are finite
numbers of elements in a model. This is in contrast to the classical approach (differential equation
method) where an infinitesimal element is considered for derivation of the governing equations.
To summarize, the finite element method satisfies the governing equations in an approximate or
average sense whereas classical methods insist on validity of the solution at each and every point
in the domain. The finite element method is employed to solve almost all physical systems.
Structural mechanics (stress analysis)
Mechanical vibration
Heat transfer - conduction, convection, radiation
Fluid Flow - both liquid and gaseous fluids
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Various electrical and magnetic phenomena
Acoustics
What is a Node?
A node is a coordinate location in space where the degrees of freedom (DOF) are defined. In the
context of stress analysis of structural members, the DOF represent the possible motion of a point
due to loading of the structure. The forces and moments are transferred between two adjacent
elements through a node.
What is an Element?
An element is the basic building block of a finite element model. There are several basic types of
elements. Typically, an element is bounded by the nodal points. Examples are solid brick and
tetrahedron elements for 3 dimensional problems, Quadrilateral and triangular elements for 2
dimensional problems, beam and truss elements are typical line elements. Also the elements may
be straight in shape or curved.
Some General Type of Elements in ANSYS:
1. LINK 1 (or 2-D Spar or Truss):
“LINK 1” is the ANSYS name of the element.
“2-D Spar or Truss” is the type of the element.
LINK1 can be used in a variety of engineering applications. Depending upon the application,
you can think of the element as a truss, a link, a spring, etc. The 2-D spar element is a uniaxial
tension-compression element with two degrees of freedom at each node: translations in the
nodal x and y directions. As in a pin-jointed structure, no bending of the element is considered.
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