ANSYS is an engineering simulation software founded by John Swanson. It develops CAE products like ANSYS Mechanical and ANSYS Multiphysics, which are used for numerically solving mechanical problems involving structural analysis, heat transfer, and fluid dynamics. These products allow modeling using finite elements and solving the resulting equations to analyze how engineering components will react to real-world forces, temperatures, pressures and other physical effects.
2. • Engineering simulation software founded by software engineer John Swanson.
• Developed a range of computer-aided engineering (CAE) Products, it is
perhaps best known for its ANSYS mechanical and ANSYS multiphysics
products.
• Ansys mechanical and ANSYS multiphysics software are non exportable
analysis tools.
• These are general purpose finite element modeling packages for numerically
solving mechanical problems, including static/dynamic structural analysis both
linear/non linear), heat transfer and fluid problems
contd...
ABOUT ANSYS
3. About Analysis
Process of analyzing a structure to the externally
applied loads( Pressure, Force, Temperature)
4. Basic Terminologies-Structural analysis
• Stress
• Strain
• Poisson ratio
• Hook's law
• Young's modulus
• Bending moment
• Shear force
• Stress strain curve for various materials
• Linear
• Nonlinear
• Isotropic vs. anisotropic vs. orthotropic
5. Stress
When some external system of forces or
loads act on a body, the internal forces
(equal and opposite) are set up at various
sections of the body, which resist the
external forces. This internal force per unit
area at any section of the body is known as
unit stress or simply stress
Stress, =σ P/A
6. Strain
When a system of forces or loads act on a body,
it undergoes some deformation. This
deformation per unit length is known as unit
strain or simply a strain. It is denoted by a
Greek letter epsilon (ε).
Strain, ε = δl / l
δl = ε.l
7. Displacement
A change in the configuration of a continuum body
results in a Displacement. The displacement of a
body has two components: a rigid-body
displacement and a deformation. A rigid-body
displacement consists of a simultaneous
translation and rotation of the body without
changing its shape or size. Deformation implies
the change in shape and/or size of the body from
an initial or undeformed configuration to a
current or deformed configuration
8. Shear Stress
When a body is subjected to two equal and
opposite forces acting tangentially across the
resisting section, as a result of which the body
tends to shear off the section, then the stress
induced is called shear stress.
Shear stress, τ = Tangential force
Resisting area
9. Shear Strain
When a body is subjected to two equal and
opposite forces acting tangentially across the
resisting section, as a result of which the body
tends to shear off the section corresponding
strain is known as shear strain.
10. Shear Force
In static equilibrium, the internal force has a
magnitude equal to opposite in direction and
parallel to the cross-section. is called the
shear force.
F-Shear Force
11. BENDING MOMENT
• The bending moment at the cross section of a
beam may be defined as the algebric sum of
the moment of the forces to the right or left
of the section
• The bending moment at the cross section of a
beam may be defined as the algebric sum of
the moment of the forces to the right or left
of the section
12. DEGRESS OF FREEDOM
• Minimum no of independent co
ordinates required to determine
completely the positions of all parts of a
system at a given instant time
• Minimum no of independent co
ordinates required to determine
completely the positions of all parts of a
system at a given instant time
13. Young’s modulus And Poisson’s Ratio For Some Materials
Materials Young’s Modulus Poisson’s Ratio
Steel 2.1e5 0.3
Cast Iron 1.20e5 0.28
Wrought Iron 1.90e5 0.3
Aluminium 0.70e5 0.35
Aluminium Alloy 0.75e5 0.33
Brass 1.10e5 0.34
Bronze 1.20e5 0.34
Copper 1.20e5 0.34
Copper Alloy 1.25e5 0.33
Magnesium 0.45e5 0.35
Titanium 1.10e5 0.33
Glass 0.60e5 0.22
Rubber 50 0.49
Concrete 0.25e5 0.15
14. Truss element
• The truss elements are the part of a truss
structure linked together by point joints,
which transmit only axial force to the
element
• The truss elements are the part of a truss
structure linked together by point joints,
which transmit only axial force to the
element
15. GLOBAL & LOCAL AXES
GLOBAL :
Global axes are defined for the entire
system. They are same in direction for all the
elements even though the elements are
differently oriented
LOCAL :
Local axes are established in an
element. Since it is the element level, they
change with the change in orientation of the
element. The direction differs from element to
element
16. Need for Analysis
•To reduce product
development cycle time
•To reduce the cost of
product
•Idle time reduction
•Better design and
Alternate materials
•To reduce material
wastage
17. Types of Methods
• Mathematical approach
• Physical model
• Numerical method
18. Introduction to FEM & FEA
• FEM-Finite element method
• FEA –Finite element analysis
19. FEM
• Finite element method of structural analysis
was created by academic and industrial
researches during 1959’s and 1960’s
• Theoretical approach.
• Examples
Euler's rule, LaGrange method,
Newton raphson method, Fourier series
20. Nature of FEM
• Force method (Forces unknown)
Strain energy method
Consistent deformation method
Matrix flexibility method
Clayperons theorem of 3 moments
• Displacement method (Displacements unknown)
Kanis method
Slope deflection method
Matrix stiffness method
Moment distribution method
FEM
21. FEA
FEA-
simulate loading conditions on design &
determine design response to these
conditions
The design is modeled using discrete elements
called elements
The sum of response of all elements in the
model gives the response of design
22. Problem types in FEA
• Boundary value problem-static and steady
state analysis
• Initial value problem-fluid flow
• Eigen value problem-Modal analysis, vibration
and natural frequency
• Boundary initial value problem-forced
vibration, transient and dynamic analysis
23. Linear vs. Non linear
• What is linear analysis?
• What is non linear analysis?
• Types of non linearity
• When should we do a non linear analysis?
24. 24/50
16.1.1 What is a Nonlinear
Structure
Displacements
Forces
Displacements
Forces
25. 25/50
16.1.2 Causes of Nonlinearities
• Geometric Nonlinearity
• Material Nonlinearity
• Status Nonlinearity
35. 35/50
16.3.2 Consistent Stiffness Matrix
• Tangent stiffness
• Additional stiffness due to deformation (geometric
change)
• Additional stiffness due to stress stiffening
• Additional stiffness due to change of loading
direction.
aσuinc
KKKKK +++=
36. 36/50
16.3.3 Load Steps, Substeps, and
Equilibrium Iterations
Substeps
Time
Load
Load step 2
Load step 1
D = D4
F = F4
Actual
respons
e
1
2
3
4
D1 D2 D3
F1
F2
F3
37. 37/50
16.3.4 Concepts of Time
• The ends of load steps or substeps can be
identified by time.
• For dynamic problem, time is used as a
real-world clock.
• For static problem, time is used as a
counter.
38. 38/50
16.3.5 Automatic Time Stepping
• For nonlinear problem, the user-input
∆t is used as initial incremental time.
• ANSYS adjusts ∆t automatically
according to the convergence
behavior of the solution.
45. 45/50
16.4.3 Load Step Time (TIME)
• TIME specifies the time at the end of
the following load step.
46. 46/50
16.4.4 Number of Substeps
(NSUBST, DELTIM)
• NSUBST specifies number of substeps for
the following load step.
• DELTIM specifies time for each substep for
the following load step.
• The two commands are equivalent, i.e.,
NSUBSTDELTIMTIME ×=
NSUBST, NSBSTP, NSBMX, NSBMN, Carry
DELTIM, DTIME, DTMIN, DTMAX, Carry
53. 53/50
16.5.2 Time Step Prediction
Based on Contact Status
(SOLCONTROL)
• The second key of SOLCONTROL
command is to ask ANSYS to adjust
time steps according to contact
status.
SOLCONTROL, Key1, Key2
54. 54/50
16.5.3 Number of Equilibrium
Iterations (NEQIT)
• NEQIT specifies the number of
iterations beyond which ANSYS would
start another “attempt”.
62. 62/50
16.5.11 Time Integration Effects
(TIMINT, TINTP)
• TIMINT turns ON/OFF transient
effects.
• The parameter GAMMA of TINTP
command can be used to introduce a
“numerical damping”.
TIMINT, Key, Lab
TINTP, GAMMA, ...
63. 63/50
16.5.12 Stop Control (NCNV)
• NCNV specifies the stop (failure)
conditions of the computation.
NCNV, KSTOP, DLIM, ITLIM, ETLIM, CPLIM
68. Static analysis
• Analysis of a structure for various loads under static condition i.e.
component under rest when loads are applied
Examples
Holding devices-Clamp or fixture analysis
Types
Linear analysis
Non linear analysis
69. Dynamic analysis
• Analysis of a structure for various loads under
Dynamic condition i.e. component is in motion when
loads are applied or time varying loads
Examples
Suspension systems of a vehicle
Types
Linear analysis
Non linear analysis
73. Structure Idealization
• Process of discritization of a structure into
element and nodes
• Infinite no of D.O.F to Finite D.O.F
Types of discritization
Natural
Artificial
74. FEM
• Nodes
• Elements
Types of elements
1D-Line element(Min 2 nodes)
2D-Plane element (Area-Min 4 node)
3D-Solid element (Volume-min 8 nodes)
75. EXAMPLES FOR FINITE ELEMENT
ONE DIMENSIONAL ELEMENTS :
TRUSS ELEMENTS
BAR, BEAM ELEMENTS
TWO DIMENSIONAL ELEMENTS :
TRIANGULAR ELEMENTS
RECTANGULAR ELEMENTS
THREE DIMENSIONAL ELEMENTS
TETRAHEDRAL ELEMENTS
HEXAHEDRAL ELEMENTS
79. H and P versions
H and P improve the accuracy of the fem
In h versions the order of polynominal approximation
for all elements kept constant and the no of elements
increased.
In P version the no of elements are maintained
constant and the order of polynominal approximation
of element is increased
83. List of other CAE softwares
• Msc Nastran
• Patran
• Ls dyana
• Addams
• Comsol
• Fluent
• gambit
• Star CD
• Hyper form
• Pam crash
• Mat lab
• ANSA