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Simulations in Ansys Primož Drešar, FS UL
Basic steps in building numerical
simulation • Analysis are performed in following steps
– Building of geometry(Pre Processing)
– Setting of physical parameters
– Choosing numerical method (Pre Processing)
– Meshing and discretization (Pre Processing)
– Solving
– Interpreting results (Post Processing)
Ansys software
• Using Workbench
Material properties
Geometry
Meshing
Results
Project window
Example I: Structural Mechanics
• Simple 1-D stress-strain relation:
σ=𝐹
𝐴= 𝐸
∆𝑙
𝑙
- Example of dynamic differential equation for beam:
𝐸𝐼𝜕4𝑤
𝜕𝑥4+ ρA𝑤 = 𝐹𝑧
- Example of Hamilton principle (basis for FEM):
Example I: Structural Mechanics
– Static structural example: Applying torque on a key.
I. Step: Importing geometry
Boundary Conditions (BC)
• Cartesian Coordinate System
• Degrees of Freedom
Example I: Structural Mechanics
II. Step: Modeling of Finite Element mesh
Mesh topology is important!
Example I: Structural Mechanics
• Setting Analysis
– Material properties
– Boundary Conditions
– Initial Conditions
Results (post processing)
-Napetosti
-Deformacije
-Specifične deformacije
Interpretating results
• What does our result mean?
• How close is numerical result to real experimental
measurement?
• Numerical error.
• Can we do it wothout simulations?
• Interpretating and validating a result is important!
Example II: Computational fluid
dynamics (CFD) Water flow through pipe junction
Inlet speed: 5 m/s
Outlet: relative pressure: 0 Pa
inlet
outlet
Program is using discretisized functions derived from
Navier- Stokes – equations.
• Finite Difference Method
• Finite Volume Method
• Metoda Element Method…
Example II: Computational fluid
dynamics (CFD) • Importing Geometry
Using Ansys Workbench
Example II: Computational fluid
dynamics (CFD) • Meshing
– Taking into account mesh topology near wall
Using inflation layers near wall.
Example II: Computational fluid
dynamics (CFD) • Setting parameters and boundary conditions
- Ansys CFX
Static flow
Example II: Computational fluid
dynamics (CFD) • Interpretating results (CFX-post)
Results:
• Velocity
• Streamlines
• Pressure
