Monday, August 28, 2023

How to define porosity in Ansys CFX ?

 ANSYS CFX is another software for computational fluid dynamics (CFD) that can also simulate various phenomena involving fluid flow, heat transfer, and chemical reactions. Similar to ANSYS Fluent, ANSYS CFX can also model porous media, such as packed beds, filter papers, perforated plates, etc

To define porosity in ANSYS CFX, you need to specify a domain in which the porous media model is applied and the pressure loss in the flow is determined by your inputs. There are two approaches to set up the porous media model. 

In addition to the source term in the momentum equation, you also need to define the porosity value for the porous domain. The porosity is a dimensionless quantity that indicates the fraction of the domain volume that is occupied by fluid. The porosity affects the calculation of material properties, heat transfer, reaction source terms, and body forces in the porous medium. You can enter a constant value for the porosity or use a user-defined function (UDF) to specify a spatially varying porosity

To define porosity and resistance coefficients in ANSYS CFX using the graphical user interface (GUI), you can follow these steps:

  • Go to Domain panel and select the domain that you want to model as porous.
  • Enable Porous Media option and click Edit.
  • In the Porous Media panel, enter the value for porosity or select UDF option if you have a UDF for porosity.
  • Select either Standard or Power-Law option for Resistance Formulation.
  • Enter the values for resistance coefficients or select UDF option if you have a UDF for resistance coefficients.
  • Click OK to close the Porous Media panel and Apply to close the Domain panel.

To define porosity and resistance coefficients in ANSYS CFX using text commands (TCL), you can follow these steps:

  • Enable TCL mode by using the command: tcl
  • In TCL mode, type set domain-name [get "Domain:domain-name"] where domain-name is your domain name.
  • Type set domain-name.Porous Media = On to enable Porous Media option.
  • Type set domain-name.Porosity = value or set domain-name.Porosity = "UDF:udf-name" where value is your porosity value or udf-name is your UDF name for porosity.
  • Type set domain-name.Resistance Formulation = "Standard" or set domain-name.Resistance Formulation = "Power-Law" to select Resistance Formulation option.
  • Type set domain-name.Resistance Coefficients = "value1 value2" or set domain-name.Resistance Coefficients = "UDF:udf-name" where value1 and value2 are your resistance coefficients or udf-name is your UDF name for resistance coefficients.
  • Type end to exit from TCL mode.

For more information and examples on how to define porosity in ANSYS CFX, you can refer to these sources:

You can also watch this video that demonstrates how to simulate flow through porous media using ANSYS CFX:

How to define porosity in Ansys Fluent ?

 ANSYS Fluent is a software for computational fluid dynamics (CFD) that can simulate various phenomena involving fluid flow, heat transfer, and chemical reactions. One of the features of ANSYS Fluent is the ability to model porous media, such as packed beds, filter papers, perforated plates, etc

To define porosity in ANSYS Fluent, you need to specify a cell zone in which the porous media model is applied and the pressure loss in the flow is determined by your inputs. There are two approaches to set up the porous media model:

In addition to the source term in the momentum equation, you also need to define the porosity value for the porous cell zone. The porosity is a dimensionless quantity that indicates the fraction of the cell volume that is occupied by fluid. The porosity affects the calculation of material properties, heat transfer, reaction source terms, and body forces in the porous medium. You can enter a constant value for the porosity or use a user-defined function (UDF) to specify a spatially varying porosity

To define porosity and resistance coefficients in ANSYS Fluent using the graphical user interface (GUI), you can follow these steps:

  • Go to Cell Zone Conditions panel and select the cell zone that you want to model as porous.
  • Enable Porous Zone option and click Edit.
  • In the Porous Zone panel, enter the value for porosity or select UDF option if you have a UDF for porosity.
  • Select either Standard or Power-Law option for Resistance Formulation.
  • Enter the values for resistance coefficients or select UDF option if you have a UDF for resistance coefficients.
  • Click OK to close the Porous Zone panel and Apply to close the Cell Zone Conditions panel.

To define porosity and resistance coefficients in ANSYS Fluent using the text user interface (TUI), you can follow these steps:

  • Enable the use of parameters in TUI by using the command: /define/parameters/enable-in-TUI? yes
  • In the TUI, type /define/boundary-conditions/set/fluid
  • Select the appropriate cell zone by typing its name and hitting Enter.
  • Type y to enable Porous Zone option.
  • Enter the value for porosity or type udf if you have a UDF for porosity.
  • Type standard or power-law for Resistance Formulation.
  • Enter the values for resistance coefficients or type udf if you have a UDF for resistance coefficients.
  • Type end to exit from fluid boundary conditions.

For more information and examples on how to define porosity in ANSYS Fluent, you can refer to these sources:

You can also watch these videos that demonstrate how to simulate flow through porous media using ANSYS Fluent:


#12steps Video Tutorial Ansys Transient Thermal - How to define different temperatures on various elements on one geometry ?

First of all, U need to know what are APDL commands and what to use for. 

 The IC command in Ansys APDL is used to specify initial conditions at nodes for a static or transient analysis . It allows you to define the initial values of the degrees of freedom, such as displacements, rotations, temperatures, magnetic potentials, etc. The syntax of the IC command is:

IC, NODE, Lab, VALUE, VALUE2, NEND, NINC

where:

  • NODE is the node at which the initial condition is applied. You can use ALL to apply to all selected nodes, P to enable graphical picking, or a component name.
  • Lab is the degree-of-freedom label for which the initial condition is specified. You can use ALL to apply to all appropriate labels.
  • VALUE is the initial value of the degree of freedom. It defaults to the program default for that degree of freedom (0.0 for structural analysis, TUNIF for thermal analysis, etc.).
  • VALUE2 is the second-order degree of freedom value, mainly used for non-structural DOF where VELX can’t be used. It defaults to the program default for that degree of freedom (0.0 for structural analysis).
  • NEND and NINC are optional arguments that specify the same initial condition values at a range of nodes from NODE to NEND (defaults to NODE), in steps of NINC (defaults to 1).

Some notes and examples of using the IC command are:

For example, to apply an initial temperature of 100°C to all selected nodes, you can use:

IC, ALL, TEMP, 100

To apply an initial displacement of 0.01 m in the x-direction and an initial velocity of 5 m/s in the y-direction to node 5 and node 10, you can use:

IC, 5, UX, 0.01
IC, 5, VELY, 5
IC, 10,, , , 10

You can find more information about the IC command and other Ansys APDL commands in the Mechanical APDL Command Reference . You can also visit the Ansys Learning Forum  to ask questions and learn from other users. I hope this helps you understand the IC command better. 😊

Sunday, August 27, 2023

What is better? SpaceClaim or Design Modeler in Ansys ?

 SpaceClaim is a 3D CAD modeling software that runs on Microsoft Windows and is developed by SpaceClaim Corporation, which was acquired by Ansys in 2014². SpaceClaim allows you to quickly create, edit, or modify imported geometry without the complexity associated with traditional CAD systems. You can use SpaceClaim for various purposes, such as design and concept modeling, reverse engineering, 3D printing, model preparation for simulation and manufacturing, and more⁴.


SpaceClaim uses direct modeling techniques that let you manipulate the geometry with simple gestures, such as pull, move, fill, and combine. You can also add constraints and parameters to your sketches and save them with a block recording function. SpaceClaim can import and export various file formats, such as STEP, IGES, STL, etc⁵. SpaceClaim is integrated with Ansys Simulation packages as a built-in 3D modeler².

Source: 

(1) Ansys SpaceClaim: Tips and Tricks | Ansys Virtual Academy. https://www.youtube.com/watch?v=ZI02A1cS8ME.

(2) Ansys SpaceClaim | 3D CAD Modeling Software. https://www.ansys.com/products/3d-design/ansys-spaceclaim.

(3) SpaceClaim - Wikipedia. https://en.wikipedia.org/wiki/SpaceClaim.

(4) What's New in Ansys SpaceClaim 2020 R2. https://www.youtube.com/watch?v=faAKd_aOq6w.

(5) ANSYS Discovery SpaceClaim - ANSYS 19 Overview. https://www.youtube.com/watch?v=Dz-k2f1Taq4.

(6) ANSYS SpaceClaim: Everything to Know | Explore the Future of .... https://sunglass.io/ansys-spaceclaim/.

(7) Ansys SpaceClaim Reviews 2023: Details, Pricing, & Features - G2. https://www.g2.com/products/ansys-spaceclaim/reviews.

(8) https://ketiv.com/academy/ansys-virtual-academy/.


What is better: Ansys SpaceClaim or Ansys Design Modeler?

There is no definitive answer to which tool is better, as it may depend on your preferences, needs, and use cases. However, I can provide you with some information and comparisons based on the web search results that I have found.

- ANSYS DesignModeler (DM) and ANSYS Discovery SpaceClaim (SC) are both 3D modeling tools that can be used for creating and modifying geometry for simulation purposes¹.

- DM and SC use different geometry modeling kernels: DM uses Parasolid, while SC uses ACIS². This means that moving data between DM and other tools that use Parasolid (such as SOLIDWORKS) is easier than moving data between SC and those tools, as there is no need for translation². However, SC can also import and export various file formats, such as STEP, IGES, STL, etc³.

- DM has a history tree that records the sequence of operations performed on the geometry, while SC does not have a history tree by default (although it can be enabled with an optional feature)². This means that DM allows you to easily modify the parameters and constraints of the geometry at any stage, while SC requires you to use the block recording function to save and replay the operations⁴.

- SC has a more intuitive and user-friendly interface than DM, as it uses direct modeling techniques that allow you to manipulate the geometry with simple gestures such as drag, pull, move, etc³. SC also has more advanced features such as repair, simplify, optimize, etc., that can help you prepare the geometry for simulation faster and easier³.

- Both DM and SC have their own advantages and disadvantages, and you may need to use both of them depending on the situation. For example, you may want to use DM for parametric design and optimization, and use SC for complex geometry creation and modification².

Source:

(1) Design Modeler Vs SpaceClaim - Ansys Learning Forum. https://forum.ansys.com/forums/topic/design-modelller-vs-spaceclaim/.

(2) When DesignModeler is a better choice than SpaceClaim. https://forum.ansys.com/forums/topic/when-designmodeler-is-a-better-choice-than-spaceclaim/.

(3) Compare ANSYS DesignModeler vs ANSYS Discovery SpaceClaim. https://comparisons.financesonline.com/ansys-designmodeler-vs-ansys-discovery-spaceclaim.

(4) Compare Ansys Discovery vs Ansys SpaceClaim 2023 | Capterra. https://www.capterra.com/simulation-software/compare/245795-124168/Ansys-Discovery-vs-Ansys-SpaceClaim.

Saturday, August 26, 2023

#12steps Video Tutorial - Conjugate Heat Transfer on Ansys Fluent

 This is the first episode of 12 steps video's tutorials. I hope You like it :) 

First U need to know what is Conjugate Heat Transfer. 

Conjugate heat transfer is a type of heat transfer analysis that involves both solids and fluids. It takes into account the effects of conduction in solids and convection in fluids, as well as the interactions between them at the interface. Conjugate heat transfer is important for many engineering applications, such as cooling of electronic devices, heat exchangers, combustion chambers, and solar collectors. ¹²


Some examples of conjugate heat transfer problems are:


- A heat sink that dissipates heat from a power supply unit by increasing the surface area in contact with the air flow generated by a fan. ²

- A shell-and-tube heat exchanger that transfers heat between two fluids separated by a thin metal wall. ²

- A nuclear reactor core that transfers heat from the fuel rods to the coolant fluid. ⁴

To solve conjugate heat transfer problems, one needs to use a numerical method that can handle both solid and fluid domains, as well as the coupling conditions at the interface. Some of the methods are:

- The domain decomposition method, which divides the problem into subdomains and solves them separately, then matches the solutions at the interface. ¹

- The finite element method, which discretizes the problem into elements and applies variational principles to obtain a system of equations. ²

- The finite volume method, which discretizes the problem into control volumes and applies conservation laws to obtain a system of equations. ³⁴

Below two parts of video tutorial of Conjugate Heat Transfer in Ansys Fluent (#12steps series)


Source: 

(1) Conjugate convective heat transfer - Wikipedia. https://en.wikipedia.org/wiki/Conjugate_Convective_Heat_Transfer.

(2) Conjugate Heat Transfer | COMSOL Blog. https://www.comsol.com/blogs/conjugate-heat-transfer/.

(3) Solving Conjugate Heat Transfer problems - Computational Fluid Dynamics. https://www.computationalfluiddynamics.com.au/conjugate-heat-transfer/.

(4) Conjugate Heat Transfer Simulation: Best Practices | SimScale. https://www.simscale.com/blog/cht-best-practices/.

Wednesday, August 23, 2023

Quick Tip: How to avoid Incorrect Wave Height in Ansys Fluent

According to my video and web search, this is a common issue that many Fluent users face when simulating open channel flow with wave boundary conditions . Some possible causes and solutions are:

You can find more details and examples on how to perform these steps in the following resources:

I hope this helps you avoid incorrect wave height in Ansys Fluent and achieve your desired simulation results. If you have any other questions, please feel free to ask me. 😊

Quick Tip: How to fix Error: GENERAL-CAR-CDR in Ansys (Fluent)

 The error message Error: GENERAL-CAR-CDR: invalid argument [1]: improper list means that there is a problem with the scheme code or the UDF (user-defined function) in your case or data file . Some possible solutions are:

  • Save the case and data file and try to reopen it.
  • Reset the Fluent Setup tab and try opening the mesh.
  • Remesh the geometry and reopen in Fluent.
  • Change the material definition from “Solid” to “Fluid” in Design Modeler.
  • Change the transient to steady if you are using evaporation-condensation as the phase interaction mechanism.
  • Check the syntax of your UDF and make sure it follows the new rules in Fluent 6.2.16 or later.

I hope this helps you resolve the error. If you need more assistance, please visit the Ansys Learning Forum or contact Ansys Support . Have a nice day! 😊

Sources:

1. smartadm.ru

2. cfd-online.com

3. forum.ansys.com

4. forum.ansys.com


In Polish 

Błąd: GENERAL-CAR-CDR oznacza, że wystąpił problem z kodem Scheme w programie Ansys Fluent. Scheme to język programowania używany do pisania funkcji zdefiniowanych przez użytkownika (UDF) lub makr w Fluent 1. Błąd ten pojawia się, gdy Fluent oczekuje listy wartości, ale otrzymuje inną wartość, np. fałszywą (#f) 2.

Możliwe przyczyny tego błędu to:

  • Niepoprawna skÅ‚adnia lub brakujÄ…ce znaki w kodzie Scheme
  • Niezgodność typów danych lub argumentów w funkcjach Scheme
  • NieprawidÅ‚owe ustawienia lub opcje w Fluent

Możliwe rozwiązania tego błędu to:

  • Sprawdzenie i poprawienie kodu Scheme, upewniajÄ…c siÄ™, że wszystkie nawiasy i cudzysÅ‚owy sÄ… zamkniÄ™te i dopasowane
  • Sprawdzenie i poprawienie typów danych i argumentów w funkcjach Scheme, upewniajÄ…c siÄ™, że sÄ… zgodne z dokumentacjÄ… Fluent
  • Zapisanie i ponowne otwarcie pliku przypadku i danych
  • Zresetowanie zakÅ‚adki ustawieÅ„ Fluent i ponowne otwarcie siatki
  • Przemieszanie geometrii i ponowne otwarcie w Fluent

Możesz znaleźć więcej informacji i przykładów na temat tego błędu na stronach internetowych 34. Mam nadzieję, że to ci pomoże. 😊

Tuesday, August 22, 2023

What are APDL commands in Ansys and what are they used for?

 APDL commands are text commands that you can use to perform various tasks in Ansys, such as defining material properties, applying boundary conditions, solving models, and post-processing results. APDL stands for Ansys Parametric Design Language, and it is a scripting language that allows you to automate and customize your Ansys workflows.

APDL commands can be entered in the Ansys Mechanical APDL interface, or in the command objects in Ansys Workbench. You can also write APDL scripts or macros that contain multiple commands and run them as a batch file. APDL commands can access the full functionality of Ansys, including features that are not available in the graphical user interface.

Some examples of APDL commands are:

  • MP,EX,1,200E9 - This command defines the Young’s modulus (EX) of material number 1 as 200 GPa.
  • L,1,2,3 - This command creates a line (L) from keypoint 1 to keypoint 2 to keypoint 3.
  • PLANE42 - This command selects the 4-node plane element type (PLANE42) for meshing.
  • SOLVE - This command initiates the solution process.
  • PRNSOL,U - This command prints the nodal solution data (U) for displacements.

If you want to learn more about APDL commands and how to use them in Ansys, you can check out the following resources:

Here are some more examples of APDL commands in Ansys that you might find useful:

  • /SOLU - Enters the solution processor, where you can apply loads and constraints, and solve the model.
  • D - Applies displacement constraints on selected nodes. For example, D,ALL,UX,0 applies a zero displacement in the X-direction on all nodes.
  • F - Applies force loads on selected nodes. For example, F,ALL,FZ,-100 applies a downward force of 100 N on all nodes in the Z-direction.
  • SF - Applies surface loads on selected elements. For example, SF,ALL,PRES,1E5 applies a pressure of 1E5 Pa on all elements.
  • SOLVE - Initiates the solution process and writes the results to the database.
  • /POST1 - Enters the general postprocessor, where you can review and manipulate the results of the solution.
  • PLNSOL - Plots a contour of a nodal or element solution item. For example, PLNSOL,U,SUM plots the total displacement of the nodes.
  • PRNSOL - Prints the nodal or element solution data to a file or the screen. For example, PRNSOL,S,X prints the stress in the X-direction of the elements.
  • /POST26 - Enters the time-history postprocessor, where you can review and manipulate the results of a transient or harmonic analysis.
  • PLTIME - Plots a graph of a variable versus time or frequency. For example, PLTIME,UZ,2 plots the displacement in the Z-direction of node 2 versus time or frequency.
  • PRNLD - Prints the load step data to a file or the screen. For example, PRNLD,FREQ prints the frequency values for each load step.

You can find more information and examples of APDL commands in Ansys in the following resources:

What is heat flux and what is its influence in numerical analyzes in CFD Ansys software

 Heat flux is a measure of the rate of heat transfer per unit area. It has the units of watts per square meter (W/m^2). There are three modes of heat transfer: conduction, convection, and radiation. Conduction is the transfer of heat within a solid or between solids in contact. Convection is the transfer of heat between a solid surface and a moving fluid. Radiation is the transfer of heat by electromagnetic waves, which can occur in a vacuum.

To perform a heat transfer analysis in Ansys, you need to use Ansys Mechanical, which is a finite element analysis software that can solve various types of problems, including thermal problems. You can use Ansys Mechanical to perform steady-state or transient heat transfer analyses, depending on whether the thermal loads are constant or vary over time. You can also apply different types of boundary conditions, such as temperature, heat flux, heat generation, convection, and radiation.

To learn more about heat transfer and how to use Ansys Mechanical for thermal analysis, you can check out the following resources:

  • Introduction to Heat Transfer: This is a PDF document that explains the basic concepts and equations of heat transfer, including Fourier’s law, convection coefficient, and Stefan-Boltzmann law.
  • How to Perform a Heat Transfer Analysis — Lesson 1: This is a video tutorial that shows you how to set up and run a steady-state thermal analysis in Ansys Mechanical using a simple example.
  • Ansys Mechanical Heat Transfer: This is a training course that covers the topics and features of Ansys Mechanical related to heat transfer analysis, such as thermal contact, thermal stress, thermal fatigue, and coupled-field analysis.

The influence of heat flux in numerical analyses in CFD Ansys programs depends on the type and mode of heat transfer that is being modeled. Heat flux is a measure of the rate of heat transfer per unit area, and it can affect the temperature distribution, fluid flow, and thermal stress in a system.

There are three modes of heat transfer: conduction, convection, and radiation. Conduction is the transfer of heat within a solid or between solids in contact. Convection is the transfer of heat between a solid surface and a moving fluid. Radiation is the transfer of heat by electromagnetic waves, which can occur in a vacuum.

In Ansys Fluent, you can model different types of heat transfer problems using various methods and boundary conditions. For example, you can use the following methods to model heat flux:

  • Surface heat flux: You can specify a constant or variable heat flux on a surface as a boundary condition. This can be used to model external heat sources or sinks, such as heaters, coolers, or solar radiation.
  • Heat generation: You can specify a volumetric heat source or sink within a solid or fluid domain as a source term. This can be used to model internal heat sources or sinks, such as chemical reactions, electrical currents, or nuclear fission.
  • Convection: You can specify a convective heat transfer coefficient and a reference temperature on a surface as a boundary condition. This can be used to model heat transfer between a solid surface and a fluid with known properties, such as air or water.
  • Radiation: You can use various radiation models to account for the effects of thermal radiation on the system. This can be used to model heat transfer between surfaces or between surfaces and the environment by electromagnetic waves.

The influence of heat flux on the numerical results depends on the magnitude, direction, and distribution of the heat flux, as well as the material properties, geometry, and boundary conditions of the system. For example, a higher heat flux can result in higher temperatures, faster fluid velocities, and larger thermal stresses in the system. A directional heat flux can create temperature gradients and induce natural convection in the system. A non-uniform heat flux can cause local hot spots or cold spots in the system.

To perform a reliable and accurate CFD analysis of heat transfer problems in Ansys Fluent, you need to choose an appropriate mesh size, time step, solver settings, convergence criteria, and validation methods. You also need to verify and validate your results with experimental data or analytical solutions.

If you want to learn more about how to use Ansys Fluent for CFD analysis of heat transfer problems, you can check out the following resources:

  • Ansys Fluent Theory Guide: This is a PDF document that explains the theoretical background and mathematical formulations of various models and methods used in Ansys Fluent.
  • Ansys Fluent User’s Guide: This is a PDF document that provides detailed instructions on how to use Ansys Fluent for various types of problems and applications.
  • Ansys Fluent Tutorials: These are video tutorials that demonstrate how to set up and solve different types of CFD problems using Ansys Fluent.

I hope this information was helpful for you. If you have any other questions or requests, please let me know. 😊

What are SMART and GPAD functionality in Ansys Mechanical and examples to use

Fatique analysis in Ansys Mechanical (with models description)

How to improve (reduce) skewness factor in Ansys Mechanical and CFD

Monday, August 21, 2023

What are SMART and GPAD functionality in Ansys Mechanical and examples to use

 I'm glad you are interested in using the SMART function in Ansys Mechanical. The SMART function is a feature that allows you to simulate the crack growth in engineering structures under fatigue or static loading conditions. SMART stands for **S**tress-intensity factor based **M**esh **A**daptive **R**e-meshing **T**echnique¹. 

Some examples of using the SMART function in Ansys Mechanical are:

- [A video tutorial](^1^) that demonstrates how to use the SMART function to simulate Mode I dominant fatigue or static crack growth in a pump housing. The video shows how to set up the initial crack geometry and mesh, the boundary conditions and loads, and the crack growth parameters and criteria. The video also shows how to view the results of the crack growth simulation, such as the stress intensity factors, the crack front shape, and the crack opening displacement.

- [A white paper](^2^) that explains the benefits and features of the SMART function, such as the Unstructured Mesh Method (UMM) that reduces the preprocessing time by using an automatically generated all-tetrahedral mesh for crack fronts. The white paper also provides some case studies of using the SMART function for different applications, such as a surface crack in a pressure vessel, a through-thickness crack in a pipe elbow, and a corner crack in a plate.

- [A lecture note](^3^) that introduces the basics of using Ansys Workbench and Ansys Mechanical for structural and thermal analyses. The lecture note covers topics such as the user interface, the geometry import and creation, the meshing process, the material properties, the boundary conditions and loads, the solution settings and controls, and the post-processing tools. The lecture note also includes some exercises and examples of using Ansys Mechanical for different types of analyses, such as static structural, modal, harmonic response, transient dynamic, thermal, and thermal-stress.

Source: 

(1) ANSYS Mechanical: Fatigue Crack Growth Analysis using SMART ... - YouTube. https://www.youtube.com/watch?v=8fy0hmTITEQ.

(2) ANSYS Mechanical: Fatigue Crack Growth Analysis using SMART ... - YouTube. https://www.youtube.com/watch?v=8fy0hmTITEQ.

(3) Ansys SMART Crack Growth & Fracture Modeling White Paper | Ansys. https://www.ansys.com/resource-center/white-paper/smart-fracture.

(4) Lecture 1 Introduction to ANSYS Workbench - Rice University. https://www.clear.rice.edu/mech517/WB16/lectures_trainee/Mechanical_Intro_16.0_L01_Intro.pdf.

Examples to use SMART function 

- [A video tutorial](^1^) that demonstrates how to use the SMART function to simulate Mode I dominant fatigue or static crack growth in a pump housing. The video shows how to set up the initial crack geometry and mesh, the boundary conditions and loads, and the crack growth parameters and criteria. The video also shows how to view the results of the crack growth simulation, such as the stress intensity factors, the crack front shape, and the crack opening displacement.

- [A white paper](^2^) that explains the benefits and features of the SMART function, such as the Unstructured Mesh Method (UMM) that reduces the preprocessing time by using an automatically generated all-tetrahedral mesh for crack fronts. The white paper also provides some case studies of using the SMART function for different applications, such as a surface crack in a pressure vessel, a through-thickness crack in a pipe elbow, and a corner crack in a plate.

- [A lecture note](^3^) that introduces the basics of using Ansys Workbench and Ansys Mechanical for structural and thermal analyses. The lecture note covers topics such as the user interface, the geometry import and creation, the meshing process, the material properties, the boundary conditions and loads, the solution settings and controls, and the post-processing tools. The lecture note also includes some exercises and examples of using Ansys Mechanical for different types of analyses, such as static structural, modal, harmonic response, transient dynamic, thermal, and thermal-stress.

I hope these examples help you to learn more about using the SMART function in Ansys Mechanical. If you have any questions or feedback, please let me know. 😊

Source:

(1) ANSYS Mechanical: Fatigue Crack Growth Analysis using SMART ... - YouTube. https://www.youtube.com/watch?v=8fy0hmTITEQ.

(2) ANSYS Mechanical: Fatigue Crack Growth Analysis using SMART ... - YouTube. https://www.youtube.com/watch?v=8fy0hmTITEQ.

(3) Ansys SMART Crack Growth & Fracture Modeling White Paper | Ansys. https://www.ansys.com/resource-center/white-paper/smart-fracture.

(4) Lecture 1 Introduction to ANSYS Workbench - Rice University. https://www.clear.rice.edu/mech517/WB16/lectures_trainee/Mechanical_Intro_16.0_L01_Intro.pdf.

GPAD function 

The GPAD function is a feature in Ansys Mechanical that allows you to perform adaptive meshing based on the geometry of the model. GPAD stands for **G**eometry-**P**reserving **A**daptive **D**iscretization³. The GPAD function enables you to start a simulation with a coarser mesh, and, as the model is solved, the solver monitors quantities like variation of stress in regions and automatically refines the mesh³. The mesh refinement is based on the underlying CAD geometry, not the initial coarse mesh. This means that the mesh refinement works closer to the true shape of the model².

The GPAD function can improve the accuracy and efficiency of structural mechanics simulations, especially in cases where the detailed geometry of the system plays a critical role in determining its physical behavior². For example, the GPAD function can be useful for simulating crack growth, extrusion, hyper-elasticity, and other nonlinear phenomena¹.

To use the GPAD function in Ansys Mechanical, you need to activate the Nonlinear Adaptive Region option in the Solution branch of the Outline tree. You can also specify the parameters for the adaptive meshing, such as the maximum number of remeshing cycles, the remeshing criterion, and the remeshing method¹.

You can find more information and examples about using the GPAD function in Ansys Mechanical in these videos¹⁴ and this white paper². I hope this answers your question. 😊


Source:

(1) Top 5 Features in Ansys Mechanical 2023 R1. https://www.ansys.com/blog/mechanical-2023-r1.

(2) Adaptive Meshing Preserves Geometry in Ansys Mechanical Release. https://simutechgroup.com/adaptive-meshing-preserves-geometry-in-ansys-mechanical-release/.

(3) How to Use Non-Linear Adaptive Meshing in Ansys Mechanical. https://www.youtube.com/watch?v=T90iGxHkmvQ.

(4)  https://go.edrmedeso.com/edrmedeso-tr.

(5)  https://www.linkedin.com/company/edr&.

(6) https://www.facebook.com/edrmedeso.

(7)https://twitter.com/EDRMedeso.

(8)  https://digitallabs.edrmedeso.com/new.

Some examples of using the GPAD function in Ansys Mechanical are:

- [A blog post](^1^) that lists the top 5 features in Ansys Mechanical 2023 R1, including the GPAD function. The blog post explains the benefits and features of the GPAD function, such as improved accuracy and efficiency, reduced preprocessing time, and automatic remeshing. The blog post also shows a screenshot of how to activate the GPAD function in the Solution branch of the Outline tree.

- [A video tutorial] that demonstrates how to use the GPAD function to simulate a crack growth problem in a pressure vessel. The video shows how to set up the initial crack geometry and mesh, the boundary conditions and loads, and the crack growth parameters and criteria. The video also shows how to view the results of the crack growth simulation, such as the stress intensity factors, the crack front shape, and the crack opening displacement.

- [A white paper](^2^) that explains the technical details of the GPAD function, such as the Unstructured Mesh Method (UMM) that reduces the preprocessing time by using an automatically generated all-tetrahedral mesh for crack fronts. The white paper also provides some case studies of using the GPAD function for different applications, such as a surface crack in a pressure vessel, a through-thickness crack in a pipe elbow, and a corner crack in a plate.

I hope these examples help you to learn more about using the GPAD function in Ansys Mechanical. If you have any questions or feedback, please let me know. 😊

Source: 

(3) Top 5 Features in Ansys Mechanical 2023 R1. https://www.ansys.com/blog/mechanical-2023-r1.

(4) Adaptive Meshing Preserves Geometry in Ansys Mechanical Release .... https://simutechgroup.com/adaptive-meshing-preserves-geometry-in-ansys-mechanical-release/.

Fatique analysis in Ansys Mechanical (with models description)

How to improve (reduce) skewness factor in Ansys Mechanical and CFD

What is Ansys Speos and how to use

Fatique analysis in Ansys Mechanical (with models description)

 ANSYS Mechanical is a software that can help you perform fatigue analysis on your models and predict the fatigue life and damage of your materials. ANSYS Mechanical offers various tools and features to help you set up, run, and post-process your fatigue analysis. For example:

I searched the web  and found some results that might be helpful. The first result is a course overview of ANSYS Mechanical Fatigue that covers the use of the Fatigue tool to perform stress-based and strain-based fatigue analysis in both the time and frequency domains. The second result is a video tutorial that explains how to perform fatigue analysis in ANSYS Workbench. The third result is another video tutorial that shows how to use the Fatigue tool in ANSYS Mechanical. The fourth result is a PDF document that provides an introduction to ANSYS fatigue analysis.

Below You can see the models of SN curve, EN curve and Morrow models. These are some of the models that are used to predict the fatigue life of a material based on the stress or strain cycles.

  • SN curve: This is a stress-life (S-N) curve that plots the stress amplitude versus the number of cycles to failure for a material. The SN curve is usually obtained from experimental tests under constant amplitude loading and fully reversed loading (R=-1), where R is the ratio of minimum to maximum stress. The SN curve can have different slopes depending on the stress level and the material behavior. For example, some materials may exhibit a fatigue limit, which is a stress level below which the material can endure an infinite number of cycles without failure. Other materials may not have a fatigue limit and show a continuous decrease in fatigue life with increasing stress. The SN curve can be used to estimate the fatigue life of a material when the stress is mostly elastic and the mean stress is low.
  • EN curve: This is a strain-life (E-N) curve that plots the strain amplitude versus the number of cycles to failure for a material. The EN curve is also obtained from experimental tests under constant amplitude loading and fully reversed loading (R=-1), but it considers both the elastic and plastic components of strain. The EN curve can be divided into three regions: low-cycle fatigue (LCF), high-cycle fatigue (HCF), and transition fatigue. In the LCF region, the plastic strain dominates and the material fails after a relatively small number of cycles. In the HCF region, the elastic strain dominates and the material fails after a relatively large number of cycles. In the transition region, both elastic and plastic strains are significant and the material exhibits an intermediate fatigue life. The EN curve can be used to estimate the fatigue life of a material when the strain is partly plastic and the mean stress is high.
  • Morrow model: This is a mean stress correction model that modifies the EN curve to account for the effect of mean stress on fatigue life. The mean stress is the average of the maximum and minimum stress in a cycle. The mean stress can influence the fatigue life of a material by changing the effective strain amplitude and causing either damage accumulation or damage recovery. The Morrow model assumes that only the plastic strain amplitude is affected by the mean stress, while the elastic strain amplitude remains constant. The Morrow model uses a modified endurance limit to calculate the corrected plastic strain amplitude based on the mean stress. The Morrow model can be used to improve the accuracy of fatigue life prediction when the mean stress is not zero.

I hope this description helps you understand more about these models. 😊

How to improve (reduce) skewness factor in Ansys Mechanical and CFD

What is Ansys Speos and how to use

What is Young Modulus in Ansys Mechanical (impact of this factor for structural analysis)

How to define porosity (porous medium) in Ansys CFD (Fluent, CFX)

How to improve (reduce) skewness factor in Ansys Mechanical and CFD

 Skewness is a measure of how much a cell deviates from an ideal shape. It is one of the most important indicators of mesh quality, as highly skewed cells can reduce the accuracy and stability of the numerical solution. Skewness is defined differently for different types of cells, such as triangles, tetrahedra, hexahedra, or polyhedra. In general, skewness is calculated as the difference between the shape of the cell and the shape of an equilateral cell of equivalent volume. The skewness value ranges from 0 to 1, where 0 means no skewness and 1 means maximum skewness. A good mesh should have low skewness values for most of the cells.

In ANSYS Mechanical and CFD, you can check the skewness of your mesh using various methods. For example, you can use the Report Quality button in the General task page to print a message to the console that shows the maximum cell skewness in your mesh. You can also use the Equivolume Skewness option in the Mesh Metric dropdown list in the Mesh Control task page to display a contour plot of the skewness on your mesh3. You can also use the Mesh Quality Criteria dialog box to set the minimum acceptable skewness value for your mesh and generate a report that shows how many cells violate this criterion.

There are different ways to improve your mesh quality and reduce the skewness in ANSYS. Here are some suggestions that you can try:

  • Modify your geometry to avoid sharp angles, small gaps, or thin features that can cause highly skewed cells. You can use the Geometry tool in ANSYS to edit your model and simplify it if possible.
  • Choose an appropriate element type for your mesh, such as tetrahedra, hexahedra, or polyhedra. Different element types have different skewness definitions and criteria. Generally, hexahedral elements have lower skewness than tetrahedral elements, but they are more difficult to generate for complex geometries. Polyhedral elements can adapt to any geometry and have lower skewness than tetrahedral elements, but they require more memory and computational time.
  • Adjust your element size to balance between accuracy and efficiency. A smaller element size can capture more details of the geometry and the physics, but it can also increase the number of cells and the skewness. A larger element size can reduce the number of cells and the skewness, but it can also lose some important information and introduce errors. You can use the Size Function option in ANSYS Meshing to control the element size based on various criteria, such as curvature, proximity, or sphere of influence.
  • Apply different meshing methods to different parts of your geometry, such as patch conforming, patch independent, or cutcell. Different meshing methods have different advantages and disadvantages in terms of quality, speed, and robustness. You can use the Method option in ANSYS Meshing to select the best meshing method for each part of your model.
  • Refine your mesh based on the change in cell volume or the gradient of cell volume. This can improve the smoothness of your mesh and reduce the skewness. You can use the Refinement option in ANSYS Meshing to refine your mesh based on various criteria, such as face size, face proximity, or face curvature.

You can check the skewness of your mesh using various methods in ANSYS Mechanical and CFD. For example:

There are other ways to improve the skewness factor besides the ones I mentioned in my previous response. Here are some additional suggestions that you can try:

I hope these suggestions help you further improve your skewness factor in ANSYS. 😊

If U want to read more interesting tips and tutorials try links below 

Cooling process of the gear on Transient Thermal (Ansys Workbench)

What is Ansys Speos and how to use

What is Young Modulus in Ansys Mechanical (impact of this factor for structural analysis)

How to define porosity (porous medium) in Ansys CFD (Fluent, CFX)

Sunday, August 20, 2023

Cooling process of the gear on Transient Thermal (Ansys Workbench)

 Transient Thermal module is a type of analysis that allows you to simulate the temperature changes and heat transfer in a system over time. It is useful for studying problems that involve time-dependent thermal loads, such as heat treatment, electronic cooling, engine heating, etc.

In Transient Thermal module, you need to specify the initial temperature distribution, the material properties (such as density, specific heat, and thermal conductivity), the boundary conditions (such as convection, radiation, and heat flux), and the time steps for the analysis. The module will solve the heat conduction equation for each time step and generate the results for the temperature, heat flux, heat transfer coefficient, etc.

You can also use Transient Thermal module to perform coupled thermal-structural analysis, where the thermal results are transferred to a structural analysis to calculate the thermal stresses and strains. This can help you evaluate the effects of thermal expansion, contraction, and deformation on your system.

If you want to learn more about Transient Thermal module in Ansys workbench, you can check out some of these resources:

- [Intro to Transient Thermal Analysis - ANSYS Innovation Courses](^5^): This is a PDF document that introduces the basics of transient thermal analysis and the governing equation.

- [Transient Thermal Analysis in ANSYS](^1^): This is a YouTube video that shows you how to do a transient thermal analysis in Ansys workbench with an example problem.

- [Transient heat transfer analysis using ANSYS workbench](^2^): This is another YouTube video that demonstrates how to perform transient heat transfer analysis using Ansys workbench with a different example problem.

I hope this helps you understand what is Transient Thermal module in Ansys workbench.

Source:

(1) Intro to Transient Thermal Analysis - ANSYS Innovation Courses. https://courses.ansys.com/wp-content/uploads/2020/05/Lesson-1-Introduction-to-transient-analysis.pdf.

(2) Transient Thermal Analysis in ANSYS - YouTube. https://www.youtube.com/watch?v=4Jj0s-DAvfg.

(3) Transient heat transfer analysis using ANSYS workbench. https://www.youtube.com/watch?v=wJW6IIovyPo.

(4) ANSYS Transient Thermal Tutorial - Convection of a Bar in Air. https://www.youtube.com/watch?v=fd0xQQ1IGvw.

(5) Setup Transient Thermal Analysis - ANSYS Innovation Courses. https://courses.ansys.com/index.php/courses/radiation-between-surfaces/lessons/physics-setup-lesson-5-16/topic/setup-transient-thermal-analysis/.

Friday, August 18, 2023

What is Ansys Speos and how to use

 ANSYS Speos is a software that can simulate and optimize the optical performance of systems, such as lighting, cameras, sensors, displays, etc. It can help you design and validate optical systems that meet your specifications and requirements. You can use ANSYS Speos when you want to:

  • Predict the illumination and optical behavior of your system in realistic conditions
  • Evaluate the impact of optical elements on human vision and perception
  • Optimize the optical design to improve efficiency, quality, and safety
  • Integrate optical simulation with other ANSYS products for multiphysics analysis
  • Reduce prototyping time and costs by using virtual testing and validation

Some of the features and capabilities of ANSYS Speos are:

I hope this gives you more information about ANSYS Speos and its features. If you want to learn more about how to use ANSYS Speos effectively, you can check out these sources: Ansys, Ansys Training, CADFEM.

To model in ANSYS Speos, you need to follow some general steps, such as:

  • Define the geometry of your optical system using ANSYS SpaceClaim or import it from another CAD software.
  • Define the optical properties of your materials, sources, and sensors using the Speos Optical Properties panel.
  • Define the simulation settings, such as the type of analysis, the wavelength range, the ray tracing options, etc., using the Speos Simulation panel.
  • Run the simulation and view the results using the Speos Results panel or the Speos Live Preview feature.
  • Post-process and analyze the results using various tools, such as sensors, probes, cameras, etc., or export them to other ANSYS products for multiphysics analysis.

These steps may vary depending on the specific application and complexity of your optical system. You can find more detailed instructions and examples on how to model in ANSYS Speos from these sources: Ansys Training, Ansys, Ansys Optics.

What is Young Modulus in Ansys Mechanical (impact of this factor for structural analysis)

 

Young’s modulus is a mechanical property that measures the stiffness of a solid material. It defines the relationship between stress (force per unit area) and strain (proportional deformation) in a material in the linear elasticity regime of a uniaxial deformation. Mathematically, this can be expressed as:


Young’s modulus is one of the input parameters when performing structural analysis in ANSYS Workbench. It affects the deformation and stress distribution of the material under external loads. A higher Young’s modulus means a stiffer material that resists deformation more. A lower Young’s modulus means a more flexible material that deforms more easily.

To perform structural analysis in ANSYS Workbench, you need to define the geometry, the material properties, the mesh, the boundary conditions, and the loads of your problem. Then, you need to solve the problem and post-process the results. You can use ANSYS Mechanical or ANSYS APDL to perform structural analysis12.

For more information on Young’s modulus and its impact on ANSYS Workbench, you can check out these sources: Ansys Learning Forum, Omnexus, Wikipedia.

The impact of Young’s modulus on the results in ANSYS Mechanical depends on the type of analysis and the material behavior. Young’s modulus is a measure of the stiffness of a material, which affects how much it deforms and stresses under external loads. Generally, a higher Young’s modulus means a lower deformation and a higher stress, while a lower Young’s modulus means a higher deformation and a lower stress.

For example, if you are performing a linear static analysis, which assumes that the material is elastic and the deformation is small, the Young’s modulus directly affects the displacement and stress results. The displacement is inversely proportional to the Young’s modulus, while the stress is directly proportional to the Young’s modulus. This means that if you increase the Young’s modulus of a material, you will get smaller displacements and larger stresses, and vice versa1.

However, if you are performing a nonlinear analysis, which accounts for large deformations, plasticity, or other nonlinear effects, the Young’s modulus is not the only factor that affects the results. You also need to consider other material properties, such as the yield strength, the hardening model, the Poisson’s ratio, etc. The Young’s modulus still affects the initial stiffness and elastic response of the material, but it may not be the dominant factor in determining the final deformation and stress results2.

Therefore, to understand the impact of Young’s modulus on the results in ANSYS Mechanical, you need to know the type of analysis you are performing, the material model you are using, and the boundary conditions and loads you are applying. You can also perform a parametric study or a sensitivity analysis to see how changing the Young’s modulus affects the results3. For more information on how to perform structural analysis in ANSYS Mechanical, you can check out these sources: Ansys Learning Forum, Ansys Blog, YouTube.

Interesting facts about Young Modulus 

Young’s modulus is a numerical constant that describes the elastic properties of a solid material when it is stretched or compressed in one direction. It is named after the 18th-century British scientist Thomas Young, who first proposed the concept of elasticity in 18071. However, the concept was developed earlier by Leonhard Euler in 1727, and the first experiments that used Young’s modulus in its current form were performed by Giordano Riccati in 1782.

Young’s modulus is a measure of the stiffness of a material, or how much it resists deformation under an applied force. A material with a high Young’s modulus is more rigid and less elastic than a material with a low Young’s modulus. For instance, steel has a Young’s modulus of about 200 GPa, which is about three times higher than that of aluminum. This means that steel is much harder to stretch or compress than aluminum.

Young’s modulus is only valid for small deformations that are reversible, meaning that the material returns to its original shape when the force is removed. This is called the elastic region of the material. If the force is increased beyond a certain point, the material will undergo permanent deformation, or plasticity. This is called the plastic region of the material. The point at which the material transitions from elastic to plastic behavior is called the yield point or yield strength of the material.

Young’s modulus is an important parameter in engineering and design, as it helps to determine how much a material can withstand stress without breaking or deforming. It also affects other properties of materials, such as thermal expansion, vibration, sound propagation, and elasticity of springs.

I hope this information was helpful and interesting for you. If you have any other questions or requests, please let me know. 😊

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