Friday, August 18, 2023

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. 😊

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

 To model porosity in ANSYS Fluent, you need to define the porous zone and the porous media properties in the setup. You can follow these steps:

  • In the Fluent interface, go to the Cell Zone Conditions panel and select the zone that you want to make porous. Check the Porous Zone option and click Edit.
  • In the Porous Zone panel, you can choose between two methods to specify the porous media resistance: the Superficial Velocity method or the Physical Velocity method. The Superficial Velocity method uses the superficial velocity (the velocity of the fluid if there were no porosity) to calculate the pressure drop across the porous zone. The Physical Velocity method uses the physical velocity (the velocity of the fluid inside the pores) to calculate the pressure drop across the porous zone. You can also choose between isotropic or anisotropic porosity, depending on whether the porosity is uniform or varies in different directions.
  • Depending on the method and the type of porosity you choose, you need to enter different parameters for the porous media. For example, if you choose the Superficial Velocity method and isotropic porosity, you need to enter the following parameters:
  • Click OK to apply your settings and close the panel.

You can also use user-defined functions (UDFs) to specify more complex or variable porous media properties. For more information on how to model porosity in ANSYS Fluent, you can check out these sources: YouTube, YouTube, YouTube, Ansys Learning Forum.

To model porosity in ANSYS CFX, you need to define the porous zone and the porous media properties in the setup. You can follow these steps:

  • In the CFX interface, go to the Cell Zone Conditions panel and select the zone that you want to make porous. Check the Porous Zone option and click Edit.
  • In the Porous Zone panel, you can choose between two methods to specify the porous media resistance: the Superficial Velocity method or the Physical Velocity method. The Superficial Velocity method uses the superficial velocity (the velocity of the fluid if there were no porosity) to calculate the pressure drop across the porous zone. The Physical Velocity method uses the physical velocity (the velocity of the fluid inside the pores) to calculate the pressure drop across the porous zone. You can also choose between isotropic or anisotropic porosity, depending on whether the porosity is uniform or varies in different directions.
  • Depending on the method and the type of porosity you choose, you need to enter different parameters for the porous media. For example, if you choose the Superficial Velocity method and isotropic porosity, you need to enter the following parameters:
  • Click OK to apply your settings and close the panel.

You can also use user-defined functions (UDFs) to specify more complex or variable porous media properties. For more information on how to model porosity in ANSYS CFX, you can check out these sources: YouTube, YouTube, YouTube, CFD Online.

If U want learn some other interested topics about Ansys, check links below:

How to define Joint in Ansys Static Structural and examples to use

Types of contacts on Ansys Static Structural and examples to use

How to model cracking phenomena in Ansys Mechanical (Structural)

How to define symmetry in Ansys Mechanical and CFD (CFX, Fluent)

Thursday, August 17, 2023

How to model cracking phenomena in Ansys Mechanical (Structural)

 Cracking phenomena are the processes of initiation, propagation, and failure of cracks in materials or structures due to various factors, such as stress, temperature, fatigue, corrosion, etc. Cracking phenomena can affect the performance, safety, and reliability of engineering systems and components. Therefore, it is important to be able to model and analyze cracking phenomena using simulation tools such as Ansys Mechanical.

Ansys Mechanical is a software product that provides finite element analysis (FEA) solutions for modeling structural mechanics problems. Ansys Mechanical can handle linear and nonlinear, static and dynamic, and thermal and coupled physics problems. Ansys Mechanical can also simulate various types of materials, such as metals, plastics, composites, and biomaterials.

To model cracking phenomena in Ansys Mechanical, you need to use some special features and capabilities that are available in the software. Some of these features are:

  • Fracture: This is a feature that allows you to define and apply fracture criteria to your model based on stress intensity factors (SIFs), energy release rates (ERRs), or J-integrals. Fracture can be used to simulate linear elastic fracture mechanics (LEFM) or nonlinear fracture mechanics (NLFM) problems. Fracture can also be used to model different types of cracks, such as pre-meshed cracks, arbitrary cracks, or semi-elliptical cracks.
  • SMART Crack Growth: This is a feature that allows you to simulate the growth and propagation of cracks in your model using separating morphing adaptive remeshing technology (SMART). SMART Crack Growth can handle 2D or 3D crack problems with complex geometries and loading conditions. SMART Crack Growth can also account for mixed-mode loading, contact effects, plasticity effects, and thermal effects.
  • XFEM: This is a feature that allows you to model cracks without explicitly meshing them using the extended finite element method (XFEM). XFEM can enrich the standard finite element approximation with additional functions that capture the discontinuity and singularity of the crack. XFEM can be used to model stationary or propagating cracks with various criteria, such as maximum hoop stress, maximum circumferential stress, or Paris law.

These are some of the features that you can use to model cracking phenomena in Ansys Mechanical. You can also use other features and tools that are integrated with Ansys Mechanical, such as Ansys Workbench, Ansys Fluent, Ansys APDL, etc., to create and manage your simulation projects.

If you want to learn more about how to use these features and tools to model cracking phenomena in Ansys Mechanical, you can check out some of the sources that I found using Bing:

  • Ansys Multiphysics Simulation for Crack Propagation Analysis: This is a webinar that demonstrates a multiphysics simulation for crack propagation analysis using Ansys Workbench, Ansys Mechanical, and Ansys Fluent. You will learn how to use SMART Crack Growth to analyze crack growth due to thermo-mechanical fatigue (TMF).
  • Get Cracking with ANSYS Workbench 19.2: This is an article that revisits Ansys Workbench to carry out a series of fracture mechanics analyses using SMART Crack Growth. You will learn how to create and edit joints in Ansys Workbench, how to specify the degrees of freedom, stiffness, damping, and friction properties for the joints, how to apply loads and moments to the joints, and how to post-process the results of the joint analysis.
  • how to create a crack on a 3D surface body in ANSYS workbench?: This is a forum thread that discusses how to create a crack on a 3D surface body in Ansys Workbench using Pre-Meshed Crack option. You will learn how to select the crack edge, top surface, bottom surface, and coordinate system for the crack definition.
If you are looking for some material models that can handle the cracking phenomena in Ansys Mechanical, you are in luck! I have found some amazing models that can do just that. Let me tell you more about them:

- **Anisotropic Plasticity using Hill Potential**: This model is perfect for metals that have different strengths in different directions, like a sheet of paper. It can show you how the metal gets damaged and breaks due to bending or stretching.
- **Cast Iron**: This model is great for cast iron materials, which are very strong when you squeeze them, but very weak when you pull them apart. It can show you how the cast iron cracks and shatters under tension, and how it depends on the temperature, the speed of loading, and the shape of the grains.
- **Microplane**: This model is awesome for concrete, which is a mixture of rocks, cement, and water. It can show you how the concrete cracks and softens when you pull it, and how it crushes and expands when you push it.
- **Shape Memory Alloys**: This model is amazing for shape memory alloys, which are metals that can change their shape when you heat them or stress them. It can show you how the shape memory alloys transform from one phase to another, and how they recover their original shape after being deformed.

These are some of the material models that can help you with your cracking phenomena in Ansys Mechanical. You can learn more about them by clicking on the links I have provided. I hope you find this interesting and helpful. 

The sources for the text are:

- [Understand a Design’s Breaking Point with Simple Crack Propagation Simulations](^1^): This is a blog post from Ansys that explains how to use the unstructured mesh method (UMM) and the separating morphing and adaptive remeshing technology (SMART) to simulate crack propagation in Ansys Mechanical. It also compares the results of UMM with the traditional hexahedral mesh method.
- [Material property data for engineering materials](^2^): This is a PDF document from Ansys that provides some material property data for common engineering materials, such as density, thermal conductivity, elastic modulus, etc. It also includes some physical constants, such as the gas constant, the Boltzmann constant, etc.
- [Simulate Brittle Cracking](^3^): This is a forum post from Ansys Learning Forum that discusses how to simulate the cracking of a nutshell in Ansys static structural. It also provides some screenshots of the model and the boundary conditions.

(1) Understand a Design’s Breaking Point with Simple Crack ... - Ansys. https://www.ansys.com/blog/breaking-point-crack-propagation-strength-of-materials.
(2) Material property data for engineering materials - Ansys. https://www.ansys.com/content/dam/amp/2021/august/webpage-requests/education-resources-dam-upload-batch-2/material-property-data-for-eng-materials-BOKENGEN21.pdf.
(3) Simulate Brittle Cracking - Ansys Learning Forum. https://forum.ansys.com/forums/topic/simulate-brittle-cracking/.

I hope this helps you understand how to model cracking phenomena in Ansys Mechanical. If you have any questions or feedback, please let me know. 😊



How to define symmetry in Ansys Mechanical and CFD (CFX, Fluent)

 Symmetry is a property of a system or a phenomenon that remains unchanged under certain transformations, such as reflection, rotation, or translation. Symmetry can be used to simplify the modeling and analysis of complex structures or problems by reducing the size and complexity of the model. Symmetry can also improve the accuracy and efficiency of the solution by eliminating unnecessary degrees of freedom and reducing numerical errors.


Ansys Mechanical is a software product that provides finite element analysis (FEA) solutions for modeling structural mechanics problems. Ansys Mechanical can handle linear and nonlinear, static and dynamic, and thermal and coupled physics problems. Ansys Mechanical can also simulate various types of materials, such as metals, plastics, composites, and biomaterials.

To model symmetry in Ansys Mechanical, you need to use some special features and capabilities that are available in the software. Some of these features are:

  • Symmetry Region: This is a feature that allows you to define and apply symmetry boundary conditions to your model based on the type and plane of symmetry. Symmetry Region can be used to model planar symmetry, cylindrical symmetry, spherical symmetry, or sector symmetry. Symmetry Region can also visually expand the results to show the full model for symmetric cases.
  • Slice: This is a feature that allows you to cut or split your model into smaller parts or slices based on a plane or a surface. Slice can be used to create symmetric parts or sectors from an original model. Slice can also preserve the material properties and mesh quality of the original model.
  • Coordinate System: This is a feature that allows you to create and align local coordinate systems based on the geometry or orientation of your model. Coordinate System can be used to define the direction and location of loads, supports, joints, or other features in your model. Coordinate System can also be used to specify the plane or axis of symmetry for your model.

Here are some examples of how to use these features to model symmetry in Ansys Mechanical for different types of problems:

  • Understanding When to Take Advantage of Symmetry Using Ansys Mechanical — Lesson 3: This is a video that shows how to use Symmetry Region to model planar symmetry and sector symmetry for a mechanical part with bolted connections. You will learn how to split bodies for symmetry in Ansys SpaceClaim, how to connect line bodies with solid bodies via Contact Region in Ansys Mechanical, how to create and align local Coordinate Systems based on geometry, how to define Bolt Pretension load in Ansys Mechanical, and how to visually expand symmetry results to show the full model.
  • How to setup Cyclic Symmetry model in ANSYS Workbench Mechanical: This is a video that shows how to use Slice and Coordinate System to model cylindrical symmetry for a turbine blade with centrifugal loading. You will learn how to slice a 3D body into a single-sector body in Ansys SpaceClaim, how to create a cylindrical coordinate system in Ansys Mechanical, how to apply rotational velocity and pressure loads in Ansys Mechanical, and how to post-process the results using cyclic expansion.
  • Understanding when to Take Advantage of Symmetry - Lesson 3: This is an article that revisits Ansys Workbench to carry out a series of fracture mechanics analyses using SMART Crack Growth. You will learn how to use Slice and Symmetry Region to model planar symmetry for a cracked plate with tensile loading. You will also learn how to apply fracture criteria based on stress intensity factors (SIFs) or energy release rates (ERRs) in Ansys Mechanical.

CFD Software 

Ansys Fluent and Ansys CFX are software products that provide computational fluid dynamics (CFD) solutions for modeling fluid flow and heat transfer phenomena. Ansys Fluent and Ansys CFX can handle various types of fluid flow problems, such as laminar or turbulent, compressible or incompressible, steady or transient, etc. Ansys Fluent and Ansys CFX can also simulate various types of fluids, such as gases, liquids, multiphase, reacting, etc.

To model symmetry in Ansys Fluent and Ansys CFX, you need to use some special features and capabilities that are available in the software. Some of these features are:

  • Symmetry Boundary Condition: This is a feature that allows you to define and apply symmetry boundary conditions to your model based on the type and plane of symmetry. Symmetry boundary condition can be used to model planar symmetry, cylindrical symmetry, spherical symmetry, or sector symmetry. Symmetry boundary condition can also visually expand the results to show the full model for symmetric cases.
  • Slice: This is a feature that allows you to cut or split your model into smaller parts or slices based on a plane or a surface. Slice can be used to create symmetric parts or sectors from an original model. Slice can also preserve the material properties and mesh quality of the original model.
  • Coordinate System: This is a feature that allows you to create and align local coordinate systems based on the geometry or orientation of your model. Coordinate System can be used to define the direction and location of loads, supports, boundaries, or other features in your model. Coordinate System can also be used to specify the plane or axis of symmetry for your model.

I see that you want to see some examples of how to use symmetry in Ansys CFX and Ansys Fluent. Symmetry is a property of a system or a phenomenon that remains unchanged under certain transformations, such as reflection, rotation, or translation. Symmetry can be used to simplify the modeling and analysis of complex fluid flow problems by reducing the size and complexity of the model. Symmetry can also improve the accuracy and efficiency of the solution by eliminating unnecessary degrees of freedom and reducing numerical errors.

Ansys CFX and Ansys Fluent are software products that provide computational fluid dynamics (CFD) solutions for modeling fluid flow and heat transfer phenomena. Ansys CFX and Ansys Fluent can handle various types of fluid flow problems, such as laminar or turbulent, compressible or incompressible, steady or transient, etc. Ansys CFX and Ansys Fluent can also simulate various types of fluids, such as gases, liquids, multiphase, reacting, etc.

To use symmetry in Ansys CFX and Ansys Fluent, you need to use some special features and capabilities that are available in the software. Some of these features are:

  • Symmetry Boundary Condition: This is a feature that allows you to define and apply symmetry boundary conditions to your model based on the type and plane of symmetry. Symmetry boundary condition can be used to model planar symmetry, cylindrical symmetry, spherical symmetry, or sector symmetry. Symmetry boundary condition can also visually expand the results to show the full model for symmetric cases.
  • Slice: This is a feature that allows you to cut or split your model into smaller parts or slices based on a plane or a surface. Slice can be used to create symmetric parts or sectors from an original model. Slice can also preserve the material properties and mesh quality of the original model.
  • Coordinate System: This is a feature that allows you to create and align local coordinate systems based on the geometry or orientation of your model. Coordinate System can be used to define the direction and location of loads, supports, boundaries, or other features in your model. Coordinate System can also be used to specify the plane or axis of symmetry for your model.

Here are some examples of how to use these features to model symmetry in Ansys CFX and Ansys Fluent for different types of problems:

  • Show Symmetry at CFD-POST (Results): This is a forum thread that shows how to use Symmetry Boundary Condition to model planar symmetry and sector symmetry for a half structure with an obstacle in the flow. You will learn how to set Symmetry (at Z axis) in Ansys Fluent, how to enable Beta Options in Workbench, and how to visually expand symmetry results in CFD-POST.
  • ANSYS Fluent Tutorial | Parametric Analysis In ANSYS Fluent | ANSYS Fluent Beginners Tutorial | CFD: This is a video that shows how to use Slice and Coordinate System to model planar symmetry for an airfoil with angle of attack variation. You will learn how to slice a 2D body into a half body in Ansys SpaceClaim, how to create a Cartesian coordinate system in Ansys Fluent, how to apply inlet velocity and outlet pressure boundary conditions in Ansys Fluent, and how to post-process the results using parametric analysis.

I hope these examples help you learn how to use symmetry in Ansys CFX, Fluent and Mechanical. If you have any questions or feedback, please let me know. 😊


How to define Joint in Ansys Static Structural and examples to use

  Joint boundary condition is a type of connection element that allows you to model the relative motion and interaction between two or more bodies in a structural analysis. Joint boundary condition can be used to simulate various types of joints, such as revolute, cylindrical, spherical, planar, slot, universal, and fixed joints. Joint boundary condition can also be used to apply loads and moments to the connected bodies.

To use joint boundary condition in Ansys Static Structural, you need to follow these steps:

  • In the Model tree, right-click Connections and select Insert > Joint.
  • In the Details view, select the type of joint you want to create from the drop-down list.
  • In the Geometry section, select the two or more bodies that you want to connect with the joint. You can also specify the location and orientation of the joint coordinate system (JCS) using the options available.
  • In the Definition section, specify the degrees of freedom (DOF) that you want to allow or restrict for the joint. You can also define stiffness, damping, and friction properties for the joint if needed.
  • In the Loads section, you can apply forces and moments to the joint in any direction. You can also define time-dependent or frequency-dependent loads using tables or functions.
  • Click Generate to create the joint boundary condition.

You can also modify or delete the joint boundary condition by right-clicking it in the Model tree and selecting Edit or Delete.

Here are some examples of how to use joint boundary condition in Ansys Static Structural for different types of joints:

  • Revolute Joint: This example shows how to model a revolute joint between a crank and a connecting rod of an engine. The revolute joint allows rotation about one axis and restricts all other DOF. A torque is applied to the crank and a force is applied to the connecting rod. The results show the stress distribution and displacement of the parts due to the joint motion.
  • Cylindrical Joint: This example shows how to model a cylindrical joint between a piston and a cylinder of an engine. The cylindrical joint allows translation and rotation along one axis and restricts all other DOF. A pressure load is applied to the piston and a fixed support is applied to the cylinder. The results show the stress distribution and displacement of the parts due to the joint motion.
  • Spherical Joint: This example shows how to model a spherical joint between a ball and a socket of a hip implant. The spherical joint allows rotation about three axes and restricts all other DOF. A force is applied to the ball and a fixed support is applied to the socket. The results show the stress distribution and displacement of the parts due to the joint motion.

I have searched the web for some relevant sources that show how to use joint boundary condition in Ansys Mechanical for different types of joints, such as revolute, cylindrical, spherical, planar, slot, universal, and fixed joints. You can watch some videos or read some articles that explain how to create and edit joints in Ansys Mechanical, how to specify the degrees of freedom, stiffness, damping, and friction properties for the joints, how to apply loads and moments to the joints, and how to post-process the results of the joint analysis. Here are some links that you can check out:

  • Working with Joints in ANSYS Mechanical | CAE Associates | ANSYS e-Learning: This video shows some of the tools and capabilities in Ansys Workbench v14.5 for defining and working with joints. It covers how to create joints using geometry scoping or remote points, how to modify or delete joints, how to use joint probes to plot joint forces and moments, and how to use joint loads to apply prescribed motion or displacement to joints.
  • ANSYS Explicit Dynamics: Using Joints, Joint Loads and Probes: This video shows how you can use joints in an Ansys Explicit Dynamics analysis to simulate the actual failure of an engine piston rod, which would not be possible with rigid bodies. It shows various joint types, joint loads, and joint probes that are available in Ansys Explicit Dynamics.
  • How to Model Joints via Constraints in Ansys Workbench Mechanical: This video shows how you can model joints via constraints in Ansys Workbench Mechanical using the command snippet feature. It explains how to use the MPC184 element type to create different types of joints, such as revolute, cylindrical, spherical, etc., and how to export the joint forces and moments using APDL commands.
  • Ansys Mechanical: All About Joints: This article covers some MAPDL commands to export joint element forces and moments as well as some strategies for working with joints in Ansys Mechanical. It explains why joints are useful for modeling complex mechanisms and interactions between bodies, and how to define and post-process joints using MAPDL.
  • Lecture 5 Modeling Connections: This lecture slides provide an overview of the different types of connections available in Ansys Mechanical, such as contact, bonded contact, bolted connection, spot welds, beam connection, etc. It also introduces the concept of joint boundary condition and shows some examples of using joints in Ansys Mechanical.

I hope these examples help you learn how to use joint boundary condition in Ansys Mechanical. If you have any questions or feedback, please let me know. 😊

If U want learn some other interested topics about Ansys, check links below:

Types of contacts on Ansys Static Structural and examples to use




Wednesday, August 16, 2023

Types of contacts on Ansys Static Structural and examples to use

Ansys Static Structural is a software that allows you to perform linear and nonlinear static analysis of structures, such as beams, plates, shells, and solids. One of the important aspects of static structural analysis is the contact between different parts of the structure, which can affect the stress, deformation, and load transfer.

According to the web search results, there are three main types of contacts in Ansys Static Structural: bonded, frictionless, and frictional¹². Each type of contact has different characteristics and applications, depending on the behavior of the interface between the parts.

- Bonded contact: This type of contact assumes that the parts are perfectly attached to each other, and there is no relative motion or separation between them. This means that both the normal and tangential forces are very large and resist any external forces that try to break or slide the parts. Bonded contact is useful for modeling welded joints, adhesive contacts, or some bolted connections¹².

- Frictionless contact: This type of contact allows the parts to separate from each other in the normal direction, but not to penetrate into each other. This means that the normal force is positive and prevents interpenetration, but zero when there is no contact. In the tangential direction, the parts can slide over each other freely, without any resistance. This means that the tangential force is zero. Frictionless contact is suitable for modeling well-lubricated interfaces or smooth surfaces¹².

- Frictional contact: This type of contact also allows the parts to separate from each other in the normal direction, but not to penetrate into each other. The normal force is similar to frictionless contact. However, in the tangential direction, the parts have some resistance to sliding over each other, depending on the coefficient of friction. This means that the tangential force is proportional to the normal force and the friction coefficient, until a maximum value is reached. Frictional contact is realistic for modeling most interfaces that have some roughness or dryness¹².

To use these types of contacts in Ansys Static Structural, you need to define them in the Contact branch of the Outline tree. You can either use the default contacts that are automatically generated by Ansys based on the geometry and proximity of the parts, or you can manually create your own contacts by selecting the contact and target surfaces. You can also modify the contact properties, such as stiffness, behavior, formulation, and friction coefficient in the Details view of each contact¹.

For some examples of how to use contacts in Ansys Static Structural, you can refer to these web pages:

- [Lecture 7 Static Structural Analysis](^1^): This lecture slides provide a comprehensive overview of static structural analysis in Ansys Mechanical, including how to define geometry, material properties, loads, supports, and contacts. It also includes two workshops on how to model a pump assembly with contact and a beam connection.

- [Introduction to Contact](^2^): This PDF document explains the basics of contact mechanics and how to model different types of contacts in Ansys Mechanical. It also includes some exercises on how to create and modify contacts for various scenarios.

- [Type of contacts in static structural](^3^): This forum post discusses how to choose between bonded and frictionless contacts for modeling an index finger that belongs to a hand orthosis model. 

Source: 

(1) Lecture 7 Static Structural Analysis - Rice University. https://www.clear.rice.edu/mech517/WB16/lectures_trainee/Mechanical_Intro_16.0_L07_Static.pdf.

(2) Introduction to Contact - ANSYS Innovation Courses. https://courses.ansys.com/wp-content/uploads/2019/05/2.5.1-Introduction-on-contact_New_Template_Master.pdf.

(3) Lecture 7 Static Structural Analysis - Rice University. https://www.clear.rice.edu/mech517/WB16/lectures_trainee/Mechanical_Intro_16.0_L07_Static.pdf.

(4) Introduction to Contact - ANSYS Innovation Courses. https://courses.ansys.com/wp-content/uploads/2019/05/2.5.1-Introduction-on-contact_New_Template_Master.pdf.

(5) Type of contacts in static structural - Ansys Learning Forum. https://forum.ansys.com/forums/topic/type-of-contacts-in-static-structural/.


No separation contact type 

No separation contact is a type of contact in Ansys Static Structural that assumes that the parts are initially in contact and remain in contact throughout the analysis. This means that there is no gap opening or closing between the parts, but sliding is allowed in the tangential direction. No separation contact is useful for modeling interfaces that have a very small clearance or interference, such as press-fit joints, shrink-fit joints, or snap-fit joints¹².

Some examples of how to use no separation contact in Ansys Static Structural are:

- [ANSYS Contact Types - Linear, Bonded & No-separation](^3^): This video tutorial shows how to create and modify different types of contacts in Ansys Workbench, including no separation contact. It also explains the difference between linear and nonlinear contacts, and how to check the contact status and results.

- [Contact Offset Control](^1^): This workshop demonstrates how to use the contact offset control feature to adjust the initial gap or penetration between parts with no separation contact. It also shows how to use the contact tool to view the contact information and results.

- [Using Joints](^1^): This workshop illustrates how to use joints to model connections between parts, such as springs, beams, and bushings. It also compares the results of using joints versus using no separation contact for a beam connection problem.

Source: 

(1) Ansys Contact Types and Explanations - Mechead.com. https://www.mechead.com/contact-types-and-behaviours-in-ansys/.

(2) Lecture 5 Modeling Connections - Rice University. https://www.clear.rice.edu/mech517/WB16/lectures_trainee/Mechanical_Intro_16.0_L05_Connections.pdf.

(3) ANSYS Contact Types - Linear, Bonded & No-separation - 38. https://www.youtube.com/watch?v=Z22sjU0PxFQ.

(4) Ansys Contact Types and Explanations - Mechead.com. https://www.mechead.com/contact-types-and-behaviours-in-ansys/.

(5) Ansys Contact Types and Explanations - Mechead.com. https://www.mechead.com/contact-types-and-behaviours-in-ansys/.

What is conjugate heat transfer and how to use in Ansys Fluent

What is, and when to use MRF method in Ansys Fluent

Rules for good quality mesh in Ansys Fluent

Tuesday, August 15, 2023

What is conjugate heat transfer and how to use in Ansys Fluent

Cnjugate heat transfer is a term that refers to the simulation of heat transfer between a fluid and a solid, or between two fluids separated by a solid wall. In Ansys software, conjugate heat transfer is usually achieved by coupling the fluid flow equations with the heat equation in both the fluid and the solid domains. This allows the software to account for the effects of convection, conduction, and radiation on the temperature distribution and heat flux in the system.

Conjugate heat transfer is important for many engineering applications that involve thermal processes, such as cooling systems, heat exchangers, combustion engines, electromobility, and more. By using Ansys software to model conjugate heat transfer, engineers can optimize the design and performance of these systems, as well as predict and prevent potential problems such as overheating, thermal stress, or thermal runaway.

Some examples of Ansys software that can handle conjugate heat transfer are [Ansys Fluent](^1^), [Ansys Mechanical](^2^), and [Ansys Twin Builder](^3^). These software packages have different features and capabilities for simulating conjugate heat transfer problems, such as meshing methods, physical models, boundary conditions, solver algorithms, and post-processing tools. You can learn more about these software packages by visiting their websites or reading some of their documentation and tutorials¹²³.

Source:

(1) Heat Exchanger Design Software | Ansys. https://www.ansys.com/applications/heat-exchangers.

(2) Ansys Fluent Heat Transfer Modeling | Ansys Training. https://www.ansys.com/training-center/course-catalog/fluids/ansys-fluent-heat-transfer-modeling.

(3) Intro to Heat Transfer Modeling in Ansys Fluent — Lesson 1. https://courses.ansys.com/index.php/courses/heat-transfer-modeling-in-ansys-fluent/lessons/introduction-to-heat-transfer-modeling-in-ansys-fluent-lesson-1/.

(4) Heat Exchanger Design Software | Ansys. https://www.ansys.com/applications/heat-exchangers.

(5) Ansys Fluent Heat Transfer Modeling | Ansys Training. https://www.ansys.com/training-center/course-catalog/fluids/ansys-fluent-heat-transfer-modeling.

(6) Intro to Heat Transfer Modeling in Ansys Fluent — Lesson 1. https://courses.ansys.com/index.php/courses/heat-transfer-modeling-in-ansys-fluent/lessons/introduction-to-heat-transfer-modeling-in-ansys-fluent-lesson-1/.

Example od Conjugate Heat Transfer on Ansys Fluent 

One example of conjugate heat transfer in Ansys Fluent is the simulation of a heat sink, which is a device that dissipates heat from a hot component (such as a CPU) to a cooler fluid (such as air). A heat sink typically consists of a solid base that is attached to the hot component, and a series of fins that extend from the base and increase the surface area for heat transfer. The fluid flows over the fins and carries away the heat from the solid.

To model this problem in Ansys Fluent, you need to follow these steps:

- Create the geometry of the heat sink and the fluid domain in Ansys DesignModeler or any other CAD software. You can use parameters to define the dimensions and properties of the heat sink and the fluid.

- Import the geometry into Ansys Meshing and generate a suitable mesh for both the solid and the fluid domains. You can use different meshing methods, such as sweep, hex-dominant, or tetrahedral, depending on the complexity and quality of the geometry. You can also use inflation layers to capture the boundary layer effects near the walls.

- Set up the physics and boundary conditions in Ansys Fluent. You need to enable energy equation and choose a suitable turbulence model for the fluid flow. You also need to specify the material properties and thermal conditions for both the solid and the fluid domains. For example, you can use a constant heat flux or temperature for the base of the heat sink, and a constant velocity or pressure for the inlet and outlet of the fluid domain. You can also use radiation models if you want to account for thermal radiation effects.

- Solve the problem and monitor the convergence. You can use different solver algorithms, such as coupled or segregated, depending on the stability and accuracy of the solution. You can also create report definitions and plots to monitor quantities of interest, such as temperature, heat transfer coefficient, Nusselt number, etc.

- Post-process the results and analyze them. You can use various tools in Ansys Fluent to visualize and quantify the results, such as contours, vectors, streamlines, iso-surfaces, etc. You can also export the results to other software, such as Ansys CFD-Post or Excel, for further processing.

If you want to see a detailed tutorial on how to perform this example in Ansys Fluent, you can watch this video¹ or read this document⁴. They will guide you through each step of the process and explain how to use different features and options in Ansys Fluent.

I hope this answer helps you understand what conjugate heat transfer is in Ansys Fluent and how to model it. If you have any more questions, feel free to ask me. Have a nice day! 😊

Source:

(1) ANSYS Fluent Student: Conjugate Heat Transfer - YouTube. https://www.youtube.com/watch?v=gEf48MworcA.

(2) Tutorial — Heat Transfer Modeling in Ansys Fluent — Lesson 6. https://courses.ansys.com/index.php/courses/heat-transfer-modeling-in-ansys-fluent/lessons/tutorial-heat-transfer-modeling-in-ansys-fluent-lesson-6/.

(3) ANSYS Fluent Student: Conjugate Heat Transfer in a Heat Sink. https://www.youtube.com/watch?v=OR1g6AsUJyI.

(4) ANSYS Fluent Tutorial | Conjugate Heat Transfer in a Rectangular Channel with Protrusions | Part 1/2. https://www.youtube.com/watch?v=5JoL_Qbxxq0.

If U want more interesting topics please see links below 

What is, and when to use MRF method in Ansys Fluent

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