Multibody Dynamics Updates in Ansys Motion 2020 R2 – Webinar

Ansys Motion, now in the Mechanical interface, is a third generation engineering solution based on an advanced multibody dynamics solver that enables fast and accurate analysis of rigid and flexible bodies and gives an accurate evaluation of physical events through the analysis of the mechanical system as a whole.

Ansys Motion uses four tightly integrated solving schemes (rigid body, flexible body, modal & meshfree EasyFlex) that give the user unparalleled capabilities to analyze in any combination imaginable. Large assemblies with millions of degrees of freedom can be studied with the effects of flexibility and contact included. With an integration into Mechanical, users can take advantage of multi-use models resulting in substantial time savings.

Join PADT’s Senior Staff Technologist, Jim Peters for an exploration of what this tool has to offer, and how seamlessly it integrates with the Ansys Mechanical interface.

Register Here

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Press Release: With New Capabilities in Metal 3D Printing, PADT Expands its Presence in the AM Value Chain

The world of Additive Manufacturing continues to evolve, and PADT’s offerings grow with those changes. Our latest advance is in the addition of a new system and an experienced engineer – an EOS M 290 and Keng Hsu, former ASU and Univeristy of Lousville professor. Read below to learn more.

We also have a PDF and HTML version of the release.

As always, if you have any questions, please contact us.


With New Capabilities in Metal 3D Printing, PADT Expands its Presence in the AM Value Chain

To Deepen its Investments in Metal Additive Manufacturing Research and Development, PADT Also Brought Onboard Veteran Engineer Keng Hsu as Principal AM R&D Engineer

TEMPE, Ariz., November 17, 2020 PADT, a globally recognized provider of numerical simulation, product development, and 3D printing products and services, today announced it has installed an advanced metal 3D printer from EOS, a global leader in the industrial metal 3D printing technologies, at its headquarters facility in Tempe, Arizona. With this increase in AM process and material capability, PADT can not only develop the highest quality end-use metal products, but also is well-positioned to address some of the current research and development challenges in additive manufacturing. PADT’s wide range of customers in highly demanding industries, most notably aerospace and defense, will see direct benefits of this new capability.

To lead metal additive manufacturing research and development (R&D), PADT also announced it has brought onboard Keng Hsu, engineer, researcher and associate professor at University of Louisville and formerly Arizona State University. Hsu brings more than 20 years of experience in equipment and facility operations, engineering R&D, engineering project execution and management in areas of advanced manufacturing of polymers, metals, and semiconductors. He has performed in-depth R&D contracts on 3D printing process and material development for some of the world’s largest technology organizations including Intel, Northrup Grumman, Salt River Project, the Department of Defense, and NASA.

“Metal 3D printing has reached a level of maturity that enables the production of end-use components and is now one of the fastest-growing manufacturing sectors in the world,” said Rey Chu, co-founder and principal, PADT. “The addition of the powerful EOS M290 printer to our portfolio expands the already extensive list of 3D printing capabilities and services we offer our customers. Our investments in technology and the addition of additive manufacturing veteran Keng Hsu also improves our ability to perform in-depth R&D on the potential of metal 3D printing.”

Dr. Keng Hsu

The EOS M 290 is a highly productive, and well-established mid-size AM system with a broad portfolio of metals for production of high-quality components, and for material and process R&D. PADT will initially run two of the machines most popular and versatile metals – stainless steel and nickel super alloy. The system also features a host of software tools, including its comprehensive monitoring suite, which enables quality assurance of all production- and quality-relevant data in real-time. Hsu will lead PADT’s R&D involved with the EOS machine and all other aspects of the company’s work in 3D printing R&D and consulting.

“The innovation made possible by metal 3D printing and in the technology itself is yet to be fully realized across many industries, namely aerospace,” said Hsu. “I’m grateful for the opportunity to join a leader in the industry and further my research on the subject to advance PADT’s presence in the field and services for our customers.”

PADT has been the Southwest’s premier additive manufacturing expert since it was founded in 1994 and continues to invest in innovative metal and polymer 3D printing systems, as well as talent, to better serve its customers. The company is ITAR registered and its quality system is also AS9100D (2016) and ISO9001:2015 certified to better serve the aerospace and defense industry. As an Ansys Elite Channel partner, PADT can also bring their extensive simulation experience to better design parts to take advantage of laser powder bed fusion and to optimize the build processes itself.

As 3D printing technology has advanced, PADT has seen an increase in the industry’s use of 3D scanning and printing for end-use parts. Metal 3D printing provides many benefits to aerospace and defense companies, including lighter, cheaper parts made much faster and with fewer constraints than with traditional manufacturing methods.

A full list of the EOS M 290’s specifications can be found on PADT’s website here . For more information on PADT and its capabilities in metal and plastic 3D printing, please visit www.padtinc.com.

About PADT

PADT is an engineering product and services company that focuses on helping customers who develop physical products by providing Numerical Simulation, Product Development, and 3D Printing solutions. PADT’s worldwide reputation for technical excellence and experienced staff is based on its proven record of building long-term win-win partnerships with vendors and customers. Since its establishment in 1994, companies have relied on PADT because “We Make Innovation Work.” With over 90 employees, PADT services customers from its headquarters at the Arizona State University Research Park in Tempe, Arizona, and from offices in Torrance, California, Littleton, Colorado, Albuquerque, New Mexico, Austin, Texas, and Murray, Utah, as well as through staff members located around the country. More information on PADT can be found at www.PADTINC.com.

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All Things Ansys 076: MAPDL – Elements, Contact & Solver Updates in Ansys 2020 R2

 

Published on: November 16th, 2020
With: Eric Miller & Ted Harris
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Simulation Support Manager Ted Harris for a discussion on what’s new in the Ansys Mechanical APDL 2020 R2 release.

If you would like to learn more about this update, you can view Ted’s webinar on the topic here:

https://www.brighttalk.com/webcast/15747/452033

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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Building a System Model of the RL-10 Rocket Engine in Flownex

When we engineers are building a new system or iterating on an existing design it can be expensive.  Simulating a full system-level model in a 3D CFD program can take days.  Making iterative changes to an existing system can be costly or even impossible. Utilizing a one-dimensional system modeler like Flownex allows us to analyze many different designs very quickly, on the order of seconds or minutes.

Flownex is a thermal-fluid network modeler.  It is a simulation tool that allows for 1D fluid modeling and 2D heat transfer.  It uses a variety of flow components, nodes, and heat transfer elements to model the entire system we are interested in analyzing.  It solves conservation of mass, momentum, and energy to obtain the mass flow, pressure, and temperature of fluids and solids throughout the complete network.  Because of this approach we can analyze large, complex networks very quickly, iterate on designs, and even run short or long transient simulations with ease.

In the example today we are looking at a version of the RL-10 rocket engine, which has been a staple in the delivery of satellites into orbit and an essential part of many spacecraft. The specific iteration of the RL-10 we will be using for building our network model is the RL10A-3-3A. A good place to begin with any system model is a system schematic:

Figure 2: RL10A-3-3A Engine System Schematic – Image from https://ntrs.nasa.gov/citations/19970010379

In Flownex we can assign an image (could be from a P&ID diagram, a CAD cross-section, or even a satellite image!) as the background for our drawing canvas. We simply need to right-click on the drawing canvas and select Edit Page to bring up the drawing canvas properties.

Clicking on the action button under Appearance Style brings up the Styles Editor.  Here we can change the fill style to Image and select the appropriate image for our background.

In the case of the RL-10 we can use the image from figure 2 as our background image.  We may want to consider adjusting the opacity of the image so that it blends into the background a little bit more.

In Flownex building a system model is as simple as drag and drop.  We can build our rocket engine using a variety of flow components from the Flow Solver library. To build the RL-10 system model we will be using the following components:

CEA Adiabatic Flame component to model combustion.

Composite Heat Transfer component to model thermal transport through pipe-walls to ambient and to model the regen.

Boundary Conditions to constrain our system at the inlets and outlet.

Basic Valves to model the different valves in the system,

Flow Resistances to model specified losses where appropriate.

Flow Interfaces to model the fluids entering the combustion chamber (to transfer fluid properties as we switch from two-phase O2 and H2 to gaseous fluids for modeling combustion.

Pipes for modeling various flow-paths.

Restrictors with Discharge Coefficient for our injection ports to the combustion chamber.

Restrictors with Loss Coefficient to model both the Calibrated Orifice and the Venturi contraction/expansion.

Basic Centrifugal Pumps for our Fuel and LOX pumps.

Simple Turbine to model the Fuel Turbine

Shafts to connect our different pumps mechanically.

Gearbox is used to connect the shafts between the LOX pump and the Fuel Pump.

Exit Thrust Nozzle to determine total thrust.

Script is used in assigning O2 properties prior to combustion.

The components may be dragged and dropped from the component library onto the drawing canvas to build our system model. We can also copy and paste components that are already on the canvas into different locations. This can be especially useful when the same inputs for say, a pipe, are used consistently throughout the model. All components have both Inputs and a Results associated with them as seen in the figure below. This is how we will define our flow components.

The completed model of the RL-10 Rocket Engine can be seen below. There are a few simplifications; we are using composite heat transfer components to model free convection to a specified ambient temperature (as though this was a land-based test). Rather than tie the actual temperatures and flow conditions in the nozzle to the regen we are using assumed temperatures and convective heat transfer coefficients. For additional fidelity we could model the heat transfer between these two flow paths with calculated convective heat transfer coefficients and we could model cross-conduction along the pipes which deliver the fuel and oxidizer to the combustion chamber. With additional effort, more complex use cases could also be simulated.

For the sake of demonstration we set up a transient action to slowly vary the oxidizer control valve fraction open; starting at 30% and ending at 100% open and observer the change in thrust at the nozzle as a function of this changing transient action.

Plots may be easily added by dragging a Line Graph from the Visualization > Graphs section of the component library onto our canvas. To choose the characteristics we would like plotted against time we simply need to drag and drop the desired inputs or results onto our newly placed line graph.

RL-10 Transient Thrust Plot

We can plot both the oxidizer control valve fraction open and the thrust versus time to observe the thrust reaction to the opening of the valve. The thrust plot has some jumps that are likely due to numerical singularities – with additional work this could be improved.

As can be seen, setting up complex system models in Flownex is relatively simple with most operations being drag and drop. For ease of sharing models with colleagues or customers adding a background image makes it very easy to see how the flow components in the model correspond with a system schematic. Setting up and plotting the effects of operational transients is a breeze!

For more information on Flownex please reach out to Dan Christensen at dan.christensen@padtinc.com.

MAPDL – Elements, Contact & Solver Updates in Ansys 2020 R2 – Webinar

The Ansys finite element solvers enable a breadth and depth of capabilities unmatched by anyone in the world of computer-aided simulation. Thermal, Structural, Acoustic, Piezoelectric, Electrostatic and Circuit Coupled Electromagnetics are just an example of what can be simulated. Regardless of the type of simulation, each model is represented by a powerful scripting language, the Ansys Parametric Design Language (APDL).

APDL is the foundation for all sophisticated features, many of which are not exposed in the Workbench Mechanical user interface. It also offers many conveniences such as parameterization, macros, branching and looping, and complex math operations. All these benefits are accessible within the Ansys Mechanical APDL user interface.

Join PADT’s Simulation Support Manager, Ted Harris for a look at what’s new for MAPDL in Ansys 2020 R2, regarding:

  • Contact Modeling & Robustness
  • Elements
  • Post Processing
  • Solver Components
  • And Much More

Register Here

If this is your first time registering for one of our Bright Talk webinars, simply click the link and fill out the attached form. We promise that the information you provide will only be shared with those promoting the event (PADT).

You will only have to do this once! For all future webinars, you can simply click the link, add the reminder to your calendar and you’re good to go!

All Things Ansys 075: Optical System Design & Disruption in Ansys SPEOS 2020 R2

 

Published on: November 2nd, 2020
With: Eric Miller & Robert McCathren
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Application Engineer Robert McCathren for a look at how Ansys 2020 R2 empowers SPEOS users to go further than ever before with enhancements that improve the handling of complex sensors, project preview and computation.

If you would like to learn more about this update, you can view Robert’s webinar on the topic here:

https://www.brighttalk.com/webcast/15747/449021

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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Introducing Level Up – An Ansys Mechanical Virtual Conference

PADT & Ansys are excited to announce Level Up with Ansys Mechanical, a free virtual technical conference on Wednesday, December 2, 2020 at 10 a.m. EST.

For the past 50 years, Ansys Mechanical continues to be the go-to finite element analysis platform for structural analysis, and they’re just getting warmed up. Join visionary Ansys product development, product management and engineering leaders as they provide expert insights on Mechanical’s technology advances and preview the platform’s future.

From those engineers looking to boot up their simulation experience to those seeking to step up their simulation skills, and even those operating in “beast mode”, who execute large and complex workflows, this action-packed event showcases how Mechanical radically transforms product design.

Highlights include: 

  • Learn the latest with scripting and automation to save valuable time
  • Discover how to lightweight product designs with structural optimization methods
  • Understand how to couple multiple physics to assess performance in the real world
  • And so much more

Catch the thought-provoking plenary presentation, engage with Ansys’ brightest during the live Q&A, and interact with fellow engineers during live polls. 

Register Here

Optical System Design & Disruption in Ansys SPEOS 2020 R2 – Webinar

When customers evaluate products, the overall look and details can make all the difference. Ansys physics-based imaging, photonics and illumination software streamlines the design process, so you can better understand how your product will look and operate under real-world lighting and usage conditions.

Whether you are designing a TV screen, street lighting network, smart headlight, head-up display or interior mood lighting in an automobile, Ansys optical simulation software helps you make your design more efficient and appealing. Optical sensors are the eyes of any intelligent system, and Ansys physics-based simulations can help you assess raw signals from camera and lidar systems in their operating environments.

Ansys 2020 R2 empowers Ansys SPEOS users to go further than ever before with enhancements that improve the handling of complex sensors, project preview and computation.

Enhancements include:

 •  Highly accurate camera models drastically improve camera simulation experience 

•  Faster simulation times when using light sources and provides nearly real-time review 

•  4X faster simulation setup thanks to optimized GUI

Join PADT’s Application Engineer Robert McCathren for a first hand look at the capabilities of optical simulation, followed by what’s available for SPEOS in the Ansys 2020 R2 update.

Register Here

If this is your first time registering for one of our Bright Talk webinars, simply click the link and fill out the attached form. We promise that the information you provide will only be shared with those promoting the event (PADT).

You will only have to do this once! For all future webinars, you can simply click the link, add the reminder to your calendar and you’re good to go!

Meshing in the New Ansys Fluent Task-based Workflows

Working with a variety of users with different levels of CFD (Computational Fluid Dynamics) backgrounds, I have to admit that Fluent meshing used to be a challenging and confusing task for beginners and even intermediate users.

Ansys has addressed this challenge by redesigning the Fluent user interface to provide a task-based workflow for meshing that enables engineers to do more and solve more complex problems than ever before in less time. The new Fluent task-based workflow streamlines the user experience by providing a single window that offers only relevant choices and options and prompts the user with best practices that deliver better simulation results.

Best practices are embedded into the workflow in the form of defaults and messages to the user. This reduces the amount of training required to start using the software and makes it easier for occasional users to return to the software.

How to Mesh Watertight CFD Geometry in the New Ansys Fluent Task-based Workflow

In order to use this workflow, you need a relatively clean watertight solid and/or fluid regions that can be meshed by surface meshing and then volume filling (no wrapping required.) Geometry can consist of single or multiple bodies.

Going through the task-based workflow is straightforward. You are presented with several steps, like:

  • Surface mesh.
  • Describe geometry. (Fluid and/or solid)
  • Capping. (If you are creating an internal flow volume, then the capping tools in Fluent makes extraction easy)
  • Volume meshing. (If you wish to use the latest Mosaic meshing technology, select “Poly-hexcore”)
Mosaic Meshing Technology

Now, click on “Switch-to-Solution,” to bring the mesh into a familiar Fluent interface.

Fault-Tolerant Workflow for Ansys Fluent Meshing Wraps and Seals Leaks and Gaps

Sometimes CFD simulations contain dirty, non-watertight geometries. For instance, 3D scanned or manufacturing geometry files. These geometries may contain missing faces, gaps, holes, overlaps, and other issues. As a result, they require extensive cleanup before simulation.

To overcome this obstacle, Ansys offers a new Fluent meshing workflow that wraps dirty geometry without cleanup.

The workflow for non-watertight geometry offers distinct advantages over other meshing technologies such as:

Part management:

Users can perform CAD-level changes to any geometry or assembly, including dragging and dropping objects from the CAD model into the simulation model.

Leakages and overlaps:

The fault-tolerant workflow seals leakages caused by gaps and misalignments between solid bodies. This significantly reduces the manual efforts required to clean up geometry.

The fault-tolerant workflow can easily wrap leaky geometry

STL file input

The workflow can create fluid regions directly from STL files or scanned data. This eliminates the need to convert STL files into solid geometry for the biomedical, oil and gas, automotive and other industries.

Imported STL File

2020R2 updates:

There are a few important improvements both in Watertight meshing (WTM) and Fault-Tolerant meshing (FTM) workflows in the 2020R2 release.

FTM/WTM: Wild card selection in lists

The Meshing Workflows now have an option to use a persistent Wildcard string for selecting labels or zones. This is in addition to the Filter Text option previously available. The new Use WildCard option stores the wildcard string itself in recorded workflows instead of an explicit list of locations so that when they are played back with new geometries, the matching will be performed again and pick up any matching zones/labels that were not in the earlier geometry.

WTM: Support of Region-specific Sizing 

You can specify region-specific Max Size and Growth Rates during the Volume Meshing task.  If you enable Region-based Sizing, Fluent will compute default sizing specifications for each region.  These can then be adjusted as required for each region.

WTM: Start From Imported Surface Mesh

This is useful if you have an established surface-meshing workflow or if you already have a mesh generated (perhaps from another preprocessor or an existing Fluent case) and want to use that as a starting point for Fluent meshing. Once you import the surface mesh you have the option of using it as it is, or selectively adding additional Local Size controls and/or remeshing particular surfaces as needed.

FTM: Continuous prism layers for Poly and Poly-Hexcore for Fluids

For the Fault-Tolerant Meshing Workflow you can now create continuous prism layers without stair-stepping within poly and poly-hexcore fluid regions.  Note that this will apply in all zones of the region.

WTM: Support of Local Sizing on Labeled Edges

Once you have labeled the edges, you can select Edge Size in Add Local Sizing to prescribe a target size on the selected edge(s).

All Things Ansys 074: Design & Digital Engineering Updates in Ansys 2020 R2

 

Published on: October 19th, 2020
With: Eric Miller & Robert McCathren
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Application Engineer Robert McCathren for a look at 3D product design and updates for Ansys Discovery AIM, Live, and SpaceClaim in 2020 R2.

If you would like to learn more about this update, you can view Robert’s webinar on the topic here:

https://www.brighttalk.com/webcast/15747/440598

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

Listen:
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@ANSYS #ANSYS

Press Release: PADT Expands its Operations in New Mexico With the Addition of 3D Printing Talent and Services

New 3D Printing Field Service Engineer Brings Exceptional 3D Printing Tooling and End-Part Production Skills and Knowledge to the Region

We are very pleased to announce that one of our 3D Printer experts is relocating to our New Mexico facility. Art Newcomer has moved to Albuquerque and will continue to support our Colorado and New Mexico cusotmers from there instead of our Littleton Office.

Read more in the press release below or as a PDF or HTML.

As always, if you have any questions, please contact us.


PADT Expands its Operations in New Mexico With the Addition of 3D Printing Talent and Services

New 3D Printing Field Service Engineer Brings Exceptional 3D Printing Tooling and End-Part Production Skills and Knowledge to the Region

TEMPE, Ariz., October XX, 2020 PADT, the Southwest’s leading provider of numerical simulation, product development, and 3D printing products and services, today announced 3D printing expert Art Newcomer is relocating from the company’s Colorado office to its long-standing New Mexico facility, located in Sandia Science & Technology Park (SS&TP). The move comes on the heels of PADT’s expanded capabilities and services in 3D printing and numerical simulation in California and Texas. Combined, these recent moves bolster the company’s ability to serve the growing region.

“Art has done a fantastic job supporting our Colorado customers and has been a significant contributor to our growth in the state,” said Ward Rand, co-founder and principal, PADT. “As a member of the PADT support team, he will continue to serve Colorado customers. Art’s move to New Mexico simply expands his impact on a region that has seen a significant acceleration of 3D printing adoption, making his extensive knowledge and talents a real asset there moving forward.”

Newcomer has been serving PADT’s 3D printing customers for five years, and has nearly 20 years of experience as a field service engineer across different technologies and sectors. In his role at PADT, he applied his talents to help customers install, maintain, and repair their Stratasys additive manufacturing systems across a wide variety of industries including aerospace, defense, medical, and industrial.

PADT’s growing customer base in New Mexico has expanded the application of proven Stratasys 3D printing technologies to include more tooling and end-part production. The National Labs in New Mexico were pioneers in the application of 3D Printing and PADT has been proud to work with them over the years as they increase their efforts and find new applications for the technology.

“I’m looking forward to taking on a new challenge in New Mexico where PADT has served for many years,” said Newcomer. “The growth of 3D printing investments in the region provides us with a great opportunity to use our hard-earned expertise to educate customers on how to best implement the technology and to keep their systems operating at peak performance”

To learn more about PADT’s services in New Mexico as well as its continued expansion throughout the Southwest, please visit www.padtinc.com.

About PADT

PADT is an engineering product and services company that focuses on helping customers who develop physical products by providing Numerical Simulation, Product Development, and 3D Printing solutions. PADT’s worldwide reputation for technical excellence and experienced staff is based on its proven record of building long-term win-win partnerships with vendors and customers. Since its establishment in 1994, companies have relied on PADT because “We Make Innovation Work.” With over 90 employees, PADT services customers from its headquarters at the Arizona State University Research Park in Tempe, Arizona, and from offices in Torrance, California, Littleton, Colorado, Albuquerque, New Mexico, Austin, Texas, and Murray, Utah, as well as through staff members located around the country. More information on PADT can be found at www.PADTINC.com.

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Design & Digital Engineering Updates in Ansys 2020 R2 – Webinar

The Ansys Discovery suite of tools allows engineers to improve their 3D design capabilities, by increasing productivity, improving product quality, and spurring innovation. Explore ideas, iterate and innovate with unprecedented speed early in your design process with Ansys 3D design software.

Delve deeper into design details, refine concepts and perform multiple physics simulations to better account for real-world behaviors. 

Join PADT’s Application Engineer Robert McCathren for a look at 3D product design and updates for Ansys Discovery AIM, Live, and SpaceClaim in 2020 R2.

In the Ansys 2020 R2, users can explore large design spaces and answer critical design questions early in the product design process without waiting days or weeks for traditional simulation results.

Additionally, these tools have been upgraded to support concept modeling and model prep for importing modified CAD geometry, auto-skinning topology optimization results from Ansys Mechanical for automated geometry reconstruction, and so much more.

Register Here

If this is your first time registering for one of our Bright Talk webinars, simply click the link and fill out the attached form. We promise that the information you provide will only be shared with those promoting the event (PADT).

You will only have to do this once! For all future webinars, you can simply click the link, add the reminder to your calendar and you’re good to go!

All Things Ansys 073: LS-DYNA Updates in Ansys 2020 R2

 

Published on: October 5th, 2020
With: Eric Miller & Jim Peters
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Senior Staff Technologist Jim Peters to discuss the capabilities of the explicit simulation tool LS-DYNA, and look into what’s new in the 2020 R2 version of the latest Ansys acquisition.

If you would like to learn more about this update, you can view Jim’s webinar on the topic here: https://www.brighttalk.com/webcast/15747/440598

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

Listen:
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Efficient and Accurate Simulation of Antenna Arrays in Ansys HFSS – Part 2

Finite Arrays

In addition to explicit modeling of finite arrays in Ansys HFSS, there are three other methods based on using unit cells. To learn more about the unit cell, please see part 1 of this blog.

In part 2, I will introduce and compare these 3 methods (1) Finite array defined using the array setting in unit cell, (2) Finite Array using Domain Decomposition Method (FADDM), (3) 3D component arrays (Figure 1). Please note that that the method 3 requires HFSS 2020R1 or newer.

(a)

(b)

(c)

Figure 1. (a) Unit cell, (b) FADDM, (c) 3D component array.

Finite Array using Unit Cell

After defining a unit cell (Figure 1a), you may simply define the number of elements, the spacing between them, and the scan angle. The assumption is that there is no mutual coupling, every element has the same radiation pattern and the same excitation. This is a good approximation for large arrays (10×10 or larger). This method may not be accurate enough in some cases, for example for a small number of elements; and when the antenna elements have main beams toward the angles that are close to the plane of the array and toward the other elements, causing a higher level of mutual coupling. However, smaller arrays won’t require as large of a compute resource as a large array.

The advantage of this method is its simulation speed. It requires the minimum memory and time to provide a quick array simulation. To define the array (after running the analysis for unit cell), right-click on Radiation from the Project Manager window. Select Antenna Array Setup, and then Regular Array Setup. In the Antenna Array Setup under Regular Array type, define the location of the first cell, the direction, the distance between the cells and number of cells in each direction.

(a)  

(b)

(c)

Figure 2. Steps to define a finite array, (a) Antenna array setup, (b) & (c) Regular array setup.

Finite Array using Domain Decomposition Method

General Domain Decomposition (DDM) for a single domain provides a way to reduce memory requirement, however, it does not reduce the meshing time for large explicit arrays. Using Finite Array DDM (FADDM) addresses this shortcoming. The FADDM bypasses the adaptive meshing stage by duplicating the mesh that was generated for a unit cell. While the unit cell is used to create the mesh, the assumption of uniform excitation is no longer present. Each element in FADDM can have different magnitude and phase and is individually modeled, however, the mesh created in the unit cell is used to generate the overall mesh, therefore, no CPU time is spent on generating the mesh. This can be seen in Figure 3, by linking the mesh of the unit cell to the FADDM, the mesh is copied, and no mesh refinement will be needed. You may compare it with the explicit array of the same size (Figure 3(c)) where the entire array has to be meshed and mesh refinement will be necessary for adaptive meshing. This can be a huge simulation time saving when the array size is large.

(a)

(b)

(c)

Figure 3. (a) Mesh from a unit cell, (b) mesh linked to FADDM, (c) explicit array mesh.

To create FADDM from unit cell, create a new HFSS design. Then copy the unit cell into the new design. In the Project Manager window, right-click on Model and choose Create Array, as shown in Figure 4. This opens the window that allows user to define the number of elements of the array along the lattice directions. By selecting “Active Cells” tab, user can define where active, passive and padding cells are located. This gives the user a means of creating different lattice shapes.

Please note that padding cells defined in the General tab represent the size of vacuum buffer surrounding the array. They are not visible to the users but are included in the FADDM simulation. The same mesh from the unit cell simulation is duplicated to padding cells (Figure 5). It is also possible to add padding cells in the Active Cells tab, and those cells are also invisible, but can be used to create the array lattice of the desired shape (Figure 6).

Figure 4. The steps to create a DDM array, the Padding Cells are used to create the vacuum box and are invisible to the user.

Figure 5. The FADDM needs a padding cell to create a vacuum box around the design. The padding cells are invisible to the user.

(a)

(b)

Figure 6. (a) Padding cells can be used to create a lattice, (b) the lattice created does not show the padding cells.

The next step is to link the mesh to the unit cell. First, an analysis setup should be created. Choose Advanced Solution Setup. In the Driven Solution Setup General tab, reduce the number of Maximum Number of Passes to 1, as shown in Figure 7(a), then choose Advanced tab and click on Import Mesh (Figure 7(b)). Click on Setup Link. This is to link the simulation to the mesh of a unit cell. There are two steps needed here. First, choose the file or design that contains the mesh information (Figure 7(c)), second is to map the variables Figure 7(d). The last step to setting up the analysis is selecting Advanced Mesh Operation tab and selecting “Ignore mesh operation in target design” (Figure 7(d)). Now the array is ready and simulation can be run. You notice that adaptive meshing goes to only one pass. If in Setup Link window the option of “Simulate source design as needed” is checked (Figure 7(c)), then if a design variable that affects the geometry is changed, the meshing of the unit cell is repeated as needed. After the simulation is completed the elements magnitude and phases can be changed as a post processing step by “Edit Sources” (right-click on Excitations). The source names provided in the edit sources is slightly different than an explicit array (Figure 8)

(a)

(b)

(c)

(d)

(e)

Figure 7. Different windows related to setting up a linked mesh in FADDM.

Figure 8. Edit sources gives the ability to change the magnitude and phase of each element.

To compare the run-time and array patterns an example of circular polarized microstrip patch antenna of a 5 ´ 5 element array is shown in Figure 9 and Figure 10. The differences can be seen at angles away from the broadside angle. This shows how the edge effects are ignored in the unit cell approximation. Table 1 shows the comparison of memory and runtime for the three methods.

Table 1. Comparing run time and memory needed for a 5 x 5 array, explicit array vs FADDM.

Elapsed Time (min:sec) Memory (MB)
Unit cell01:0683.1
FADDM03:1781.4
Explicit Array25:0694.7

Figure 9. Comparison of the far-field patterns for LHCP (co-polarization) created using FADDM and unit cell array.

Figure 10. Comparison of the far-field patterns for RHCP (cross-polarization) created using FADDM and unit cell array.

Finally, we compare the co-polarization pattern with an explicit 5 x 5 element array for scan angles of 0 and 30 degrees in  Figure 11 and Figure 12, respectively.

Figure 11. Comparison of far-field LHCP created by explicit array vs. FADDM.

Figure 12. Comparison of scanned far-field LHCP, scan angle of 30 degrees.

3D Component Array

In 2020R1 the option of 3D component array was added. This option provides a means of combining different unit cells in one array. The unit cells are defined and imported as 3D components. To create a 3D component unit cell, define each type of the cells in a separate HFSS design, run the analysis, then select all objects in the model. In the Model ribbon, click on Create 3D Component, assign a name (no spaces are allowed in the name), add any information you like to add such as owner, email, company, etc., then click OK. Once all the 3D component cells are created, create a new HFSS design for the 3D component FADDM.

The next step is to create Relative CS for each of the 3D component elements in the HFSS design that will contain the array. For this step you need to plan the array lattice ahead of time, so the components are placed in the proper locations (Figure 13). Overlap is not allowed.

The unit cells should have the followings:

  • Identical dimensions of the bounding boxes
  • Identical Primary/Secondary (Master/Slave) boundary on the unit cells.

The generation of FADDM is similar to single unit cell array, except that when you select Model->Create Array, the window will be shown as 3D Component Array Properties (Figure 14). After choosing the number of elements and the number of padding cells, the unit cells window (Figure 15) will give you options of choosing one of the 3D component unit cells for each location of the elements in the lattice. The cells can be color coded. In the example shown in Figure 16  there are 3 components, the blank cell, the vertical cell and the horizontal cell. The sources under Edit Sources window are also arranged based on the name of the 3D component cells. At this point there is no option of linking the mesh. Therefore, the number of passes for adaptive mesh should be set to a number that is appropriate for getting a convergence.

Figure 13. 3D component unit cells are arranged to create a 3D component array.

Figure 14. The 3D component array can be created the same way as creating FADDM using a unit cell.

Figure 15. The unit cells are color coded for easier lattice creation.

Figure 16. The result of lattice created using 3D component array.

Conclusion

Unit cell and Finite Array Domain Decomposition are excellent options for simulating large finite arrays within a reasonable runtime and memory requirements. The 3D component finite array is a nice added feature in 2020R1 that now provides a way to combine unit cells with different geometries in one array.

If you would like more information related to this topic or have any questions, please reach out to us at info@padtinc.com.

All Things Ansys 072: Building Digital Twins in Ansys 2020 R2

 

Published on: September 21st, 2020
With: Eric Miller, Matt Sutton & Josh Stout
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Senior Analyst & Lead Software Developer Matt Sutton, and Systems Application & Support Engineer Josh Stout for a discussion on the advantages of using Ansys Twin Builder to create simulation-based virtual replicas of physical assets for testing, as well as what’s new and improved for this tool in the 2020 R2 release.

If you would like to learn more about this update, you can view Matt’s webinar on the topic here: https://www.brighttalk.com/webcast/15747/437059

If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at podcast@padtinc.com we would love to hear from you!

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