The State of Mechanical Meshing in Ansys 2021 R1 – Webinar

Meshing is an integral part of the engineering simulation process where complex geometries are divided into simple elements that can be used as discrete local approximations of the larger domain. The mesh influences the accuracy, convergence and speed of the simulation. Furthermore, since meshing typically consumes a significant portion of the time it takes to get simulation results, the better and more automated the meshing tools, the faster and more accurate the solution.

Ansys provides general purpose, high-performance, automated, intelligent meshing software which produces the most appropriate mesh for accurate, efficient multiphysics solutions — from easy, automatic meshing to highly crafted mesh. 

Join PADT’s Senior Mechanical Engineer and meshing expert Joe Woodward for an introduction to the new meshing capabilities available in Ansys 2021 R1, including updates for: 

• Repairing Topology

• Weld Control

• Separating Morphing Adaptive Remeshing Technology (SMART)

• Batch Connections

• 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).

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Travel Trailer Analysis in ANSYS Discovery

ANSYS Discovery is a wonderful tool for fast and first look structural, fluid flow, and thermal simulations. Discovery gives us the ability to modify geometry very quickly within the interface and to add or remove features to view realtime simulation reactions. This allows us to quickly iterate, explore design changes, and better understand interaction between our design and the environment. Today we are going to be investigating the pressure profile on the exterior of a travel trailer being pulled behind a truck down the highway.

Truck and Trailer with velocity streamlines

In this analysis we are using a 2018 Chevy Silverado 2500 model pulled from GrabCAD with a generic 25 foot travel trailer. Based on described experience we’ve noticed that the roof and sidewalls of a moderately sized travel trailer seem to bow outwards at highway speeds near the front of the trailer.

The first thing to do is to put this model in an enclosure and prescribe a flow condition at the inlet and a pressure boundary at the outlet. Modeling the truck/trailer combo at a speed of ~55 mph (25 m/s) confirms that there is suction (negative pressure) present in these key areas:

Negative Pressure: Truck and Trailer in 25 m/s airflow, -500 Pa isosurface

While the actual roof and sidewall separating could be attributed to poor manufacturing processes we wonder if there could be a design change to minimize negative pressure/suction. One idea would be to incorporate some sort of turbulator to break up the laminar flow. I’ve seen turbulator tape in a zig-zag pattern used in aviation for this specific purpose so we’ll try recreating the travel trailer equivalent and see how it goes.

I started with a zig-zag pattern about 4″ tall on top of the trailer to see if I could “pop the bubble”

This did have the intended consequence and it was curious to see how much impact the turbulator on top of the trailer had on the negative pressure at the sidewall of the trailer:

The next thing I wanted to try was moving the turbulator forward or backward to see the effects. Moving the turbulator towards the aft of the vehicle has limited effects but moving it to different locations within the suction “bubble” seems to effect our -500 Pascal isosurface:

This would seem to indicate the presence of a “sweet spot” for turbulator location that merits further research in either the “Analyze” mode within Ansys Discovery or within Ansys Fluent.

Before I hang up my coat I’d like to investigate one alternate design that I’ve seen more often in automotive applications. I’m going to try adding vertical pillars and see how that goes:

We can easily change the height and position of the pillars to see the resultant effects on the pressure isosurface. The pillars also have a significant effect on the suction bubble but I notice that it has less effect on the suction on the sides of the trailer.

Using Discovery we can quickly and easily iterate on designs, get a first-view of the physics, and determine which change or design merits further investigation. In this analysis we can see that there is most definitely a suction profile at the front of a generic travel trailer. If the suction proves damaging we can see that there are several design changes which will help to mitigate this effect.

For more information on ANSYS Discovery please reach out to info@padtinc.com.

If you would like to play with the models themselves, you can download a zip file with all three models here.

All Things Ansys 082: High Frequency Updates on Ansys 2021 R1

 

Published on: February 26th, 2021
With: Eric Miller & Aleksandr Gafarov
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Electronics Application Engineer Aleksandr Gafarov for a look at what’s new in this electromagnetics release.

When it comes to high frequency electromagnetics, Ansys 2021 R1 delivers a plethora of groundbreaking enhancements. Ansys HFSS Mesh Fusion enables simulation of large, never before possible electromagnetic systems with efficiency and scalability.

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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@ANSYS #ANSYS

Alternating Stresses in Ansys Mechanical – Part 2: von Mises Stress

Editor’s Note:
The following PowerPoint is from one of PADT’s inhouse experts on linear dynamics, Alex Grishin.

One of the most valuable results that can come from a harmonic response analysis is the predicted alternating stresses in the part. This feeds fatigue and other downstream calculations as well as predicting maximum possible values. Because of the math involved, calculating derived stresses, like Principal Stresses and von Mises Stress can be done in several ways. This post shows how Ansys Mechanical does it and offers an alternative that is considered more accurate for some cases for von Mises. Part 1 covers how to do the same for Principal Stresses.

Alternating_vonMises_Stress

Alex also made this zip file that contains updated macros, an example Mechanical database, and a spreadsheet:

General Interface & Performance Updates in Ansys 2021 R1 – Webinar

Ansys 2021 R1 delivers significant improvements in simulation technology together with nearly unlimited computing power to help engineers across all industries reimagine product design and achieve product development goals that were previously thought to be impossible.

Ansys Mechanical delivers features to enable faster simulations, easier workflows, journaling, scripting and product integrations that offer more solver capabilities. Within this new release, interface and performance capabilities have been enhanced to offer greater ease of use and overall efficiency in nearly every circumstance. 

Join PADT’s Simulation Support Manager and Ansys expert Ted Harris, for an overview of what updates in this release best energize this tool, such as enhancements made to:

• Solution History

• Fluid Network Creation

• Circuits

• GPU & Solvers

• 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!

A PADT Engineer in King Attiball’s Court – Chapter 1

There just is not enough engineer-focused fiction out there. Romance, Horror, Sci-Fi, Young Adult, Historical, Mystery, etc. They all do well, but they are rarely written for the engineers of the world.

Here at PADT, we are all about undoing such injustices. We decided to brainstorm a story about an engineer who does simulation and 3D Printing and ends up on an adventure. We hope they will find some mystery, some science fiction, and some horror. Maybe even a little romance. To develop the characters and the plot we all got on an MS Teams meeting and blocked it out. It was a lot of fun. That turned into an outline, that will turn into a chapter every month.

We hope you enjoy the result as much as we enjoyed dreaming the journey up.

It should be noted that every character in this story is completely made up. Sometimes we steal some names from real people as a shoutout to them, but that is about it. PADT does not have a basement or a fancy cluster in one. Everything is made up. Well, almost everything. We do have a stack of furniture in the back of shipping and receiving.



Chapter 1
Batch Submission

Everyone’s work cubical is different. Some develop a zone of chaos. Some use it as a place to display the things they care about. Some, like Ash, keep theirs stark and clean.  She found it difficult to focus if one item was out of place or if her monitor was not at the perfect height and angle. She started and finished each day with the same ritual. A ritual that guaranteed that at least this little corner of her world was controlled, clean, and understood.

Most days, it worked. But no matter how hard Ash tried, she was going to end up in a place that she could not control, keep clean, or even understand. If she knew that facilities would soon start using her cubicle to store large, blue water bottles, she would have thrown a fit. At this point, she had no idea how unusual things would soon become. But, we are getting ahead of our story.

On this particular day, she walked into her cubicle with an extra bounce in her step. She straightened the diploma on the wall that said, “Asghleith Jones, PhD, Computation Fluid Mechanics.”  She even made sure her tape, stapler, pen holder, stack of sticky pads, and metal straight-edge were in their proper position. She realized that the only picture in her office, a group photo of the Phoenix Phoenicians LARP’ers, had been moved by the cleaning crew again. With a gentle nudge, she put it back into its proper position.

Ash was on the taller side with a fit figure that she usually kept hidden under baggy khakis and a polo shirt.  She had bright, intelligent green eyes, dark olive skin, and a mass of black, curly hair.  Hair she almost always kept tied back behind her head and down her back. After turning 27 the previous month, she had recommitted to her regimen of running and yoga that kept her feeling healthy and energetic.

The large backpack she placed on the floor next to her desk, and the bounce in her step were related. After work, she was heading to a campground outside of Tucson, Arizona, to meet up with the group in the picture. They were going to spend a whole week pretending to be a group of Ancient Phoenician traders. Live-action role-playing, LARPing, was her passion.  A passion she could not wait to indulge. She just needed to get this huge fluid flow simulation set-up and solving on the server before leaving. Then she could relax and slide into her alter-ego.

“Hey, Ash, ready to go a’LARPing?”  She looked up from her monitor to see Harriet Rumanicci, PADT’s HR manager and her best friend at work, standing in the door.

“Don’t make fun of me,” she answered.  “It is relaxing and good therapy. No computers, no meetings, no nosy co-workers, and best of all, no deadlines.” 

Harriet came in and sat on the guest chair in the cubicle. Petit, blond, and full of energy, she was the only person keeping the various employees at PADT socially connected. She also truly enjoyed teasing Asghleith.  

She continued that teasing with, “How can someone who is a neat freak like you spend a week living in the desert? Do you sweep your tent every hour?”

Ash stopped typing and looked directly at Harriet with the most severe look she could muster. “As the manager of HR, you should know that my OCD is a disability, and making fun of me is discriminatory.”

“I don’t know. In your line of work, it may be an asset.”

They both laughed. 

Harriet slightly adjusted the position of Ash’s stapler and then asked, “Are you going to be able to submit the big job before you take off?”

“Yes,” said Ash, adding a sigh. “If I am not interrupted and if they get the server back up and running today.”

“Oh, you need the help of IT?”

“I do, and they are being very nice and responsive. Because they like engineers. But, the new hard drives may not be here in time. I’ve got an email into someone named -” Ash stopped speaking to click on her computer screen. “ – Alex Adalopopolopolus in the government projects team, to see if I can run on their cluster.  I heard it was massive with lots of new, super-duper-magic-fast hardware.”

“I know Alex. But then that is my job.” Harriet smiled at her little joke. “He seems a good guy, doesn’t talk much. In fact, he never leaves the basement.”

“Well, he will be this project’s lifesaver if he can get me a login and peel off some nodes with dual GPU’s, 128 gigabytes of memory, and four terabyte RAM drives for me to solve on.”

“I heard, lifesaver, blah, blah, dual goats, blah, blah, solve on,” joked Harriet.

“Exactly.”

Harriet sat comfortably in Ash’s cubical, checking and responding to emails as Ash continued to type and click at her computer.  They often worked like this, not saying much, just sharing the same space and tossing the occasional comment back and forth. The silence, and their productivity, was broken when Oren Barnett’s well-coifed head popped up over Ash’s cubical wall.

“Hey, Ash. How is that big run coming? Is it done yet? I got a big order that should drop as soon as you give them results.” 

Harriet said, “Oren. Bringer of anxiety. Can’t you see the lady is busy?”

Oren raised himself a bit higher so he could see where the unexpected voice was coming from. “Oh, I see HR is here. Isn’t making fun of me against some sort of corporate policy?”

“Let me check.” Harriet pretended to scroll through her phone. After a few seconds, she said, “No.”

Ash chuckled as she continued to work. She then said, “I should have it submitted this afternoon. A few more hours to get the boundary layer on these critical surfaces, then I’ll re-mesh one last time to get everything in its place.  The new drives won’t make it in today, so Alex in IT just gave me a week on the government cluster in the basement.”

Oren climbed up on the chair that he kept on his side of the cubical wall, resting his arms on top of the divider.  “Perfect, thank you, Ash.  It’s an important project that could lead to a seven-figures worth of HPC if we, well you, can show them how they can fix their problem.”  He paused to look at Harriet and considered if he should continue or not. 

He decided to continue.

“Ash, once you get that job submitted, can I take you to dinner as a reward?”

Harriet’s face darted up from her phone to glare at Oren.  Asghleith tried to ignore the proposition by typing faster and harder on her keyboard.

“Come on. You have worked hard all week.  All month, really.  Let me pay you back the best way I know how.” He smiled at her. “Time with me.”

Ash felt a bit trapped.  The truth was, as annoying as he could be, Oren made her laugh, and even though he put pressure on her all the time, he was always supportive and did everything he could to help her get her job done. And she could not deny, his smile was charming.  On the other hand, Harriet didn’t like him at all. She was also continually sharing stories of past office romances that had ended disastrously, often with HR involved. 

As much as she felt tempted to give in to Oren’s constant attempts to get her to go out with him, she had a valid excuse this time. 

“Sorry, guy. I’m leaving town for the week right after work.”

Oren’s smile faded. “Oh. Darn.  Going someplace fun?”

Ash continued typing and said, almost to herself, “I certainly hope so.”

At around four-thirty, the model was ready.  While Ash copied it to her thumb drive, she straightened her office up.  Everything was moved into the proper drawer or put in its perfect place. She smiled a bit when she realized that Harriett had moved her stapler and then put it where it belonged. 

Moments later, she was headed down the stairs to the basement.  Most people didn’t know that PADT even had a basement. The entrance was back behind a pile of old furniture stacked in the rear of shipping and receiving. 

At the bottom of the stairs, she pushed a simple red button with a small sign under it that said: “Push Me, All who Wish to Enter.”

A voice said, “You must be Asg-ha-leeth Jones?”

“Yes, No. Ash-Lee or Ash. Parents thought it was a sophisticated way to spell my name.” A flood of memories came back of her explaining to people since kindergarten that her name was Ashley.   

“Anyway,” she continued, “that is me. Do you need some ID or something?”

“No, you are good. Please enter.”

The door buzzed and slid open.  Ash stepped through into a small room with glass walls.  All around, on the other side of the glass walls, were rows and rows of computers.

“So cool,” she said to herself.

The same voice from the door said, “It is, isn’t it. Literally and figuratively. We keep the room at sixty-two degrees.  And it is a lot of very fast computers. Some with some pretty cool new technology. Which, I cannot tell you about.”

Startled, Ash asked, “Umm, who is this?”

The voice calmly answered, “I am the AI that lives on this computer. Although, we could debate if I actually live or exist.”

This was a shock to Ash. She thought the computer was used to run really large simulations for the government, she had no idea it could host an AI algorithm that sounded so human.

“Just kidding.” Said the voice in the ceiling. “This is Alex Adalopopolopopulus. You can just call me Alex A.” He paused. “Alex-ah. I am just kidding, again. Alex is fine. It is a pleasure to talk to you in person instead of through email.”

“Likewise.  Thank you so much for getting me time on this machine. I feel like a kid in a candy store. And I do like the idea of calling you Alex-ah.  Might as well, since you are a disembodied voice.”  She looked around for a terminal to sit at and realized there was no desk, no keyboard.  A large monitor was hanging from the back wall, next to the door where she had entered. 

“Welcome to the Phoenix Cluster, our state of the art hybrid quantum-digital compute cluster.  It integrates eight-thousand-one-hundred and ninety-two cores with six quantum compute nodes.  It also has a state of the art passive augmented reality interface.”

All Ash could say was, “so cool.”

“Indeed, my young padawan. Let’s get you loaded and started. There is a USB port under the monitor. Go ahead and put your thumb drive in.  Then stand on the yellow pad in the corner.”

Ash shifted her large backpack on her shoulders and walked to the monitor, more than a little nervous. She slid the thumb drive in. She then took a few steps to stand on a yellow circle in the corner by the monitor. 

As soon as she had both feet on the pad, her skin felt tingly. The room around her and the computers on the other side of the windows all faded, and she saw a cartoon version of the room.  A mouse, keyboard, and monitor floated in front of her.  She reached out and touched the keyboard. As her fingers made virtual contact, she felt something pushing back against them.

Before she could say it herself, she heard Alex’s voice in her ear, “I know, so cool!”

“I am kind of speechless. This is so awesome. As much as I want to play with this interface, I gotta get on the road, so here goes.”

Ash started to type on the keyboard and saw her command form on the monitor.

Ash–> cfdsolve1 -s fluent -t 2022-03-12-23:00 bc -loads-c1.txt -c Phoenicia -jn t75-c1-a

The command Asghleith typed in was supposed to start a batch script that ran Ansys FLUENT starting at eleven that night on the Phoenix cluster. As she pressed the virtual enter key, she realized that she put the dash on the boundary condition flag, bc, in the wrong place and had typed Phoenicia instead of Phoenix.

She thought it would be no big deal. The script would error out, and she would type it in correctly. Instead, she felt a jolt as if she was in an old elevator that had started to move up. On the screen, she saw the words, “Batch Job Submitted.  Engaging Quantum Temporal Solver.”

She struggled to stand as the whole room began to jump and shake. Her head began to spin.  The keyboard and monitor faded in front of her, replaced by blindingly bright light. She closed her eyes, but that did not help. The spinning got worse.

As she began to lose consciousness, she said, “Alex-A, I think I entered the wrong command.”  

-To Be Continued –

Please enjoy the next chapter, “New Friends.”

When we next join Ash she will encounter a mob, a wise man of science, ducks, and of course, a princess.

And don’t forget to subscribe to our newsletter, so you know when the next installment is released.

To be continued

High Frequency Updates in Ansys 2021 R1 – Webinar

Whether leveraging improved workflows or leading-edge capabilities with Ansys 2021 R1, teams are tackling design challenges head on, eliminating the need to make costly workflow tradeoffs, developing next-generation innovations with increased speed and significantly enhancing productivity, all in order to deliver high-quality products to market faster than ever.

When it comes to high frequency electromagnetics, Ansys 2021 R1 delivers a plethora of groundbreaking enhancements. Ansys HFSS Mesh Fusion enables simulation of large, never before possible electromagnetic systems with efficiency and scalability. This release also allows for encrypted 3D components supported in HFSS 3D Layout for PCBs, IC packages and IC designs to enable suppliers to share detailed 3D component designs for creating highly accurate simulations.

Join PADT’s Lead Electromagnetics Engineer and high frequency expert Michael Griesi for a presentation on updates made to the Ansys HF suite in the 2021 R1 release, including advancements for:

  • Electronics Desktop
  • HFSS
  • Circuits
  • EMIT
  • 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!

Press Release: Ansys Elite Channel Partner and Stratasys Diamond Channel Partner, PADT Announces Jim Sanford as Vice President of Sales & Support

The Sales and Support team at PADT is the group that most of PADT’s customers interface with. They sell world-leading products from Ansys, Stratasys, and Flownex and then provide award-winning support long after the initial purpose. The team has grown over the years and has plans for even more growth. To help make that happen, we are honored to have Jim Sanford join the PADT family as the Vice President of our Sales & Support team.

Many of our customers and partners know Jim from his time with industry leaders Siemens, MSC, Dassault Systems, and NextLabs, Inc. He brings that experience and his background as a mechanical engineer before he entered sales, to focus PADT on our next phase of growth. He also fit well in PADT’s culture of customer focused, technical driven sales and support.

Our customers have a choice of who they purchase their Ansys multiphysics simulation, Stratasys 3D Printers, and Flownex system simulation software from, and who delivers their frontline support. We know with Jim leading the team, even more companies will make the choice to be part of the PADT family.

The official press release has more details, and can be found at these links or in the test below.

Press Release: PDF | HTML

Want to have a conversation about your Simulation or 3D Printing situation? Contact PADT now and one of our profesionals will be happy to help.


Ansys Elite Channel Partner and Stratasys Diamond Channel Partner, PADT Announces Jim Sanford as Vice President of Sales & Support

Sanford Brings a Wide Range of High-Profile Leadership Experience Across Technology and Aerospace and Defense Sectors to his New Position

TEMPE, Ariz., February 11, 2021 PADT, a globally recognized provider of numerical simulation, product development, and 3D printing products and services, today announced the addition of Jim Sanford as vice president of the company’s Sales & Support department. In his new position, Sanford is responsible for leading the increase of sales and customer support for a range of best-in-class simulation and additive manufacturing solutions. Sanford reports to Ward Rand, co-founder and principal, PADT.

“In the last few years, PADT has expanded across the Southwest, adding new expertise and technologies to our product and service offerings,” said Rand. “Jim is a valuable addition to the team and will be instrumental in sustaining PADT’s growth across the region. His leadership, experience, and knowledge of the industry will allow us to increase the pace of expansion and bring our solutions to serve new and existing customers in deeper and more impactful ways to their businesses.”

After a comprehensive search, Sanford proved to be the most experienced and capable leader to take on the vice president role. He will focus on providing visionary guidance, strategy, and tactical direction to the department. His responsibilities include refining the company’s sales team structure, recruiting, hiring, training, managing for profitable growth, and leading the support team to ensure an optimal customer experience for their use of Ansys, Stratasys, and Flownex products.

Prior to joining PADT, Sanford held business development and engineering positions in a diverse range of aerospace and defense, modeling and simulation, and software companies. His 30-year career span includes executive leadership roles at Siemens, MSC, and Dassault. Most recently he served as the VP for NextLabs Inc., a leading provider of policy-driven information risk management software for large enterprises, and the VP of Business Development for Long Range Services, where he was engaged in the development and testing of various classified items for the U.S. Department of Defense. He holds a bachelor’s degree in Mechanical Engineering from the University of Arizona, with emphasis in materials science and physics.

“PADT is a well-respected brand well-known for its product knowledge, customer-centric approach, and expertise,” said Sanford. “My career has been defined by my ability to take technology-focused companies to the next level of success, and I’m thrilled to join PADT and help continue its expansion by supporting highly innovative customers.”

PADT currently sells and supports the entire Ansys product line in Arizona, California, Colorado, Nevada, New Mexico, Texas, and Utah as an Ansys Elite Channel Partner. They also represent all Stratasys products in Arizona, Colorado, New Mexico, Texas, and Utah as a Diamond Channel Partner and are the North American distributor for Flownex.

To learn more about Sanford and PADT’s products and services, please visit https://www.padtinc.com/products/

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.

# # #

All Things Ansys 081: Meshing & UI updates in Ansys Fluent 2021 R1

 

Published on: February 8th, 2021
With: Eric Miller & Sina Ghods
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Senior Simulation Support & Application Engineer and fluids expert Sina Ghods for a look at what’s new in this release.

For fluids simulation in this release, products can be designed faster than ever before, thanks to major physics and productivity enhancements that build upon the tool’s ​already powerful workflow and meshing capabilities.

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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@ANSYS #ANSYS

Workflow & Meshing Updates in Ansys Fluent 2021 R1 – Webinar

From small to mid-sized companies to global organizations, companies of every size seek new ways for pioneering breakthrough innovations that are safer and more reliable to win the race to market.

Ansys 2021 R1 delivers significant improvements in simulation technology together with nearly unlimited computing power to help engineers across all industries reimagine product design and achieve product development goals that were previously thought impossible.

For fluids simulation in this release, products can be designed faster than ever before, thanks to major physics and productivity enhancements that build upon the tool’s ​already powerful workflow and meshing capabilities. Join PADT’s Senior Simulation Support & Application Engineer and fluids expert Sina Ghods for a look at what’s new in this release including: 

• Fluent User Interface Updates

      • Meshing Workflow Advancements

      • Combustion Applications

      • Turbomachinery Applications

      • Battery Modeling Applications

      • Multiphase and DPM Improvements

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 080: 2020 Wrap-up & Predictions for Ansys in the New Year

 

Published on: January 25th, 2021
With: Eric Miller & PADT’s Ansys Support Team
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by the simulation support team to look back at the past year of Ansys technology and make some predictions regarding what may happen in the year to come.

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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@ANSYS #ANSYS

Phoenix Children's Hospital 3D printed heart model. (Image courtesy Phoenix Children's Hospital)

Workflow for Creating a 3D Printed Medical Model with Stratasys

For decades in the medical world, surgeons and their professional support teams have relied on X-rays, computed tomography (CT) scans and magnetic resonant imaging (MRI) data when performing their pre-surgical planning approach. These diagnostic tools have been literal lifesavers, yet the resolution and 2D perspective of these images can make it difficult to determine the full details of anatomical geometry. Subtle, critical abnormalities or hidden geometries can go unnoticed when viewing flat films and digital displays.

3D printed heart model produced by Phoenix Children’s Hospital. (Image courtesy Phoenix Children’s Hospital)

With the advent of 3D printing, many surgeons are now using 3D models for both surgical planning and patient communication. While cost is the primary hold-back, such models are seeing increased use. In addition, efforts are underway to quantify the benefits of reduced operating room time/expense and improved patient outcome; see Medical 3D Printing Registry (ACR/RSNA). Supporting this concept are the high-resolution, multi-material PolyJet 3D printers from Stratasys.

But how does the patient’s CT and MRI data become a unique 3D printed model you can hold in your hand? How do you segment out the areas of interest for a particular analysis or surgical model? This blog post describes the necessary steps in the workflow, who typically performs them, and the challenges being addressed to improve the process every step of the way.

Data Acquisition of Patient Anatomy

When we think of imaging throughout the decades, X-ray technology comes to mind. However, classic single 2D images on film cannot be used to drive 3D models because they are qualitative not quantitative. The main options that do work include the series of x-rays known as CT scans, MRI data, and to a lesser extent computed tomography angiography (CTA) and magnetic resonant angiography (MRA). Each approach has pros and cons and therefore must be matched to the proper anatomy and end use.

CT scans comprise a series of x-rays evenly spaced laterally across a particular body section, typically generating several hundred image files. These can be quickly acquired and offer high resolution, however, they do not do well displaying different types of soft tissue, and the process relies on extended exposure to a radiation source.

Sample multiple digital images generated as a CT scan is performed (Image courtesy nymphoenix/Shutterstock.com.)

Typical CT resolution is 500 microns in X and Y directions, and 1mm in Z. This is readily handled by Stratasys printers; for example, the print resolution of the J750 Digital Anatomy Printer is 42 microns in X, 84 microns in Y, and 14 to 27 microns layering in Z, which more than captures all possible scanned features.

Computed Tomography Angiography (CTA) involves the same equipment but uses a contrast agent. With this approach, brighter regions highlight areas with blood flow. This process is superior for showing blood vessels but does not differentiate tissue or bones well.

MRI data is based on a different technology where a strong magnetic field interacts with water in the body. This approach differentiates soft tissue and shows small blood vessels but is more expensive and not effective for capturing bone. Similarly, Magnetic Resonant Angiography (MRA) uses a contrast agent that can track small blood vessels which are important for identifying a stroke but cannot register tissue. MRI scans may also include distracting artifacts and offer poor regional contrast.

A final source of digital imaging data is Positron Emission Tomography (PET). Here, radioactive material is attached to a biologically active area such as cancer; the data obtained with sensors is useful but very local – it does not show surrounding tissue.

Segmentation: Conversion from DICOM to STL format

Whether generated by CT or MRI equipment, anatomic image data is stored in digital files in accordance with the Digital Imaging and Communications in Medicine (DICOM) standard. Two aspects of this standard are relevant to 3D printing medical models: DICOM files include patient-specific, HIPPA-protected information, and the data in the individual images must be merged and converted into a solid model, with the areas of interest defined and partitioned.

Various software packages and services are available that will convert DICOM data into an STL model file (standard format for 3D printer input) while stripping out the personal identifying information. (The latter must be done to comply with HIPPA regulations: never send a DICOM file directly to any service bureau.)

Segmentation involves partitioning a digital image into distinct sets of pixels, defining regions as organ, bone, blood vessel, tumor, etc., then grouping and combining those sub-sections into a 3D model saved as an STL file. Not only does this format offer more meaningful information than a stack of separate images, but it can then be exported for 3D printing.

Example of processed CT scans, combined into a multiple-view 3D visualization and saved as an STL file. (Image courtesy PADT Inc.)

The standard unit of measure for identifying and segmenting the different regions within the combined 3D series of CT scans is a Hounsfield unit. This is a dimensionless value, defined as tissue density/x-ray absorption; for reference, water = zero, a kidney =+40 and bone = +1000.

Human guidance is needed to set threshold Hounsfield levels and draw a perimeter to the area of interest. You can define groups with the same threshold level, cut out certain areas that are not needed (e.g., “mask” the lungs to focus on the spine), and use preset values that exist for common model types. Typically, a radiologist or trained biomedical engineer performs this task, since correctly identifying boundaries is a non-trivial judgement task.

A particularly challenging task is the workflow for printing blood vessels, as opposed to bones or organs. The output from CTA/MRA imaging is the blood pool, not the enclosing vessel. In this case, users need third-party software to create a shell of X thickness around the blood pool shape, then keep both model files (pool and vessel) to guide printing the vessel walls and their internal support structure (which, on the Stratasys J750 Digital Anatomy Printer, is soluble and dissolves out.)

So far, just a few medical segmentation software packages exist:

  • Materialise Mimics Innovation Suite is internationally known for its excellence in image analysis and allows you to write scripted routines for automating repeated aspects of the segmentation tasks. There are also tools for interpreting images with metal artifacts, designing support connections between parts, measuring specified features, and rendering a view of the resulting 3D model.
  • Synopsys Simpleware ScanIP is a 3D image segmentation, processing, and meshing platform that processes data from MRI, CT, and non-medical imaging systems. Simpleware ScanIP removes or reduces unwanted noise in the greyscale images, allows cropping to the area of interest, supports both automated and user-guided segmentation and measuring and includes API scripting. Modules are available for Cardio, Ortho, and Custom solutions.
  • Invesalius 3 is open-source software that can reconstruct CT and MRI data, producing 3D visualizations, image segmentation, and image measurements in both manual and semi-automated modes.
  • Embodi3D/Democratiz3D is an online service that lets you upload a series of CT scans, select a basic anatomy type (bone, detailed bone, dental, muscle, etc.), choose the free medium-to-low resolution or paid high resolution conversion service, and receive the link to an automatically generated STL file. (Users do not interact with the file to choose any masking, measuring, or cropping.) The website also offers downloadable 3D printable models and 3D printing services.

Note that these packages may or may not have some level of 510K FDA clearance for how the results of their processing can be used. Users would have to contact the vendors to learn the current status.

Setting up the STL file for printing

Most of the segmentation software packages give you options for selected resolution of the final model. As with all STL files, the greater the number of triangles, the finer the detail that is featured, but the model size may get too large for reasonable set-up in the printer’s software. You may also find that you still want to edit the model, either to do some hole repairs or smoothing, slice away a section to expose an interior view, or add mechanical struts/supports for delicate and/or heavy anatomy sections. Materialise Magics software will do all of this readily, otherwise, adding a package that can edit STL files or create/merge geometry onto an STL file will be useful.

Medical Modeling software workflow from CT scan to print, for typical Stratasys 3D printed model.

Whoever is setting the file up for printing needs to make a number of decisions based on experience. For Stratasys Connex3, J55, J8-series or J750 Digital Anatomy Printers, the process begins by bringing the file into GrabCAD Print and deciding on an optimized build orientation. Next, colors and materials are assigned, including transparent sections, percentages of transparent colors, and flexible/variable durometer materials, which can be for a single part or a multi-body model.

For the J750 Digital Anatomy Printer in particular, users can assign musculoskeletal, heart, vascular, and general anatomies to each model, then choose detailed, pre-assigned materials and properties to print models whose tactile response mimics actual biomechanical behavior, such as “osteoporotic bone.” (see Sidebar).

I tested out the free online Democratiz3D segmentation service offered by Embodi3D. Following their tutorial, I was able to convert my very own DICOM file folder of 267 CT images into files without patient ID information, generating a single STL output file. I chose the Bone/Detailed/Medium resolution option which ignored all the other visible anatomy then brought the resulting model into the free software Meshmixer to edit (crop) the STL. That let me zero in on a three-vertebrae section of my lower spine model and save it in the 3MF format.

Lastly, I opened the new 3MF file in GrabCAD Print, the versatile Stratasys printer set-up software that works with both FDM (filament) and PolyJet (UV-cured resin) printers. For the former case, I printed the model in ivory ASA on an F370 FDM printer, and for the latter, I was able to assign a creamy-grey color (Red248/Green248/Blue232) to give a bone-like appearance, printing the model on a J55 PolyJet office-environment printer.

GradCAD Print software set-up of 3MF vertebrae model, ready for printing in a user-defined bone color on a Stratasys J55 PolyJet full-color 3D printer. (Image courtesy PADT Inc.)
3D printed vertebrae parts created from CT scans: on left, ABS part from a Stratasys F370 FDM printer; on right, Vero rigid resin material from a Stratasys J55 PolyJet printer. (Image courtesy PADT Inc.)  

Experience helps in producing accurately segmented parts, but more features, such as AI-enabled selections, and more online tutorials are helping grow the field of skilled image-processing health professionals. Clarkson College (Omaha, NE) also recently announced the first Medical 3D Printing Specialist Certificate program.

Reach out to PADT to learn more about medical modeling and Stratasys 3D printers.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

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Sidebar: J750 Digital Anatomy Printer

The Stratasys J750 Digital Anatomy Printer uses PolyJet resin 3D printing technology to create parts that mimic the look and biomechanical response of human tissue, organs and bones. Users select from a series of pre-programmed anatomies then the material composition is automatically generated along with accurate internal structures. Pliable heart regions allow practice with cutting, suturing and patching, while hollow vascular models support training with guide wires and catheters. General anatomy models can replicate encapsulated and non-encapsulated tumors, while bone structures can be created that are osteoporotic and/or include regions that support tapping, reaming and screw insertion.

Currently the Digital Anatomy Printer models present in the range of 80 to 110 Hounsfield Units. Higher value materials are under development which would help hospitals create phantoms for calibrating their CT systems.

Currently available Digital Anatomy Printer   Model/Section Assignments:

Structural Heart:

  • Clot
  • Frame
  • Myocardium
  • Reinforcement
  • Solid Tumor
  • Valve Annulus
  • Valve Chordae
  • Valve Leaflet
  • Valvular Calcification
  • Vessel Wall

General Anatomy:

  • Dense connective tissues
  • Hollow internal organs
  • Solid internal organs
  • Solid Tumor

Blood Vessels:

  • Clot
  • Fixtures
  • Frame
  • Gel Support
  • Inlets
  • Reinforcements
  • Solid Tumor
  • Valve Annulus
  • Valve Leaflet
  • Vascular Calcification
  • Vessel Wall

Musculoskeletal

  • Facet Joints
  • General Bone
  • Intervertebral Discs
  • Ligament
  • Long Bone
  • Nerves
  • Open End
  • Ribs
  • Skull
  • Vertebra

All Things Ansys 079: The State of Simulation for Additive Manufacturing

 

Published on: January 11th, 2021
With: Eric Miller & Brent Stucker
Description:  

In this episode your host and Co-Founder of PADT, Eric Miller is joined by Brent Stucker, the Director of Additive Manufacturing at Ansys to discuss the innovative capabilities of the Ansys additive suite of tools and it’s impact on the effectiveness of 3D printing for manufacturing and design.

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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@ANSYS #ANSYS

Discussions on the Past, Present & Future of Optimizing Topology for Manufacturing – Webinar

Traditional design approaches don’t make the most of new manufacturing methods, like additive manufacturing, which are removing design constraints and opening up new possibilities. The optimal shape of a part is often organic and counterintuitive, so designing it requires a different approach.

Topology optimization lets you specify where supports and loads are located on a volume of material and lets the software find the best shape.

Kick off the year by learning about one of the most exciting advancements in modern design and manufacturing. Join experts from PADT and nTopology for an interactive roundtable discussion on the ins and outs of topological optimization.

Register Here

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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!

Understanding Honeycomb Structures in Additive Manufacturing – Three Papers from ASU and PADT

PADT is currently partnering with Arizona State University’s 3DXResearch group on exploring bio-inspired geometries for 3D Printing. As part of that effort, one of our engineers involved in the project, Alex Grishin, PhD, was a co-author on several papers that have been published during this project.

Below is a brief summary from Alex of each article, along with links.


An Examination of the Low Strain Rate Sensitivity of Additively Manufactured Polymer, Composite and Metallic Honeycomb Structures

PADT participated in the research with the above title recently published in the open-access online journal MDPI ( https://www.mdpi.com/1996-1944/12/20/3455/htm ). This work was funded by the America Makes Program under a project titled “A Non-Empirical Predictive Model for Additively Manufactured Lattice Structures” and is based on research sponsored by the Air Force Research Laboratory under agreement number FA8650-12-2-7230.

Current ASU professor and former PADT employee Dhruv Bhate was the Lead Investigator and wrote the original proposal. Dhruv’s research interests involve bio-inspired design (the study of structures found in nature to help inform human design efforts) and additive manufacturing. Dhruv is particularly interested in the bulk properties of various lattice arrangements. While investigating the highly nonlinear force-deflection response of various additively manufactured honeycomb specimens under compression, Dhruv discovered that polymer and composite honeycombs showed extreme sensitivity to strain rates –showing peak responses substantially higher than theory predicts at various (low) strain rates. This paper explores and quantifies this behavior.

The paper investigates hexagonal honeycomb structures manufactured with four different additive manufacturing processes: one polymer (fused deposition modeling, or material extrusion with ABS), one composite (nylon and continuous carbon fiber extrusion) and two metallic (laser powder bed fusion of Inconel 718 and electron beam melting of Ti6Al4V). The strain rate sensitivities of the effective elastic moduli, and the peak loads for all four processes were compared. Results show significant sensitivity to strain rate in the polymer and composite process for both these metrics, and mild sensitivity for the metallic honeycombs for the peak load.

PADT contributed to this research by providing ANSYS simulations of these structures assuming viscoplastic material properties derived from solid dog-bone test specimens. PADT’s simulations helped provide Dhruv with a proposed mechanism to explain why INSTRON compression tests of the honeycomb structures showed higher peak responses (corresponding to classical ultimate stress) for these specimens than the solid specimens.


Bioinspired Honeycomb Core Design: An Experimental Study of the Role of Corner Radius, Coping and Interface

PADT participated in the NASA-funded research with the above title recently published in the open-access online journal MDPI (https://www.mdpi.com/2313-7673/5/4/59/htm ). This work was guided by former PADT engineer and current ASU Associate Professor Dhruv Bhate.  Professor Bhate’s primary research interests are Bio-Inspired Design and Additive Manufacturing. It was only natural that he would secure a grant for this research from NASA’s  Periodic Table of Life ( PeTaL) project. To quote from the website, “the primary objective…is to expand the domain of inquiry for human processes that seek to model those that are, were or could be found in nature…”

This paper focuses on the morphology of bee honeycombs found in nature –the goal being to identify key characteristics of their structure, which might inform structural performance in man-made designs incorporating similar lattice structures. To this end, the paper identifies three such characteristics: The honeycomb cell corner radius, the cell wall “coping” (a localized thickening of the cell wall at the mouth of each cell seen in a lateral cross-section), and the cell array “interface” (a zigzag pattern seen at the interface of two opposing, or “stacked” arrays).

Most of this work involved material testing and measuring dozens of natural honeycombs (most coming from various museums of natural history found in the United States) at ASU’s state-of-the-art facilities. PADT  contributed substantially by verifying and guiding tests with simulation using the ANSYS suite of software.


A Comparison of Modeling Methods for Predicting the Elastic-Plastic Response of Additively Manufactured Honeycomb Structures

PADT participated in this research found in the reviewed article published in Proceedings of the 29th Annual International Solid Freeform Fabrication Symposium – An Additive Manufacturing Conference.

Figure 14. (left) 2D plane strain model with platens connected to honeycomb with frictional contacts and (right) close-up of an individual cell showing the mesh size as well as corner radius modeled after experimental measurements

The lead investigator was current ASU professor and former PADT employee Dhruv Bhate, whose research interests involve Bio-Inspired Design (the study of natural structures to help inform human design processes) and Additive Manufacturing. In this research, Dhruv investigates discrepancies between published (bulk) material properties for the Fused Deposition Modeling (FDM) of ABS honeycomb structures. The discrepancies arise as substantial differences between published material properties, such as Young’s Modulus and yield stress, and those determined experimentally from FDM dog-bone specimens of the same material (which he refers to as “member” properties).

Figure 4. (left) Homogenization enables the replacement of a cellular material with a solid of effective properties, (right) which can greatly reduce computational expense when simulating engineering structures

PADT’s role in this research was crucial for demonstrating that the differences in base material characterization are greatly exacerbated in nonlinear compression simulations of the ABS honeycomb structures. PADT used both the manufacturer’s published properties, and the dog-bone data to show substantial differences in peak stress under the two assumptions.