Many companies and freelancers currently want to use digital twins to simulate the mechanical behavior of products or manufacturing processes before the first real prototypes are produced.

By using digital twins or simulation, you are one step ahead of the competition. I had already described this in this article (CLICK).

Unfortunately, many companies and freelancers still do not use digital twins, even though this could give them a significant competitive advantage.

This is because in many cases digital twins are built using FEM or CFD simulation. Simulation software is required for this purpose.

Many companies and freelancers are reluctant to use commercial simulation software because of the high licensing costs.

Do you feel the same way? You want to use FEM Simulation? But the fixed costs for commercial simulation software are too high for you?

FEM Freeware is your way out of this conflict and this blog article will show you how to get started quickly and safely.

What is FEM Freeware?

Surely you have heard of freeware or open source software.

I mean software that you may use completely free of charge.

The LINUX operating system is the most popular example here. LINUX is published under the GNU General Public License (GPL).

Software published under GPL may be used free of charge without restriction for private and commercial purposes.

So a powerful simulation software released under the GPL license you may use free of charge for all your commercial simulation projects.

This saves you the licensing costs for commercial simulation software.

I recently told the managing director of a design office about this during a consultation. He has had customer requests requiring the use of simulation for some time. However, the high license fees for commercial software have always deterred him. He usually had to turn down these orders.

Do you know what he answered?

“I have been thinking for a while if there is a simulation software that you can use for free similar to LINUX. But I never looked for it, because I thought that would be too good to be true or it has then some hook.”

I could tell him:

“Yes! There is a powerful simulation software that is suitable for industrial use and that they are allowed to use commercially free of charge without any restrictions. And there’s no catch to it.”

He was totally enthusiastic and it gives me a lot of pleasure to be the bearer of such great solutions.

In the next step, however, I am always asked:

“If FEM freeware is free and powerful, why does anyone use commercial software at all?”

We will deal with this in the next section.

Why is FEM freeware so rarely used?

In my experience, there are two reasons for this:

• FEM freeware is largely unknown because no one advertises it.
• Many have reservations about using FEM freeware.

The developers of FEM freeware or free software in general have no profit-making intentions. It is therefore only understandable that they cannot or do not want to invest much time or money in advertising their free software.

Potential users usually only learn about FEM freeware when they specifically search for it or when the software is recommended to them.

Many potential users who learn about FEM Freeware in these ways are enthusiastic, but also skeptical.

Deeply anchored in all of us are two basic principles of a capitalist society:

• Compared to expensive commercial simulation software, FEM freeware can only be much worse, simply because it does not cost money.
• If someone gives us something for free, there can only be some catch.

In many cases, this is true. To understand why it is not so with FEM freeware, we need to understand the philosophy of those who develop open source software.

The open source community is not about making money with the software. Developers earn money in other ways or do this work as a hobby.

For example, there are also companies that provide internally developed software to the open source community.

The goal is to promote the further development of the software by giving external users and developers access to it. The circle of users in the company is usually quite small.

The goal is usually also that everyone can benefit from the software free of charge and for this everyone who has the possibility contributes something.

In our capitalist-driven world, this may sound utopian. But that is the philosophy of the open source community.

It has been proven to work excellently for decades, bringing ever more powerful software to the application.

To eliminate our reservations about FEM freeware and fully benefit from it we need to understand this philosophy.

Once potential users are convinced, they usually ask:

“What FEM freeware would you recommend for me?”

We will deal with this in the next section.

How to choose the right FEM freeware

We must first agree on two things:

• There is a large amount of free software available. This amount is dynamic, because anyone can offer free software for download.
• There is no mandatory quality control. Therefore, there are serious differences between the available FEM freeware.

Thus, whether you use FEM freeware successfully or not depends largely on whether you choose the right FEM freeware from the large amount of tools available.

Bad experiences with FEM freeware are often based on the decision for an unsuitable software.

Essentially, an FEM freeware must meet the following criteria so that you can use it successfully:

1. You must be allowed to use the FEM freeware without any restrictions. Not only privately, but also commercially.
2. It must be ensured that the FEM freeware is permanently freely available and is also regularly further developed.
3. There must be a transparent quality assurance process to ensure that simulation results are valid. This is also the prerequisite for the FEM Freeware to be recognized by the authoritative testing bodies (e.g. TÜV).
4. You must be able to model your technical systems with the FEM freeware, i.e. solve your company-specific problems.
5. The usability must be so high that you and your employees can comfortably use the FEM freeware in everyday industrial life.

When I founded the engineering company Vonstein & Partner in 2012, it was clear from the start that I would need unrestricted access to simulation software for this purpose. You can find the whole story here (CLICK).

However, it was also clear that I could not afford commercial simulation software such as ANSYS or ABAQUS at the beginning.

I was researching FEM freeware and faced the same challenge.

I had to choose a FEM freeware that I invest time in and that will serve me well in the years to come.

I chose Salome-Meca at that time and I am absolutely satisfied with this decision to this day.

I have used Salome-Meca on every FEM project since 2012. And these were very many completely different simulation projects.

Among the many FEM freeware available today, Salome-Meca occupies a special status. I will explain why in the following.

Salome-Meca combines the pre- and post-processor Salome and the powerful FEM solver Code Aster in one simulation environment.

The FEM freeware has been developed since 1989 by the French utility Életricité de France SA (EDF) and was then released as open source software in 1999 under the terms of the GPL.

This means: You may use Salome-Meca commercially free of charge without any restrictions!

Salome-Meca is not a “fun project” of hobby programmers or PhD students.

The FEM freeware is used by EDF to analyze highly safety-critical components in nuclear plants and must therefore meet high safety standards.

For this purpose, the software is regularly verified and validated with over 6,000 test cases (including NAFEMS benchmarks).

About 70 engineers at EDF work with Salome-Meca every day to further develop power plant components. The software is also in use at EDF’s suppliers

An average of 30 engineers and programmers work permanently on the further development of Salome-Meca and Code Aster. On this basis, a new free version is released every year.

The spectrum of applications ranges from classical nonlinear solid mechanics to thermal analyses and the special fields of acoustics.

With the FEM Freeware all usual industrial problems in the mechanical engineering and mechanical engineering-near industries can be worked on therefore

The above points make Salome-Meca recognized by all testing bodies.

In short, Salome-Meca thus meets all the above criteria, has excellent usability and is also easy to install.

If you don’t want to spend a long time looking for a suitable FEM freeware yourself, then Salome-Meca is my hot tip for you.

That’s why I’ll explain below how to get started using Salome-Meca quickly and safely.

Installation of the FEM freeware Salome-Meca

Salome-Meca and Code Aster were originally developed by EDF for the LINUX open source operating system. The FEM freeware could therefore for a long time only be used by companies and freelancers who had at least one LINUX computer.

For many companies and freelancers, this was an insurmountable barrier to entry. The growing IT security requirements make it impossible to operate a LINUX computer in many companies.

In addition, many potential users shy away from using LINUX for no good reason. We’re all just very used to Windows.

So a Windows version was needed to lower the barrier to entry and further promote distribution.

As part of a crowdfunding, the developers of SimulEase have created a Windows version of Salome-Meca. For the Windows version the same license conditions apply as for the LINUX version.

So you can also use the Windows version free of charge for unrestricted commercial use!

For more information on crowdfunding (CLICK), click here!

All information about the installation of the current version Salome-Meca 2021 can be found here (CLICK)!

If you are interested in the LINUX version of the FEM freeware Salome-Meca, then you will find here (CLICK) all necessary information for the installation.

After you have successfully installed the FEM freeware Salome-Meca you will want to use it immediately to solve your problems.

Therefore, below you will find the best tips you can use to get started.

How to get started with the FEM freeware Salome-Meca

One of the most appealing advantages of FEM Freeware is that there is a large amount of high quality educational materials that you can use to learn the software application for free or at a low cost.

It is part of the open source philosophy that users share their knowledge free of charge with the rest of the open source community. Often in the form of YouTube tutorials or e-books that are offered for free download.

Another advantage is that FEM Freeware has open interfaces and can therefore be easily combined with each other. The Salome-Meca holistic simulation environment is thus just one way to use Code Aster.

As described above, Salome-Meca combines the Salome preprocessor with the FEM solver Code Aster.

For understanding, we divide preprocessing into its substeps:

• Geometry preparation
• Meshing (discretization)
• Model definition

For geometry preparation and meshing there is alternatively the possibility to use the open source preprocessor Gmsh, to name just one variant.

There are also several possibilities with regard to the model definition. A basic distinction is made between two paths:

• Model definition via an input file: Boundary conditions and loads are defined in a text file. A predefined syntax must be followed for this. The FEM Solver reads this text file and interprets the individual commands.
• Model definition via a graphical user interface: The model is thus “clicked together”. The graphical user interface then creates the input file and makes it available to the FEM solver.

Beginners mostly prefer model definition via a graphical user interface. This way, they don’t have to learn the syntax of the input file in parallel to all the other challenges.

With increasing professionalization, most users then switch to model definition via an input file, as this procedure is more effective and easier to automate.

The FEM freeware Salome-Meca has the advantage that both approaches are supported. The integrated tool AsterStudy enables a fully graphical model definition. In addition, AsterStudy also facilitates the switch to model definition via input file.

So what we can state is:

• There are different workflows for running a simulation project.
• They have different advantages and disadvantages.

The reason why I am writing about it in such detail at this point is as follows:

All the teaching materials you find on the Internet favor a particular workflow.

So, if you are looking for educational materials on the Internet, do the following:

• Determine the work flow that is right for you at the moment.
• Then, look specifically for instructional materials that support your selected work flow.

I always recommend beginners to use Salome for preprocessing and to do the model definition fully graphically via AsterStudy. In our introductory seminars, we have found that this is the best way to get started.

In my recommendations below, I therefore pay particular attention to which preprocessor and which variant of model definition the teaching materials favor.

If you are looking for more in-depth information on the work flow of a finite element analysis, I recommend the book“Pratical Finite Element Analysis for Mechanical Engineers” by Dominique Madier.

Or attending our seminar “Introduction to Finite Element Analysis of Assemblies with Salome-Meca and Code_Aster“.

Here we go into detail about the work flow of the entire simulation project.

I recommend our introductory seminar or the book by Dominique Madier also to acquire necessary simulation know-how beyond the software application.

This refers, for example, to expertise in mechanical modeling or stress evaluation.

The best teaching materials for FEM freeware Salome-Meca

YouTube tutorials

Highly recommended are the YouTube tutorials by Cyprien Rusu. With his project “FEAforAll” he makes a great contribution to Simulation Democratization.

In his tutorials on Salome-Meca he follows 1:1 the work flow recommended above.

Here (CLICK) you can go directly to his YouTube channel, which also contains many exciting tutorials about simulation aside from the software application.

Click here (CLICK) to go directly to his Salome-Meca tutorials.

E-books from Dharmit Thakore

Dharmit Thakore’s textbooks are not free, but they are very inexpensive. They are based 1:1 on the work flow recommended above. Dharmit explains the use of the FEM freeware Salome-Meca in an easy to understand and very entertaining way.

If you are serious about using the FEM freeware Salome-Meca, you will find these books an inexpensive way to get started. The books contain almost exclusively exercises. If you work through the books completely, you will be quite a bit further along.

Click here (CLICK) to go directly to the download.

E-book by Jean-Pierre Aubry

The free e-book

“Beginning with code_aster – A practical introduction to finite element method using code_aster and Gmsh“.

by Jean-Pierre Aubry gives an excellent overview of the functional spectrum of Code Aster and a lot of background information on 351 pages.

The only disadvantage for beginners is: The book favors a work flow with the preprocessor GMSH and model definition via input files. Knowing this, however, it is still quite suitable as a supplementary reference book.

You can download the book here (CLICK) for free.

Code Aster Forum

If you have individual questions, I can highly recommend the Code Aster Forum. Here the developers of Code Aster write and support themselves. In addition, many questions have been asked before.

So, in the existing articles you can already find solutions for many known challenges. Create an account and ask your question. I am sure you will be helped.

Click here to go directly to the forum (CLICK).

With the aforementioned teaching materials, you can become autodidactically acquainted with the FEM freeware Salome-Meca. This procedure has the advantage that it is very cost-effective but sometimes very time-consuming.

Additionally, self-taught learning is not suitable for everyone. Some prefer to attend seminars.

A good seminar can extremely shorten the time needed to build up know-how, because the instructors tailor the knowledge to your individual starting situation and requirements.

Are you looking for an opportunity to learn how to use the FEM freeware Salome Meca and additionally the necessary theoretical basics within 3 days?

Then our seminar

“Introduction to Finite Element Analysis of Assemblies with Salome-Meca and Code_Aster“.

just the thing for you! We offer the seminar in presence and as an online event.

Click here to go directly to the seminar description.

That brings us to the end of this blog article. I hope I was able to teach you in an understandable and entertaining way how to quickly and safely get started using FEM Freeware and thus be one step ahead of your competitors in the future.

Do you feel you can get started right away or is something still holding you back from using simulation in your product development? Do you have any questions or suggestions?

I look forward to your comments!

Der Beitrag OpenSource FEM – Get started quickly and safely and stay one step ahead of the competition erschien zuerst auf Vonstein & Partner.

For this year’s Christmas simulation, we carried out a numerical modal analysis with the FEM freeware Salome Meca. Today I would like to introduce you to Pfeffi . Pfeffi is a gingerbread man, is approx. 400 mm tall and is made of aluminum (E = 70,000N / mm²). For our Christmas simulation we were able to persuade Pfeffi to undergo a numerical modal analysis. Additional dimensions in his arms and legs inspire Pfeffi to adopt the following eigenmodes:

• Say-Yes-Mode: 397 Hz
• Walk mode: 445 Hz
• Run mode: 1,152 Hz
• Say-No-Mode: 1,430 Hz
• Dance mode: 1,963 Hz
• Merry Christmas mode: 2.129
• Sports mode: 2,423 Hz

The modes are visualized one after the other in the following video:

Which of Pfeffi’s Eigenmoden do you like best? Write us a comment!

Do you fancy your own Christmas simulation? We would be happy to share Pfeffi’s step file and the associated simulation model from the free FEM software Salome Meca with you! Just write me a message for this. Remember: Different additional masses lead to different modes. Maybe you can create even funnier gingerbread man fashions.

Our Christmas simulation was created in collaboration with our cooperation partners and good friends from WS Product Development . Thank you Mathis for giving Pfeffi a life as a virtual prototype.

Numerical modal analysis with the FEM freeware Salome Meca (Code_Aster)

The dynamic behavior of components and assemblies often causes unpleasant surprises in industrial practice. This is particularly the case when assemblies that were only statically loaded in the past are suddenly subjected to dynamic loads. If the component is excited at one of its natural frequencies, the loads increase unexpectedly. This usually leads to failure of the component and possibly also damages the surrounding structure. For example, during an earthquake, surface movements can cause a pressure vessel to vibrate strongly and thus cause damage with disastrous consequences. Fortunately, the natural frequencies and natural modes can be determined with the numerical modal analysis, a procedure based on the finite element method, even before the first implementation on the virtual prototype.

With the numerical modal analysis, we can quickly and easily ensure that assemblies are not excited in their natural frequencies later during operation and thus go into resonance. In addition, the natural frequency calculation is used to check whether static equivalent loads may be used for strength proofs of dynamically loaded systems.

For the implementation of our Christmas simulation and for the numerical modal analysis in general, we use the FEM freeware Salome Meca with the open source FE solver Code_Aster. Together, both software tools result in a powerful simulation environment for structural dynamics and many other classic applications of finite element analysis.

FEM Freeware has the advantage that we and our customers can use it commercially free of charge without any restrictions. So without software license costs!

With this in mind, we are now going into the Christmas break with our blog. Next year we will be back with a blog article about flow simulation and the analysis of fluid-structure interactions. We wish you a Merry Christmas and then a good start into the New Year.

Der Beitrag Numerical modal analysis – Christmas simulation 2021 erschien zuerst auf Vonstein & Partner.

Industry 4.0 is driving digitalization in the product creation process

It is to be expected that the development of new interface standards and a separate language for the communication of the digital twins will have very practical effects for SMEs in the near future. To understand the scope of this development, you only need to think, as an example, of how natural it is for designers to download CAD files for purchased parts today. In the past, the catalogs of the manufacturers of machine components such as screws, valves and safety switches were enough for him. Today he naturally expects to find the CAD files of these machine components for download on the Internet so that they can be copied into his own CAD models. Manufacturers who do not offer the CAD files of their products for download in known formats such as IGES, STEP and VDA-FS are in a difficult position. A similar development can be expected in Industry 4.0. Only those who are able to let their own digital twins, virtual prototypes and simulation models communicate with those of other manufacturers and customers will stay on the ball.

Concerted action creates clarity – Industry 4.0 platform

Under the leadership of the Federal Ministry for Economic Affairs and Energy , the Federal Ministry for Education and Research and a number of well-known industrial associations and companies, the Industry 4.0 platform is developing a comprehensive range of information and strategies for the digital transformation of production in Germany. Based on the Industry 4.0 platform and other sources, we give here our understanding of the terms digital twin, virtual prototype and simulation. Our presentation does not claim to be complete or general, but is intended to make it easier for you to read our articles.

Differences between digital twin, virtual prototype and simulation model

Digital twin

As we understand it, the digital twin is a data container, also known as an administration shell. It stores the data that is collected in the course of a product life cycle. The storage takes place in so-called partial models. Each partial model stands for the data of a specific application that is generated for the development, production, sales and maintenance of a product. The digital twin is a virtual model of the real product. It differs from the virtual prototype in the additional data stored for the manufacture, use and maintenance of the product and its individual instances.

Virtual prototype

As a virtual prototype, we understand the counterpart to the real prototype. The virtual prototype is a digital model of a machine part or product. In addition to the CAD geometry, it can include one or more simulation models. Depending on the level of detail of the virtual prototype, simulation models for mechanics, thermodynamics, flow and many other physical subjects can be assigned. The virtual prototype is a partial model of the digital twin.

Simulation model

The simulation model consists of the geometric model, the selected physical laws, the settings for the calculation and many other parameters. In addition, there are the calculation results, if necessary data for validation and records of the evaluations and derived measures.

Simulation methods – tools for creating virtual prototypes

In digitized product development, virtual prototypes are intended to replace real prototypes in order to save costs and enable early, reliable decisions. Simulation methods such as FEM, CFD and MKS are tools for creating virtual prototypes in product development. Even if they are not referred to as virtual prototypes in everyday language within a company, they are often already there in the form of CAD files, simulation models and other records. Illustration – … Like their real counterparts, virtual prototypes have to be created with tools. The tools for creating virtual prototypes are provided by the simulation methods. They contain data on geometry, material, boundary conditions, loads, applicable physics (mechanics, temperature, vibration), settings for the calculation (step sizes, number of CPUs, termination criteria), calculation results, comments and much more individual information for the virtual prototype to create and manage. Simulation methods map the physical behavior of a virtual prototype by solving the systems of equations after the model has been created. In the following sections, we’ll give you a brief overview and we’ll look at some of these methods in more detail in upcoming blog posts .

Collision check in CAD

An early field of application of virtual prototypes was the collision check of components in CAD. The CAD models of side-by-side components were checked for penetration and assemblability to ensure they had enough space. This already represents a simple form of simulation with virtual prototypes. It could be carried out long before the completion of real prototypes and offered enormous cost advantages.

FEM in solid mechanics

The finite element method (FEM) is one of the best-known numerical methods for solving systems of equations in solid mechanics and other fields of engineering. It was first used in research and in large companies in the 1960s. Since the advent of powerful desktop PCs in the 80s, FEM has been widely used in mechanical engineering, process engineering, civil engineering and many other industries. Numerous physical phenomena and laws from mechanics, thermodynamics, vibration theory and other disciplines are mapped in the FEM and can be called up in the available FEM solutions. A large selection of FEM software is available in the form of commercial products and open source solutions (OSS). The process of an FEM application is divided into model creation (preprocessing), calculation run and result evaluation (postprocessing). The programs available today offer many functions for quick model creation. The learning curve for users is steep because working on their own range of products enables them to concentrate on a manageable selection of program functions.

CFD and FSI for flow simulation

Computational Fluid Dynamics (CFD) is an independent subject of simulation methods for flow simulation. Flow simulation uses Navier-Stokes equations, Euler equations, potential equations, and other systems that are solved using various numerical methods. For a long time, CFD was considered a topic with very high demands on the physical understanding of users and computer performance. In the meantime, CFD systems with comfortable user interfaces have been developed that support designers in many everyday simulation tasks. They run on the hardware customary in the design office, but also enable arithmetic runs on mainframes. With the connection of CFD and FEM fluid-structure-interactions (FSI) are to be investigated.

MKS / EMKS multi-body simulation

The multi-body simulation (MBS) is not quite as visually impressive, but no less important in practical use. In MKS, arrangements of rigid solids are considered almost independently of their real geometry. The aim is to investigate the kinematic system that the greatly simplified bodies form together with idealized articulations. The movement of the multibody systems is described by differential equations that are solved on the computer. If the elastic behavior of a solid cannot be neglected, it is called an elastic multi-body system (EMKS). It can be investigated with a coupling of the methods of MBS and FEM.

Digital twins, virtual prototypes and simulation models in industrial practice

In the simplest case, a virtual prototype is already mapped by a single simulation model and is used to clarify the open questions. A virtual prototype, which is used for a simple FEM simulation with a linear-elastic material law, can provide crucial information on the suitability of the design at an early stage in the product development process. Of course, a virtual prototype can also consist of several simulation models in order to capture different aspects of the physical behavior. One example is the virtual prototype of a machine tool with an FEM simulation model for the deformation of the frame, an MBS model for the dynamic behavior of spindle, tool, workpiece, drive and gear and a CFD model for cooling the process with cutting fluid.

Simulation models are an essential part of the digital twin

The digital twin is to be understood as a universal data container that accompanies a product type and its individual instances through the life cycle. It can contain one or more sub-models that are assigned to specific applications, such as a simulation program. If a simulation model is made for a calculation, such as for the linear-elastic simulation of a machine lever, a partial model is available in the digital twin for storing the input data and calculation results over the entire product life cycle. The attentive reader will wonder why simulation models are an “essential” part of the digital twin. From our point of view, the answer is quite simple: The simulation of the reaction of a machine component or virtual prototype turns a mere collection of data into a living object in virtual space. Its behavior in response to external and internal stresses can be studied with almost any degree of accuracy. The user turns from data collector to observer and gains deep insight into the functioning of the virtual prototype. Therefore simulation models are essential for the use of the digital twin.

Simulation models form the foundation for the virtual prototype

Simulation models form the basis for the virtual description of the physical properties of products and manufacturing processes. The description of the physical properties takes place in simulation models not only via individual parameters, but also via virtual functions, i.e. calculation runs that examine the physical behavior of the product and reproduce it in a way that is understandable for the observer, ie visually. The simulation is about the behavior of the virtual prototype, not just about rigid physical values such as color, height, weight, speed and connector type.

How do you see the role of simulation in the context of digitization and Industry 4.0? How do you understand the terms digital twin, virtual prototype and simulation model? We look forward to your feedback!

Der Beitrag Digital twin and virtual prototype in Industry 4.0 – simulation brings them to life erschien zuerst auf Vonstein & Partner.