computer science

Radioss

Radioss is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Radioss rather than just read about it. In short: Altair Radioss is a multidisciplinary finite element solver developed by Altair Engineering. It includes implicit and explicit time integration schemes for the solution of engineering problems, from linear statics and linear dynamics to non-linear transient dynamics and mechanical systems.

Key takeaways

Radioss belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Radioss to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Radioss from memory before moving on to harder problems.

Reference excerpt

Altair Radioss is a multidisciplinary finite element solver developed by Altair Engineering. It includes implicit and explicit time integration schemes for the solution of engineering problems, from linear statics and linear dynamics to non-linear transient dynamics and mechanical systems. The multidisciplinary solver has its main strengths in durability, NVH, crash, safety, manufacturability, and fluid-structure interaction. Since the 2021 release, Radioss has supported input in the LS-DYNA input format as well as the Radioss 'Block' Format OpenRadioss, an open-source version of Radioss under the GNU AGPL license. OpenRadioss shares the capabilities, input and output formats of Altair Radioss. OpenRadioss was released on September the 8th 2022. OpenRadioss uses an external library that is partly provided in binary form. This external library contains open-source software like lapack and C++ Mathematical Expression Toolkit Library. But also free software like md5, zlib, and Altair's library for their h3d extension.

History Radioss originated from the 3D FEA program DYNA3D. DYNA3D was originally developed by Dr. John O. Hallquist at Lawrence Livermore National Laboratory (LLNL) in 1976. DYNA3D was publicly released upon a request of France. After DYNA3D was released, the ESI Group developed Pam-Crash. Some time later, Radioss split from Pam-Crash. This means that the LS-DYNA, Pam-Crash and Radioss all originate from the same base code. Abaqus, Pronto-3D, MSC DYNA, and DYTRAN also originate from DYNA3D. In september 2022, Altair made the decision to release Radioss also under the open-source GNU AGPL license. This means that Radioss is available both with a commercial license and an open-source license. OpenRadioss allows academia to implement new features in OpenRadioss which later can be ported to Radioss. This means that developments in academia go quicker to a commercial FEA program. Altair also has appointed a director of the OpenRadioss community, Marian Bulla. Besides this, OpenRadioss also has a steering committee with 13 members that include people from industry and academia.

Disciplines Linear static analysis Non-linear explicit dynamic analysis Non-linear implicit quasi-static analysis Normal modes analysis for real and complex eigenvalues Linear buckling analysis Frequency response analysis Random response analysis Linear transient response analysis Linear coupled fluid-structure (acoustic) analysis Linear steady-state heat transfer analysis coupled with static analysis Explicit Arbitrary Eulerian-Lagrangian (ALE) formulation Explicit Computational Fluid Dynamics (CFD) Smoothed-particle hydrodynamics (SPH) One-step (inverse) and incremental sheet metal stamping analysis

Material models Some of the material models available in Radioss are:

gases Metals Plastics Glass Foams Fabrics Rubbers Elastomers Polymers Honeycombs Concrete & soils turbulent and/or Viscous fluids Detonation products of high explosives porous material Springs Composite materials Glues User-defined materials

Element library Some of the element types available in Radioss are:

Beams (standard, integrated-beam, trusses, discrete, cables, and welds) Discrete Elements (Springs and Dampers) Lumped Masses Accelerometers Sensors Seat Belts Shells (3, 4-node) (with 3 shell element formulations, namely, Belytschko-Tsay, Batoz-Dhatt and Zeng-Combescure) but also shells for composites or sandwich materials. Solids SPH Elements Arbitrary Lagrangian Eulerian (ALE) Thick Shells (8-node) void (nothing)

Difference between Radioss and OpenRadioss Radioss and OpenRadioss are very similar to each other but there are some small differences. The differences are mostly relevant for the automotive industry. These are:

OpenRadioss does not have the encryption keyword which is used to read-in encrypted commercial crash test dummies. OpenRadioss does not have some airbag keywords. OpenRadioss does not have the interface with MADYMO, which is also commonly used for commercial crash test dummies. Other features of Radioss and OpenRadioss are nearly identical. OpenRadioss is the code that developers work actively on. This means that OpenRadioss commonly is ahead of Radioss but Radioss is tested better by Altair.

References

External links Altair Radioss webpage Altair Radioss User Documentation OpenRadioss webpage

Worked examples

Example 1 — a first encounter with Radioss

Start with the simplest possible case. Write down what Radioss claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Radioss before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Radioss ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Radioss

In research: Radioss appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Radioss in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Radioss is common in secondary-school and first-year university syllabi. It links to neighbouring topics Finite element software, Finite element software for Linux, Simulation software, so understanding it makes those chapters shorter.
In everyday life: Look for Radioss outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Radioss in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Radioss means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Radioss out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Radioss in simple terms?

Why does Radioss matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Radioss?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Radioss.