In this blog I wanted to explore the age-old question facing most FEA analysts: Is my model good enough? with examples from my PhD work in knee joint biomechanics.

To create an FE model and run it in a reasonable amount of time, several assumptions and simplifications are needed. One of the aims of one of the knee joint FE models I developed previously was to rapidly identify locations at risk of OA in a patient-specific manner. To achieve the rapid part we used simplified materials models for the main tissues in the knee joint, based on previous literature studies:

In this blog we have given the honour to Per Landeback as a special guest writer for our blog. Per has written this great blog about a parametrical Equation to calculate Rolling Resistance of a car tire.

BIO - Per Landeback

Retired test and simulation engineer with vast experience of various vehicles as car, bus, truck and train. Studied at Chalmers University of Technology and performed Master Thesis at a Volvo Aero military engine. Held previous positions as employee/consultant at SAAB, Volvo Truck, Volvo Bus, Bombardier, Scania Truck and NEVS (National Electric Vehicle Sweden). Technical aeras within Comfort, Handling, Braking, Steering, Suspension, Engine mountings, Tires and General component calculation/simulation

"Thank you for the invitation to write about tire rolling resistance and especially about my developed Parametrical Rolling Resistance Equation. This is considered as a first publication and it very likely a paper will be a published. Therefore, general Copywrite rules apply."

Abaqus has many built-in options but sometimes these do not suffice. You may want to include a material model that is not implemented, have a complex type of loading that is not available by default or even define your own element. Abaqus' user subroutine capabilities allow you to do this. User subroutines are written in Fortran and in order to use them, you need a Fortran compiler. In this blog I'll show how to install a freely available fortran compiler and link it to Abaqus. Thanks to Oliver Lundqvist working for Sweco in Finland for making me aware of this option, and to oaeres on https://community.intel.com/t5/Registration-Download-Licensing/How-to-link-ABAQUS-with-Intel-One-API-toolkits-to-run-FORTRAN/td-p/1244548/page/2 who provided this solution (especially the last workaround).

In this blog post, we will be looking into a different discretization method, available in Abaqus Explicit. This discretization method can prove to be really useful, in applications where gross distortions or large spatial displacements are expected to occur. A category of applications that can benefit from such a technology, are installations/decommissions of deep sea components, interacting with the seabed.

Abaqus 2021 is out. In this blog post, we will be showing some of the enhancements, that we found interesting. Additionally most major enhancements will be highlighted, for this new Abaqus release. For a more in depth explanation of the new enhancements, you can take a look in the release notes, provided here.

The discussed enhancements, are included in versions up to Abaqus 2021 FD03(FP.CFA.2042), which has been released. More  enhancements are scheduled for later releases of Abaqus 2021x.

In the hot rolling process, metal is heated and passed through one or more sets of rollers, to give it the desired cross-section for example. This process is used for the fabrication on railway tracks (Figure 1).

In this blog, we’ll take a look at an air spring (Figure 1). This device is used for vibration isolation as well as suspension, for example in heavy weight vehicle applications.

Figure 1: Example of an air spring.

The example shown here consists of a convoluted bellows (two convolutions), with steel plates on each end. In practice, one to three convolutions are used. The bellows is made of rubber that is reinforced with fibres. A steel girdle hoop helps to keep it in shape when it is filled with compressed air.

Sometimes the results I get from Abaqus are not what I expect. Perhaps the analysis does not complete while I didn't think it would be very troublesome, or I do get results, but they don't make sense to me. Though this can be very frustrating, it can also be seen as an interesting puzzle (especially if it is somebody else's problem ;) ). For that reason, I'd like to share some results with you that did not make sense to me. Let's see whether you can figure out what went wrong!

As a consultancy company, we regularly receive geometry files from external parties. Typically this geometry isn’t ideal for simulation purposes: it includes details that are not of importance for the analysis, while they will negatively impact meshing and simulation time. Therefore, it is beneficial to remove some of the features from the geometry (defeature it) for simulation purposes.

As you may have noticed, we're working on kind of a series of blogs on the simulation of different production techniques. This time, we will look at roll forming.

Roll forming

During the roll forming process, a long strip of sheet metal is continuously bent into the desired cross-section. The strip passes through a number of sets of rollers, where each set performs a part of the total desired bend, until the final profile is obtained.