Five years ago, we posted a blog about analyzing a PET-bottle, including a top load analysis performed with Abaqus. This type of analysis is used to determine the maximal force a bottle can withstand under axial loading. In the current blog I want to revisit the topic, and focus specifically on materials properties. Often these are not readily available. Perhaps a data sheet is present, specifying a Young's modulus and a Yield stress (if you're lucky) but not the actual stress-strain data. Here we'll take a look at the impact of using limited material data on the limit load in a top load analysis.

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).

Personally, I find solving finite element problems way more interesting than installing the software, ensuring the hardware works and worrying about licenses. Unfortunately, hardware and licenses are needed to do the more interesting stuff. Therefore I’ll say a bit more about that in this blog.

I’ll go into the traditional options with standalone Abaqus as well as the running an .inp file using the 3D experience platform on the cloud.

From Simuleon we wish you a Merry Christmas and all the best for 2021!

And at least I am hoping for some snow ;)

Here in the Netherlands we have the expression that something can 'snow under'. Figuratively, this indicates that it's forgotten, because something else is taking up all the attention. Typically, this isn't a good thing, but in light of the current pandemic, it may not be a bad thing if we can forget 2020, hence this simulation with 2020 numbers ;-).

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.

Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mould, and trimmed to create a usable product (https://en.wikipedia.org/wiki/Thermoforming). Often a vacuum and maybe even a plug is used to help the sheet take the shape of the mould.