Dear Reader,

I hope you are doing well. Let us get into this week's newsletter. I warn you, this is a longer than usual newsletter. Please feel free to skip to the sections that interest you the most.

The ABAQUS Unit complex

Most of the models I work on in the CM Videos Youtube Channel tend to be based on microstructural systems with dimensions in micrometer lengthscale. One question that I often get asked is how I deal with such dimensions and what is the unit system in ABAQUS for dealing with such microstructural lengthscales. The image below is my proposed thumbnail for a forthcoming video on this issue.

The reasons behind what I describe as "the ABAQUS unit complex" are worth considering are these:

• ABAQUS does not have an inherent unit system behind it. At best, it is a dimensionless software.
• ABAQUS sketching module does not accept lengthscales below 0.0001 units.
• Other FEA solvers (ANSYS, COMSOL) and CAD software (SolidWorks, Design Space) have a predetermined unit system so many users already have an exposure to working with units in their virtual domain design. So, working with a dimensionless software as ABAQUS can cause some modelling confusion.

Therefore, the key questions are:

These are some of the questions I have been thinking a lot about this week, and although I know the answer to them, I wanted to find a way to communicate what I know with you so that if anyone has such questions as the above, you will be able to get them answered.

Below are some of the distinct things associated with modelling with ABAQUS and understanding the type of units that is at play.

1. Unit Agnostic: There is no unit system behind an ABAQUS model. You decide what unit you want to work with. This unit agnosticism is not unique to ABAQUS but also applicable in other lesser known FE solvers as: Calculix, Cast3M, FEAP, StressCheck and Welsim.
2. Units inter-conversion competence: To work with ABAQUS, you must be able to convert from one unit to another. For example, if you are working with a micrometer unit system for lengths, then your stress measures normally in Pascal, Pa should be converted to units of N per squared micrometer units as I showed here+.
3. Paradoxical analysis of results: The third thing you should be able to do when working with non-standard units as micrometer in ABAQUS is what I describe here as the paradox of results analysis. Often times, when you look at results from a simulation where the units are non-standard, the values from the simulation will often appear at first analysis as wrong, but when you think of the unit at play, the size of the model and the meaning of the findings from the results, you will quickly undertand that actually the results are correct. For example, when I analysed a piece of steel with micrometer lengthscale, the results of the yield stress was 0.000250 N per squared micrometer. This seemed wrong but when you think of the micron length scale, then that means for every 1 squared micrometer units, then the steel material is subjected to a 0.000250 N, which then does not look wrong anymore.

Finally, I have just filmed a video about precisely this issue and hopefully that video will help you understand what unit system is behind an ABAQUS model. The above are some of the things that I will be discussing in that video. I will like you to watch out in future newsletters and videos on the CM Videos channel for when the said video is launched.

Behind the Scenes at CM Videos: Table of Content for PBC E-book

I finally finished putting together what I will like to be the desired table of content for my Periodic Boundary Conditions E-book. It is shaping up to be a lengthy book with, I hope, excellent material for my audience. I intend to make the book it a three-part book with the following parts

If you want to follow me in my writing journey or get directly in your email more details of the chapter-by-chapter breakdown of the E-book, then do sign up to my E-book writing newsletter via the link below.

Quote for the Week

At the start of the year, I read this brilliant book by Darren Hardy called The Entrepreneur's Rollercoaster. One of the things that struck me as I read it was the continued insistence of Darren for peopole who want to be successful in life generally to expect things not to be straight forward all the time.

Life is not always fair, someone once said. This is true! We do not always get what we deserve in life. So, no one ever can achieve success on their terms. Things come in between to try to scupper our plans: forestalling our ideas and aspirations.

However, for the truly successful, they are the ones who learn how to turn their ideas, inspirations and aspirations into perspirations. When we allow ourselves to work hard on a project, we make our own luck. This is the wisdom of my quote for the week.

I wish you a highly productive week where you stop complaining of what has not worked, but put in your best into whatever project you are working on right now and hopefully, you can begin to see your efforts result in overwhelming success. I am rooting for you!

That is it for another week. I am sorry for writing such a longer than usual newsletter. I guess I had a lot to say and the ideas were just flowing. Have a lovely weekend and catch you next week. Au revoir!