The red candle cup.

Day and night is present in our lives since the moment of our birth. Place a lit candle in this cup and a world of reflection opens, giving a fantastic ambience. Light is all about sensation, math, physics and some mysticism at the mixture. Light has been studied by many geniuses from Albert Einstein to Richard Feynman giving birth to fantastic ideias about the universe around us, but a side from the speed of light, it’s diffraction  the common human knows little about it.

Many activities explore light, modelled it and play with it. Photography explores light to an outstanding level. Texture, highlights, color, black and white, grey toned images are just a few examples.

Unfortunately I don’t have much answers regarding light simulation and what can be done with it. Interestingly games play with light from rendering shadows, light glare, and more effects. Photo editing software also create lens flare effects, maybe these can be considered to be some sort of light modelling.

Either by exploring light on a nice summer day or by taking that photo at sun down, light remains the source of inspirations that holds still many secrets to tell.

Red_and_silver_Squared_Glued_Glass_Cup
Red and silver Squared Glued Glass Cup

Space Time warping, space and gravity waves near the kids pool

I took a nice day off to relax. Sitting near the kids pool i noticed the water lensing effect, warping the geometry of the pool’s little squares. Who would know that gravity waves stretch and compress but instead of a 2D picture it’s actually us. 3D bodies bending, stretching and who knows what more happen near the originators of these events. I wonder what models are used to describe gravity waves. Boundary conditions, assumptions…. Einstein new it all along, just with brain power.

Pool wobble
Pool wobble

 

And the race begins

The good old pioneering years have past and gave us mature numerical simulation packages to model physics. Universities and enthusiasts at the beginning helped craft the software and technology we see today. As these commercial options became evermore closed, new open source driven projects started to bloom some years ago.

The start might have been slow, with many limitations but each part of an integrated open source simulation environment was crafted.

These have evolved but tried to do a bit of everything, with the penalty of becoming too complex, since development priorities could not focus on all aspects: geometry, meshing, solving…

Today we start to see the end of the dark age and the beginning of a pungent evolution of these individual packages. Why?

Integration.

A base software integrates all individual necessary components and therefore each development team focuses on it’s special functional area. This evolved new approach will drive ultimately an increased software usage which will motivate more development.

So who are these integrators?

The first one will launch in September 2017 which is Salome-Meca, it will feature a complete integrated package: geometry, meshing, solving more polished and simple to use. Salome Meca 2016 already allowed some easy usage but was very limited and to go beyond required more coding.

FreeCAD 0.17 is improving from a FEM package that was very incomplete to a very versatile package having fluid, structural and thermal capabilities. Allows now also contact definition.

These packages will continue to grow at an accelerated pace and 2017 will be the turning point! Comercial software will have to adapt to this new reality.

Open VS Commercial
Open VS Commercial

The sycamore tree fruit

Everyday I ride my bike passing through so many interesting subjects but as always in a immense hurry. My grandmother always told me that haste makes waste and in honest truth when we slow down and really stop just to appreciate better whats around we see differently. Structures, detail and maybe sometimes have some inspiration.

I was in my running to work mode, fast and furious pedalling to the gates of hell, but then I noticed a sycamore fruit on the ground… I braked heavily and pick it up! I think it was worth my extra seconds. A very complex surface in a tiny area. Will we any day be able to mesh a structure this complex?

Top Sycamore Fruit
Sycamore Fruit

 

My Donuts and some wonderful work Wikipedia. Let’s help!

While strolling around NY (New York – Manhatten) I noticed a really pretty donut looking at me. I got really impressed with it’s design and colour set. This donut remembered me my, Advanced Math course back in the days I was studying, where we represented mathematically a torus. I opened my phone and viewed it’s equation without any cost. It was free and imediatly available in wikipedia. For me, one of the most marking human accomplishments in my life time. Everyone knows it! And in some direct or indirect way we use it (our children use it).

Torus cyclesLet’s all give some help and donate! 

My Dunkin Donuts
My Dunkin Donuts

The meshing dilema

Some times we use the default mesh and get happy with the result,s others we don’t. It is hard to develop a test setup or expensive to buy the test setup equipment to calibrate the model. On these cases that we can’t compare results we have to take simulation results as final. This presents a few chalenges since how do we know the model is good enough for our purpose? Normally I follow two paths either by analytically calculating a rough value or by carefully analysing mesh sensitivty, analysing energy balances and whatnot. Although it is tempting to take a rough model as final, bad consequences can come from that decision, since we can end up with divergent results that relate more to model deficiencies than to the actual physics in hand.
Look at this example where I have 3 result set’s for varying thicknesses, however with different meshing strategies.

Meshing Sensitivity
Meshing Sensitivity

Which of the lines is the truth? Just a small change and such a big difference. You have to trust me on this, there is a big difference 200MPa from bottom blue to top grey.

Measuring modeling validating testing where we stand

When I first started in a development department, measuring parts was done with simple tools like calipers, micrometers, dynamometers… new equipment started to appear resorting to 3D measurements automatic measurements with a computer with a ball pointer. Drawings were not measurement friendly making it difficult to measure according to new technologies. Today’s approach take seriously GDT and combining it with CT scans (3D scanner) a new approach is starting to grow resorting to model based definitions. Since all the information necessary for measurement is in a model when a CT scan is performed one can imideatly discover part variation and perform analysis on the intended planes with no miss communication.

A glimpse into the future of metrology

Be advised

Although I work in the area of FEA and CAE and what not, I don’t know everything, far from it. Since there are many interesting subjects to study that I don’t master, I will use this blog to divagate on my first mental analysis to starting building a model join me and give me your insight. Every single problem presents numerous learning oppportunities and I figured that this format would be great to share. Some things will be correct, others will be wrong but in the end we all benefit since there is no one wright strategy and the result is simply pure imagination set wild.