Vespa in the hood

We see every day things that have really great designs, other which are terrible for our taste, others memorable in any time and age that are transversal to age, gender, location, …. Good old designs that were imagined with pencils and paper.

I still keep wondering how would those brains design with today’s tools??? How would they reimagine things with CAD (Computer Aided Design), CAE (Computer Aided Engineering), and CAM (Computer Aided Manufacturing).

Vespa In The Hood
Vespa In The Hood

The bridge builder game effect

Going back in time, I just remembered about a game that gave me quite a good understanding of stress distribution. Bridge builder. Using simple truss combinations to allow passage of vehicles through it. Some times the most chalenging designs required the use of circular shapes to transfer stress from one point to another, distributing it through as many bars as possible…

Bridge Builder
Bridge Builder

This sun lounger supporting legs are made of a single component and has one main function, to support the weight of the occupier and a bonus function to support the arms. Stresses are evenly distributed throughout the structure and the design feels more organic.

Stress Distribution
Stress Distribution

 

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

 

Light pulls us in

One has to go to feel, I always say. I could have never imaged time square and the feeling it was to actually be there. I felt so small in the middle of so many people going up and down and bellow so many huge buildings. But to top it all is to be in time square at night, those billboards were everywhere and so filled with light. I spend numerous hours trying to model reality, but sometimes I think I am in some kind of virtual reality environment.

Time Square Buildings
Time Square Buildings

 

 

The Brompton Handlebar Case

I started my week looking at my Brompton bike handle bar and noticing that a friends bike had a different one. Same model type but with a different design shape.

Brompton handlebar
Brompton handlebar

My Brompton version is a 2017 model however my friends model is a 2015 model.

2015 Brompton handlebar
2015 Brompton handlebar

Notice the length of the central U shape arms. Smaller?

2017 Brompton handlebar
2017 Brompton handlebar

In my bike version there was a reduction of the length of the straight tube and the two bending zones are pretty near .

I have to mention that this  changes a bit how the Trigo Brompton bike acessory fits. Why? On the first design (2015 version) the accessory at the bike folded state will be positioned much higher far away from the wheel axel giving space. In my version it gets aligned/touches making my life just a bit more difficult to fold the bike with the go pro attached.

I am wondering why they made the change. Was it due to reduced stiffness? Cracking of the handlebar?

I really liked the biking handling the new handlebar offers it feels great and allows me lean a bit when curving.

 

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

Gondole Gondola

Gondole, gondola… The infernal traffic on the Venetian channels.

Today I woke up with a melody on my head…. Gondole, gondola, … gondola, gondola.

This was the way the gondolier called clients in the middle of a Venetian Road to take a stroll on those beautiful venetian channels! As I responded affirmative to his call, I followed him to take this so typical gondola ride along the canals… and there I was in the middle of so many gondolas, stuck in traffic (can you imagine).

I have never imagined that in such a small space could fit so many gondolas. Hope to one day return to once again take a ride on the heavy traffic canals of Venezia.

Gondole Gondola
Gondole Gondola

The moon & maybe some optics

I had the magnificent privilege to stare at the moon on a deeply dark night. I went initially to see the milky way since the observatory is located on a Dark Sky reserve. A Dark Sky reserve is a an area which guaranties low illumination at nigh allowing for high quality star gazing at night. Unfortunately the Moon out shined many starts and reduced star gazing conditions. Although I did’t have great conditions the moon was positioned just right for some good Moon photos.

I normally focus my attention to more standard questions “will the bridge withstand the train?” or “what is the temperature in my room if i turn on the heater” or even “will this shape have good aerodynamics?”. But do we often ask our serves “will light reflect?”, “How does light reflect?”. (Maybe optics specialists look at this) Simulating light. I know this subject isn’t new. What is this nowadays? Still this affects our glasses, telescopes, data connections through finer optics.

Since I know little about this subject, I will investigate deeper what is out there regarding simulating light.

The Moon
The Moon at a Dark Sky reserve taken from a telescope in combination with an iPhone..

An illustration of the FEM study process

Good comercial packages integrate conveniently all steps required to get results with minimum effort. As I have been demonstrating on previous posts, since open source softwares grew up each in their single box, with specific intents at their time, integration never was a primary concern, however as they matured, naturally, synergies start to take place and each project starts to fit together to supply the integrated platform that everyone is urging for. 2017 will be a year that will bring two interesting versions os software that integrate it all, FreeCAD 0.17 and Salome-Meca 2017.

Simulation Process Steps
Simulation Process Steps

Calculix interoperability

I talked a lot about Pre processors FreeCAD and Salome, in some cases the pre processor environment is more and offers the complete modelling package including a solver as in the case of FreeCAD. Calculix is the tool that will pick up a meshed model with boundary conditions and calculate specific results, being structural displacements, stresses, thermal behaviours and other physics.

A good work that was performed in making sense of these tools can be found on the following link:

https://www.theseus.fi/bitstream/handle/10024/87106/Neupane_Dilip.pdf?sequence=1

and Calculix documentation can be found here:

http://web.mit.edu/calculix_v2.7/CalculiX/cgx_2.7/doc/cgx/node4.html

It is important to know what Calculix needs input files  calculate something, this will depend on the type of files.

Geometry
• .Fbd
• .Step
• .stl

Mesh Generator and boundary-condition inputs (Model)

• Abaqus (Input)
• Ansys (Export)
• Code_Aster (Export)
• Samcef (Export)
• Dolfyn (Export)
• Duns (Export)
• Isaac (Export)
• OpenFOAM (Export)
• Nastran (Export)
• Tochnog (Export)

Mesh Generator

• Abaqus (.inp)
• Netgen

Read solver files
• Frd
• Duns
• Isaac
• OpenFOAM
• Nastran