Wednesday, December 18, 2013

Evolution of Engineering Simulation, 3D CAD and New Opportunities

My first 3 years in engineering school were dependent on the slide rule.  I still amazes me that we were able to do logarithms and trig functions to sufficient precision to do almost all of our calculations.  One exception was in surveying where we would have to use tables of logarithms carried out to 10 or more places.

In my senior year the handheld calculators became available and engineering changed overnight.  I paid an extra ~ $50 for my first to get the square root function.

45 years of Engineering Simulation.
My first engineering job was working for an aerospace company in Southern California in the late '70's.  I was one of 60 or so stress engineers working on some pretty high tech energy and propulsion systems.  Some our creations put many an astronaut safely into space with safe returns.  Our "simulation" or as we called them at that time "analysis" tools were mostly "classical" or "hand" calculations and Roark's Handbook was our "Bible."  We did have access to some FE tools.  We needed to fill out the 80 column Hollerith card sheets and sweet talk the basement residing keypunchers to punch the cards for us.  Our jobs would run overnight on the IBM 370 and be ready for us the next morning with 1-2 inch thick printouts to sieve through.  Many of my colleagues would build caves around their desks with their collection of these printouts.  I suppose a prelude to the present day cubicle.

Our thermal analysis brethren worked similarly as did the flow and vibration folks.

All the design work was done on drafting boards.  The high tech of the design room was the electric eraser.

Jump ahead to the mid 1980's and CAD made the scene. The CAD terminals and software were so expensive and difficult to use that the dim lit CAD room was developed with only the CAD specialists allowed to use the new stuff.  The design boards were still everywhere.  FEA had progressed a bit and shared dumb terminals were available for data entry.  The 80 column input format was still prevalent.  Post-processing was still sorting through reams of paper or viewing columns of numbers on a CRT screen.

Jump ahead to the late 1980's and the Mac and mouse were introduced.  Didn't do much for engineering yet.

Into the mid 1990's and PC's were now pretty common in the more progressive companies.  3D CAD was starting to make some headway but it was mostly limited to dedicated designers in the companies that made the move.  CFD was becoming available.

In the late 1990's 3D CAD was very common.  Many engineers were becoming proficient at using it and doing designs from scratch and then passing them off to the detailers who many times would redraw the models to create the 2D drawings.  FE and CFD now had GUI's.

By 2000 3D CAD had matured to a near commodity.  The choice was usually based on seat cost and who you thought would stay in business. Some of the early market leaders were bought up or went out of business because they could not keep up.  The Windows PC was becoming the platform of choice for desktop and engineering applications.  FE and CFD tools could start to use CAD geometry data directly.

From 2000 to now the analysis tools have evolved to include "multi-physics" with structure, thermal, flow, electro-magnetics and so on becoming more integrated with their respective interactions.  Using CAD geometry is standard procedure.  Many CAD systems have their own simulation tools built in or at least with connections to it. The job of designer (drafter) is less defined and in many companies they are phasing out or evolving to more of the design role rather than just drafters.

Where is this all headed?  I suspect in the short term there will be even more integration and further ease of use.  Many of the general purpose simulation tools will introduce more and more physics and multi-physics capability.  Users won't have to be as specialized to get results.

With these advances opportunities will also arise.  

The quality of the results will have to be checked more so than in generations past.  In the slide rule era one had to have a feel for the answer just to know where the decimal point should go.  One would have to know which text book equation was the most appropriate.  Today's tools don't require that level of intuition and it has become very easy to generate gigabits of results in milliseconds.

Many of the general purpose simulation tools try to be everything to everybody.  That's ok but with that comes the burden of layers and layers of windows and tabs for the input.  For example,  try to do a "simple" static beam simulation in one of the general purpose FE packages.  It will typically want a STEP file from a 3D CAD model for the geometry.  If that is not available the user could create a 3D model in one of the add-on GUI's or try and use a "stick" model (2D representation instead of 3D).  But then there's a  dozen or so windows to define the section properties, boundary conditions, loads, material properties, desired output, and so on.  Want to do a transient response simulation on the same beam?  Add another dozen windows to meander through for selecting the modal or direct solution, time steps, load table, etc.

If you are a "causal" user of the software you might have an answer in a few hours or even a day or two after starting. That is further dependent on whether you can even get access to the software because many of the general purpose packages are 10's of thousands of dollars to purchase and maintain and therefore most companies keep the number of seats in check.  A more experienced user might plow through this in an hour or two.  But in either case if a trade study is needed on the subject beam then many more hours might be necessary.  Macros could be written but that requires it's own expertise and usually only worthwhile if this will be a common scenario in the future.

Many of the general purpose tools are just not appropriate for some simulations.  Try modeling and optimizing a natural convection finned heat sink with several different heat source and fin scenarios.  Yes, there are CFD packages that can technically do this.  But it would typically take days to get the desired results and would usually have to be done by a CFD software specialist.

For preliminary or conceptual design studies the general purpose simulation tools and 3D CAD are not well suited and in most cases way overkill.  This part of some development projects requires quick scenario playing and dozens or more what if's quickly assessed.  The ideas that do not meet the general criteria are quickly tossed.  Trending is also often done.  General limits established.  For example,  for a thermal management application one needs to quickly decide if air cooling is sufficient and if so, does it have to be forced or will natural possibly work.

As a result specialized software modules are now starting to be introduced that make these types of studies much more efficient before the more general purpose tools are needed or even desired.