Hi, my name's John Doyle and I'm
a technical manager at Solid
Solutions. I've worked in the
CAD industry for over 25 years
and in recent times, I've
specialized in the Simulation
tools. The CAD industry actually
goes back much further than my
career, with the very first
development started by Patrick
Hanratty, known as the father of
CAD-CAM right back in 1952.
This video is showing a
demonstration of the first
interactive CAD program which
was called Sketchpad, developed
at M.I.T. in 1963.
It used a light pen and then an
oscilloscope to create and edit
geometry.
The 1970s saw the start of 3D
CAD and in 1977 the release of
CATIA which stands for
Computer-Aided Three-Dimensional
Interactive Application.
It started as an in-house
development by the aircraft
manufacturer Dassault, to
develop their Mirage fighter jet
and was later adopted by
aerospace automotive and
shipbuilding industries amongst
others.
The widespread adoption of CAD
started in the 80s with the
release of AutoCAD in 1982.
However this was still primarily
2D, and it wasn't until the
release of Pro Engineer in 1987
that Saw 3D become available to
a wider audience.
In the 90s, PC's finally became
powerful enough to run 3D CAD
applications and in 1995
SOLIDWORKS was released which
was the catalyst for the
mainstream adoption of 3D CAD.
Today,
Virtually every product thats
manufactured will have been
created in 3D CAD.
There are free online packages,
it's taught in secondary
schools. For example, every
secondary school in Ireland
teaches children SOLIDWORKS
there is even software aimed at
primary school-aged kids.
So 3D CAD has undoubtedly made
it to the mainstream. But can we
say the same for virtual testing
or simulation software?
Despite the fact that the
development of FEA running on
computers also dates back to the
60s, it has not yet become as
widespread as 3D CAD.
So what are the possible reasons
why this is the case?
Is it cost? Ease of use? A lack
of integration with existing
design tools? Or the perception
that there's a need to employ an
expert? In this video,
We'll look at how SOLIDWORKS
Simulation solutions can address
some of these concerns and
hopefully try to demystify
simulation.
The simulation products cover a
range of different disciplines
from structural simulation which
typically looks at stresses and
displacements in parts and
assemblies under a range of
different conditions
Fluid Dynamics which looks at
how models interact with liquids
and gases, plastics to simulate
the injection moulding process
and motion which looks at the
physics of moving assemblies. In
this video,
we're going to concentrate on
the two most common areas of
Structural Simulation and Fluid
Dynamics. All of these tools
share the same core values in
that they're easy to use and
integrated within the design
process.
They're also able to work with
each other, so we might use flow
to calculate pressures or motion
to calculate forces which are
then applied as loads in a
structural simulation. Within
structural,
We have a wide range of
different study types. Our loads
can be static or dynamic,
The material behaviour can be
assumed to be linear like metal
or nonlinear light rubber,
we can also look at resonant
vibration drop tests and many
other scenarios. We can then
optimize designs either through
changing dimensions or changing
the shape. We have customers
using these tools
in all industry sectors, from
heavy industrial applications,
through to consumer goods. One
of these customers is Renthal,
who are a global leader in the
design and manufacture of
components for motorbikes,
cycles and all-terrain vehicles.
They started manufacturing
handlebars for motorbikes 50
years ago and more recently in
2010 expanded into cycling
products.
Their components are now used at
the very top of World Sport,
With over 200 motorsport world
titles and 11 already in
cycling. All bikes and their
components have to comply with
the ISO standard 4210, which
stipulates the test that parts
must pass. One such test that
rental needed to simulate was
the fatigue testing of
handlebars and stems, as shown
in this video. Being able to
virtually simulate this test not
only alleviates the time and
costs involved in machining
prototypes but also means they
can produce a better design that
stiffer and lighter with
confidence that it would pass
the test first time.
In this example, we're going to
replicate those tests using a
BMX bike stem. The standard has
different categories for
different types of bikes, so
we'll use the highest load for
BMX. But it's still quite
conservative, so we'll double
the number of cycles and
increase the loads by 50
percent.
The test has two different
elements. In phase loading,
where both sides are forced up
and down together or anti-phase,
where one is forced down and the
other up.
These are run as 200,000 cycles
of each. We typically start with
a static study and as we're only
interested in the STEM, we have
replaced the handlebars with a
test bar. Directly inside of the
design environment, we can
create our simulation study,
which presents us with a list of
items to consider. First, we
have the material which has
already been applied.
Then we have the interaction
between the various components
which we'll change from being
bonded to allow the parts to
slide and separate from each
other. As we aren't including
the steerer tube,
we'll simply fix the back of the
stem.
We then apply our loads and
we'll start with the in-phase
test with two forces acting in
the same direction.
Finally, we can include the
effect of the bolts including a
preload as a torque
and then we simply mesh and
solve our study. The default
result
plots are exaggerated to clearly
show how the parts reflect,
which we can change if desired.
The initial results show us the
stresses in the various parts.
To understand the implications
of those stresses.
We can look at the factor of
safety and by giving the areas
that are carrying less load a
different colour,
it gives us some insight into
the material we could safely
remove if we wanted to make the
part lighter, without impacting
the strength.
As we're always in SOLIDWORKS,
we can make quick changes and
see how the factor of safety is
affected. Because we've removed
geometry that wasn't
contributing to the strength,
we can quickly reduce the weight
without compromising the
stiffness. Having finalized our
design, we will now move on to
the fatigue test. With the
inclusion of the bolts which are
a dead load, so not loosened and
tightened with every cycle, we
need to start with all four
cases. Up, down, clockwise and
anti-clockwise. In the fatigue
study, we can then alternate
between two of these studies for
each test, applying two hundred
thousand cycles of each. The
results then show us how much
damage these cycles will have
caused.
The values represent a
percentage of the life that the
tests have consumed. In this
case, 3% shows that our design
would easily survive those
400000 cycles and if we
continued for many more, where
the cracks are likely to
develop. That has shown how
Simulation can help validate and
also guide the design of an
existing component but it can
also create brand new geometry
through topological
optimization. Here,
we're trying to create a brand
new design for a mountain bike
stem. Was built in some basic
parameters such as an 18
millimeter reach in a 6 degree
rise along with locations for
clamping around the tube and
bars.
Other than that, we've just
modelled a maximum space
envelope.
We can then apply all four load
cases from the previous example.
We want to produce a shape with
the maximum stiffness to weight
ratio and can also include some
constraints such as Symmetry and
retaining some geometry around
the clamps.
The results can be quite
striking and very different from
conventional designs.
We can smooth this result, and
potentially create a part
directly using additive
manufacturing or use it as a
graphical guide to create a
brand new optimal design.
We'll now move on to SOLIDWORKS
Flow Simulation, which is a
general-purpose fluid dynamics
application that can solve the
majority of fluid-related
problems.
There can be internal like fluid
flowing through a flow control
device or external like drag on
a vehicle or convection from a
hot surface.
It covers all modes of heat
transfer,
we can simulate how fluids mix
or more complex problems like
rotating geometry, free surfaces
like water filling or sloshing
in a tank or highly viscous
liquids like blood or oil. Flow
Simulation is again used in a
wide variety of industries,
one of the fastest-growing areas
is in electronics. As devices
become more powerful, and at the
same time smaller,
The challenge of keeping them
cool is increasingly difficult.
One example is Naim Audio,
the British hi-fi manufacturer.
They were founded in 1973 by
Julian Vereker a racing driver,
entrepreneur and self-taught
engineer. Dissatisfied with the
quality of his home audio
system,
he decided to build his own.
Naim have since gone on to win
numerous Queen's awards and have
built a reputation for quality.
In 2014, they launched their
groundbreaking statement
amplifier. Using fans to keep
electronics cool can have a
detrimental impact on sound
quality, so they use flow
simulation to ensure that the
electronics could be kept cool
without using the fans in all
but the most extreme conditions.
Due to the costly components,
building prototypes was very
expensive and time-consuming so
flow simulation was able to
ensure that they got the design
right the first time.
We'll use this small electronics
device to look at how we can use
flow simulation to predict and
visualize the fluid and thermal
behaviour inside this assembly.
We'll look at having funds
inside the box or directly
mounted to the case and whether
we can improve the performance
of the heat sink.
Again, all of the setup is done
inside SOLIDWORKS.
We start by defining the air
inlets. If there are slots or
hole patterns on the vent you
can easily account for these
without the need for the
geometric complexity, reducing
computation time.
You just need to specify a
couple of parameters for the
whole pattern.
The fans can be specified from a
large built-in commercial
library or specified manually.
Heat sources for the electronics
components are specified. Flow
also includes the ability to
accurately model semiconductor
heat transfer such as for this
CPU. it provides a wide range of
visualization tools to gain
insight into the fluid behaviour
inside the model. Section plots
allow you to look at a
cross-section of the model at
any location and select for a
wide range of characteristics
such as velocity, pressure or
temperature. The Surface plot on
the heat sink
provides a clear view of the
temperature distribution, making
it easy to identify un-even
calling and potential hotspots.
ISO surfaces are used to show
the results of the same
magnitude in the design, such as
air temperature. You can also
show numerous values at the same
time and by making them
transparent,
it's a great way of visualizing
the flow behaviour in 3D
throughout the whole model.
Flow trajectories are another
great way of visualizing the
flow in 3D. Allowing you to see
far more than you would in any
real experiment with the ability
to animate results and interact
with the model,
you gain great understanding of
product performance. It's
sometimes difficult to
understand how heat moves around
in an assembly. The heat flux
plot can show us what is
happening visually, we can look
at the whole model or just
select certain parts.
In this case, the main CPU. We
can see that a tiny amount of
the heat is convected directly,
2.7 Watts goes into the PCB and
the majority goes through the
heat sink and out into the air.
The compare tool will allow us
to easily compare the different
design concepts and select the
best option to move forward
with.
You can select from both
graphical and numerical results,
which we can then compare side
by side.
It then loads each result that
captures the desired information
and collects it into images and
tables for quick and easy
review. Switching to the
external fans configuration, we
can see that the recirculation
has been eliminated and
temperatures have dropped. If we
needed to further reduce the
temperature on the main chip, we
could look at improving the
performance of the heating sink.
And just like Structural
Simulation, Flow can also drive
the geometry through parametric
optimization.
We've taken the chip and heat
sink in isolation to speed up
the calculations. Using the
design of experiments tool, we
can specify a number of
parameters to vary.
Here we've chosen the number and
thickness of the fins. Select
the goal we want to optimize, in
this case minimizing the
temperature of the chip and then
simply specify the number of
experiments we'd like to run.
From those results, Flow
Simulation can predict what the
optimal values would be.
We can also visualize the
results on a 3D surface as we
might be able to identify an
alternative result that's nearly
as good, but cheaper to
manufacture. Conventional
thinking would suggest we just
need to maximize the surface
area.
But if we make the channels too
narrow, the flow velocity is
reducing preventing the heat
from being moved. This plot
shows us where the sweet spots
are with the best compromise
between those parameters.
We've seen how we can solve a
wide range of relatively complex
problems simply inside of the
SOLIDWORKS environment, But
occasionally there are
challenges that go beyond it's
capabilities.
In those circumstances, we now
have a solution that allows us
to use the most capable
simulation tool available
directly from withinside
SOLIDWORKS and crucially
maintain links to the CAD
geometry,
should it change.
It's called simulation
professional engineer and is
built on SIMULIA, an incredibly
powerful robust and fast
simulation solver. In this
example,
We want to study a very large
compression of a complex
nonlinear material. We can do
our set up in SOLIDWORKS and
then transfer the geometry and
boundary conditions directly to
SIMULIA.
We have access to more material
models, here we will choose a
hyper foam. We could use the
mesh from SOLIDWORKS but we
might have more success with a
different type of element. So,
we'll swap the foam and plate to
a hex mesh. With those changes
quickly made,
We can now run the simulation.
We can choose to run it locally
but also have access to more
computing power in the cloud.
If we need faster results very
quickly SIMULIA is able to
complete the compression of this
foam. If we were to change the
geometry back in SOLIDWORKS, we
could directly update the
geometry and just rerun the
simulation.
In conclusion, we've seen how
SOLIDWORKS Simulation tools can
solve a wide range of design
problems. Being integrated in
the design environment makes it
familiar and easy to use and
provides insight into the
implications of design changes
or alternatively, drive the
design through optimization.
We then saw that if we have
extremely complex problems that
exceed the capabilities of
SOLIDWORKS Simulation, that we
still have an integrated and
easy to use alternative. I hope
that demonstrated that
simulation tools can become an
integrated part of the design
process as we move towards a
wider adoption and have helped
to demystify simulation.