- [Instructor] Now the first step
is to open up the SolidWorks part
which is gonna be plate_2_start.
Now if you don't have access to SolidWorks 2018
or later then use the parasolid file instead.
You're going to open up the SolidWorks part.
Now the simulation tab has already been selected
so let's go down and click on the
study 10 millisecond impulse.
Now move to result options,
right mouse click Edit/Define.
We're going to pick selected modes for the results.
Now click on edit and we'll see a list
of all the modes that are available.
So deselect everything except
for mode one which is 17 hertz.
Click okay and then close down the result options.
Now the plan is to rerun the transient analysis
but only use mode one.
To do this we're going to copy the current study,
so copy study, and then we'll rename it.
We're calling it 10ms_impulse_mode_1.
Now check okay to create the copy of the study.
So let's review the result options.
Right mouse click, select Edit/Define,
and there's just an empty radio box
next to all modes because we only have one mode selected.
Check OK.
Now we run this analysis with just one mode.
I've accelerated the timeline so
we quickly get to the results.
Now we inherited this mode shape plot from the first study.
It's labeled mode one but rather confusingly
it's actually showing mode six.
Now we've also inherited the response graphs.
So let's go to the response graph called Response2,
which is our acceleration graph.
Right mouse click and another graph appears.
And we can see very clearly that this only
contains ingredients for mode one.
All the high frequency content has been filtered out.
Now I'm going to save the data in the graph
as a comma separated variable file called mode_1.
I'm going to use this to create an Excel spreadsheet
which will show all the modal contributions
to the transient.
So let's close down the graph and
then open up the displacement response to the transient.
The plot shows the displacement at
200 time steps which was .078 seconds.
Now let's animate the displacement time history.
So right mouse click select animate
and then we have the default settings.
I have a small amount of computer memory
so I can't buffer the full 667 frames.
I get warning to that effect.
So I'm going to reduce the frame rate
by a factor of five and then I'll restart the animation.
Now as we run through the transient event
we can see that the response is totally
dominated by mode one.
There are no other modal contributions as you would expect.
Now we'll run through the response one more time
and we can see there are five swings
which is what we had planned and
then there's a decaying response.
We'll stop the animation there.
Now I'm going back to the 10 millisecond impulse study
which contains all five of the modes.
So I'm going to result options,
right mouse click, Edit/Define.
And then choose selected modes.
So let's select mode two and deselect mode one.
Now I'm going to copy this study as before
and create a transient which only contains mode two.
So copy the study and we'll rename this 10ms_impulse_mode_2.
Now we run this new study.
Again I've accelerated the timeline so
we go pretty well straight to the results.
As before we go straight to the acceleration
response graph which we inherited.
So the graph only contains mode two results.
We can see that by I.
It's a higher frequency than before
and we can see the rapid decay due to damping.
As before I'm going to save the data
as a comma separated variable file.
This is going to be built into my final Excel spreadsheet.
Now I close down the graph and as before
we want to look at a displacement animation
of the transient.
I get the same warning as before
that I have too many frames so I'm
going to reduce the frame rate again by a factor of five.
Now the animation shows us very clearly
that we only got the torsional content
coming through from mode two.
Again we can sense the higher number
of swings, a higher frequency.
It's also easier to see the affect of
damping from the early time.
Displacement amplitude reducing very rapidly.
And we'll stop just there.
And once again we'll transfer to the master study
and change the selected modes we want
down to mode three this time.
And once that's complete we take another copy
of the study and this time we call it
10_millisecond_impulse_mode_3.
Now we launch the study and as before
I've sped up the timeline so that
we get straight to the results.
We pick the acceleration response graph that we inherited.
Now the graph shows very clearly
that very high frequency content coming from mode three.
The graph also shows the high frequency content
under the impulse loading.
Now as before I save off the graph data as a csv file.
Now I just the graph down and we're ready
to do another transient animation of the displacements.
Now as before the default gives
too many frames for my computer memory
so I have to reduce that by a factor of five.
Now I've paused the animation at
a very early time because we can
see the mode shape associated with mode three.
Beyond that it damps out very quickly
In fact we can barely see any response
and we'd have to scale up the
defamations fairly considerably.
Now I'll stop the animation at that point.
Now in fact I repeat the exercise for mode four
but rather than go through the whole process again
what I'm going to do is accelerate the timeline
and we'll look at the response graph
and then we'll also look at the transient.
So here is the time history graph of mode four.
We can see the very high frequency content.
But you can also see very clearly the exponential
decay due to damping.
So here is the transient animation
just with mode four content.
It damps out very quickly but we
can see the mode four shape in the
early time response just there.
And then for the rest of the transient
we can see that damping is dominating
and there's very little evidence of response.
In summary I've produced a set
of csv files each with a time history graph
of the displacement response for each mode.
In the accompanying videos you'll
find a description of the Excel spreadsheet
which I built which combines these.
I recommend you also try this workflow
and build a spreadsheet for yourself.
Now we'll save off the file and we'll
save it as SolidWorks part named as plate_2_end.
We do want to save the results and we'll finish there.