MSC Nastran; Patran Tutorial - Complex Modes; Direct Method Video Lecture

in this video I'll be finding the
complex modes using a direct method of
the system first start a new patron
session the units are used for this
example are inches pounds and for my
mass I'll be using pounds second squared
per inch created my new patch on file
I'll call it problem 26 click OK here
I'll start by making my nodes so here in
the meshing tab click Edit I'll start
typing in nodes so at the bottom start
with zero zero zero three zero zero six
five zero zero five zero three five zero
six zero zero after your close eye last
one hit enter or hit apply and just to
show you the notes I'll turn on the
marker here called node size now it's
time to meet the elements so go back to
the meshing tab click element edit the
shape is bar will go from here to here
here to here and so on
now I'll go ahead and create a new group
called point elements leave me current
checked so that anything I create will
be added to this group so then hit apply
so when I come here and create a new
element by hitting element edit force
all council out of this group tab you
see that the action is create object is
element and method is that it my shape
should be a point and for node one
I will make one point element here
another one here here and so on I'm
going to turn on the model tree and
under groups you'll see two things if I
turn out point elements and you'll see
that the point elements are gone and let
me turn off the node size if I turn the
group on again it'll show me the point
elements and I did this for convenience
thing so we aren't struggling later on
we'll go ahead and define our material
by going to the properties having
selecting isotropic here the material is
matte under input properties give it a
ends modulus of three e9 psi and Poisson
ratio point three click OK and hit apply
we'll go ahead and apply this material
to the the beams I'll so here under when
do properties select being call this
property beam prop under input
properties give it a material name or
select a material we just created give
it a bar orientation of one and the X
here on the y and z the area here will
be 0.79 or inertia one one would be
point zero four nine and point zero four
nine for inertia two to click OK for
application region select elements one
two three so that would be first you
would select beam elements so I can
actually select these three elements
click Add ok and apply now it's a
definer Springs under windy properties
click the spring icon call this spring
prop under input properties give it a
spring constant of five hundred degree
of freedom would be u X for node 1 into
for application region select element
four and five here at the bottom add it
ok and apply let me hide this default
group so I just have this group visible
with its point elements here I must
first to find 0 D properties mass close
this tab you'll notice your increase
your OD mass call this mass prop for my
input property so I'll give this a mass
of let me cancel this let me make this a
lump the one on your info properties my
mass would be point zero one
click ok for your application region you
will select the bottom elements here and
right now I have a point selected it
should be point element so then I am
able to drag a window and select these
six or three elements at it ok and apply
now it's time to create a grounded
damper here under 0 D properties of for
the grounded damper icon call this
damper prop under input properties give
it a damping coefficient of 20 and click
OK or actually go back there this damper
is about the z direction so I make sure
this is our Z click OK the application
region this will be applied to element 9
just this top left one added ok check
all this damper prop 9 and apply make a
new one called damper prop 10 for input
properties give this a value of 60 hit
OK for application region you'll select
this damper or element n add it to the
application region click OK and hit
apply your next one is a damper prop l11
your next one is damper prop 11 for
input properties type in 120 our Z as
usual for click OK for your application
region select this one add it ok and
apply we define the properties and now
we're moving on to the boundary
conditions I'll make one displacement
constraint I'll call it TZ because here
what we're doing is constraining just
the Z direction so that's why the 0 is
here and the
place click ok select application region
we're working with the mesh so just
select this FEM pick all the nodes and
right now I just click pickle and it's
not working the reason is because the
group but all the nodes is not currently
visible once I make that visible and
close this tab I can pick all the nodes
click Add ok and apply next I'm going to
find a new one here I'll call this one 1
2 4 & 5 the reason it's called 1 2 4 & 5
is because I'm fixing the one direction
the two the 4 the 5 and not the 6 and
not the 3 either and that's why these
two are blank hit OK for our application
region will apply this to nodes 1 2 & 3
and that would be the top ones or
actually these are nodes 3 4 5 & 6 or 3
4 & 5 added okay and apply our models
defined now I can go ahead and run this
so go to analysis analyze the entire
model under solution type
select complex eigenvalue select direct
and click OK
next we can hit apply them on this job
click xD beat import the results and hit
apply under results
let me first hide the model tree under
results
here I can see all the values now can
start comparing here the first mode is a
really small value so is the second one
the third and fourth one have a value of
27 and 55 Hertz here I have the first
and second mode followed by the third
and fourth mode and here they visually
show you so I'll go ahead and do that so
selecting mode one select a French
result if I just select that you don't
notice just a color what I can do is
increase the thickness of the line it
apply going back to select results I
have I can back your translation on for
the deformation result so then this
moves and then going on to mode 2 mode 3
and mode 4 and you'll see this as a line
with what they get here make sure you
save this and this concludes this
example