Typo Corrections to:
DDM for SW Training January 2001.ppt
notes)
(corrections to text on the slide and text in the speaker
Slide 4
Override mass properties and define initial conditions for parts? Can you expand on this?
(Ans. 9/4/1 I noticed in SolidWorks 2001 you can rotate parts around axes to a specific angle.) But the
mass properties are confusing. DDM gets confused about mass properties of configurations.
Slide 5
Update with 3D contact?
Slide 13
How is Inline different than Cylindrical or Translational?
Slide 17
"three moving link (yellow)" should be "three moving link (blue)"
and "two grounded parts (blue)" should be "two grounded parts (yellow)"
and "part Ground" should be "part Ground-1" and "driving
Link" should be "driving Link-1" and "driving torque of Ground" should be
"driving torque of Ground-1"
Slide 19
The notes say to "ensure gravity is in the -Y direction". Show how to determine
that's what it should be. Go over:
View -> Origins shows origins (grey) for each part and for the assembly, but doesn't
label the axes.
Tools->Measure shows the assembly origin with labeled coordinate
system (green)
Tools->Mass Properties shows the assembly origin with labeled coordinate
system (green) along with a coordinate system for the principal axes of inertia
labeled Ix, Iy, Iz (red)
Slide 25
"part Ground" should be "part Ground-1" and "driving Link" should be
"driving Link-1" and "driving torque of Ground" should be "driving torque
of Ground-1"
Slide 23
"between LINK and GROUND" should be "between Link-1 and Ground-1"
Slide 25
"Link, Link2 and Link3" should be "Link-1, Link2-1 and Link3-1" and "move
Ground and Ground2" should be "move Ground-1 and Ground2-1"
Slide 27
on the slide, "Between Ground and Link" should be "Between Ground-1 and Link-1"
Slide 29
Slide 27 said that Revolute2 was the joint that was going to be driven (between
Ground-1 and Link-1). Yet Slide 29 shows a menu under Revolute3 having a Rotary
Motion Generator option, which can't be. So the resulting graph makes no sense.
The graph of the angular velocity of Link2-1 doesn't make much sense to me. Why does
the angular velocity of Link2-1 about the z-axis start out negative? Can you define what is
meant by angular velocity more precisely? what with respect to which coordinate system?
Also, for the angular velocity of Link2-1, my graph comes up with a different title, "Angular Vel -ZLink2-1", whereas the slide
has it as "Angular Vel -Z-Link2.par:1"
Slide 30
"after and entity" should be "after an entity"
Slide 38
What's a JPrim? What is an Inline constraint? What is in line with what in this joint?
Slide 48
This is important and should be expanded upon. Show some examples and describe exactly
what the plots are showing.
Slide 49
Check the assembly coordinate system to see if gravity is defined correctly. Do Tools->Measure
to see that the assembly origin's xy plane is along the top of the base and the positive z-axis is
towards the sky. Gravity needs to be set to the -Z direction.
SCISSOR LIFT
Slide 50
The phase shift is 90 degrees because we want the displacement to begin at 0mm. (?) From
Slide 44, it looks as though for zero displacement, you want the phase shift to be zero.
How do you know that displacement is along the z-axis? The z-axis of which part, the piston
or the cylinder? Or does the joint have a coordinate system of its own where the "z" axis is
defined as the axis of translation for a concentric joint? (I'm guessing the latter.)
Describe how to see which direction on the joint is defined as the positive z-direction. Zoom
in on the piston-cylinder joint, Concentric12. Click right on Motion Model and select Display
Parameters. Select the Display tab. Select Visibility On, Click on Assign to All Types and
Apply to Existing Entities. You can see a large green arrow defining the joint's positive z-axis.
That arrow goes away if the Concentric12 joint's motion is deleted and it is set back to Free.
The resulting Translation Motion Generator Force Z for Concentric12 doesn't make much
sense. Why is it always negative? (The result is different that in the slide, since gravity was
defined wrong in the slide's results.)
Slide 54
The notes say:
"Positive force is tension (points being pulled towards each other). Negative force is
compression (points being pushed away from each other)" which is backwards.
DOOR
Slide 59
There’s no way to see the assembly origin or how the global assembly coordinate
system is set up. I tried Tools->Measure, Tools->Mass Properties and View->Origins,
but there’s nothing there.
Slide 65
The translational velocity output goes to zero, but the door doesn’t close (it hangs open)
so the problem hasn’t been solved. From this model, how would you interrogate the model
to figure out what the door-closed criteria should be?
Slide 66
“over 4 seconds” should be “after 4 seconds”
Slide 67
The assembly has a part called volume-1 that isn’t put into either Moving parts or Ground parts. If you
select it, nothing highlights. What is it and what is it for?
GOVERNOR
Slide 70
How do you know the zero position of the Concentric joint? (i.e. where is displacement measured
from?)
Slide 80
The notes say velocity should be –360 deg/sec, but the slide says +360 deg/s. The results plots on the
slides match for –360 deg/sec.
ELECTROMECHANICAL SWITCH
Slide 85
The plot in the slides for Translation X Velocity of the contact button, doesn’t match the results that I
get. I don’t get the nice overshoot and ring down.
The notes suggest looking at the Rotary Motion Generator output. I have a question about that in terms
of comparing the Moment Z to the Magnitude. Why does the Moment Z graph go negative?
Slide 89
My results didn’t go as high as 74,000 N. Roughly 70,000 N.
Slide 93
The graphic in the slide is wrong. The arrow extending from the dialog box “Body-1/DDMFace10” is
pointing to the wrong face. Face10 is the front of the rail car, not the side. Also, the other dialog box entry
is wrong. The arrow extending from “Body-1/DDMEdge1” is pointing to the correct edge, but the edge’s
name is “Body-1/DDMEdge2”.
Slide 95
I don’t understand what the projection angle is…???
Slide 97
“selects” should be “selected”
Slide 105
When I select the camshaft face, I don’t get what the dialog box on the slide says (it lists 3 edges). I get
Camshaft-1/DDMFace20
Slide 107
The contact tab dialog boxes no longer look like that.
Slide 108
There are some random empty boxes on the slide when you print it out.
Slide 110
My results don’t look exactly like the graphs on the slide (the rocker doesn’t come back and hit the
came)
FORKLIFT
Slide 113
Why is the Translational Z final position at –1800 mm? The joint arrow is pointed towards the sky
and the initial position (at least the way the model is upon opening) is with the fork at the position closest to
the ground. Or is the initial position somewhere other than where it is when you open the model?
Slide 115
Why is it necessary to add a planar joint?
Slide 118
Why are the results the way they are? What are they really representing?
Slide 121
Why is it necessary to delete the distance constraint (what was it there for in the first place) and why
was it necessary to add a planar constraint?
Slide 122
The dialog box doesn’t look that way any more. And if I change the density to 1e-7 (0.0001g/mm^3) in
the Motion Browser, the total mass of Wheels-2 does decrease by an order of magnitude to 34 kg.
However, if I keep Wheels-2 selected and choose Tools->Mass Properties, the Mass Properities dialog box
pops up with Items Selected as Wheels-2@Forklift_Driving_Anita. However, in the output text box for that
dialog box (which is titled “Mass Properties for Wheels-2”), it says the density is still 0.001 g/mm^3 and
the mass is 345 kg.
Slide 130
“to represent and attached” should be “to represent an attached”
Slide 134
“indicated” should be “indicating”
EXCAVATOR
Slide 161
What is dummy-2?
Slide 162
The slide doesn’t match the software model. SwingTower-1 contains Revolute10, Revolute8 and
Revolute9, whereas the slide says Revolute, Revolute12, Revolute9
Slide 163
The note suggests trying the cumulative functions out in Excel. Can you expand on that? How do you
test a sum of STEP functions in Excel?
Slide 164
It doesn’t say what the extended boom is connected to at the joint in question, it just lists Revolute8 on
the slide, but since the model doesn’t match the slide, there is no Revolute8 under Extended Boom. The
joint looks to be between boom and extended-boom, which is Revolute5.
Slide 165
It doesn’t say what the Backhoe Bucket is connected to at the joint in question, it just lists
Concentric20 on the slide. The joint looks to be between Backhoe Bucket and Extended Boom.
Slide 166
The slide said to rename Revolute5 to Bucket. It should be that Concentric20 gets renamed to Bucket.
CONVEYOR
Slide 176
I’m not sure what it means to plot the magnitude of the velocity of a force (?).
ACTUATOR CLAMP & CATAPULT
Slide 187
“Actuator_Clamp_Overconstrained.asm” should be “Actuator_Clamp_Overconstrained.sldasm”
When I open the model, the picture of it is there, but then if I click on anything, it goes away. If I select a
part in the Feature Manager window and ask to open the part, I get an error dialog box that says it can’t
open the part, it’s a future version. (I’m using SolidWorks 2000.)
….9/5/1 I’m running SolidWorks
2001 now and I can run both just fine.
Slide 205
It would be good to have some slides on the catapult without results, so show torsional springs and how
the contact conditions and impact conditions are set up. It goes straight to results and exporting to FEA
without explaining the catapult itself.
EXPORT RESULTS
Slide 194
“renamed and delete” should be “renamed and deleted”
“bottom window give” should be “bottom window gives”
“the number of curve” should be “the number of curves”
Slide 195
“you must move to the model to the desired” should be “you must move the model to the desired”
Typo corrections to:
Design Analysis Based on Motion Loads Using COSMOS/Works 4.0 and Dynamic Designer/Motion
in SolidWorks Environment
p.5-19
after “select Displacement” should be a direction to select the Harmonic category in the drop-down box
p. 6-19
the dialog box doesn’t look like that. The harmonic selection also has a box for Phase Shift (in addition
to Time Offset)
p. 10-19
the menu isn’t called FEM, it’s called COSMOS/Works
p.11-19
Frame-15 should be Frame-16
p. 16-19
Frame-15 should be Frame-16
p. 18-19
Frame-15 should be Frame-16 (8 times). Also, there is no Materials folder. It’s name is Solids.
Dragging it to Frame-16 Modified didn’t have the correct effect. Had to go in manually and change the
material to carbon steel. The diagram of the Visualizer Tree is wrong, in that link_arm under Frame-15
(should be Frame-16) was renamed to link_arm, CS.