topic Re: Simulation of a lifting CE in Analysis

Simulation of a lifting CE

DenisJaunin — Mon, 16 Apr 2018 18:03:45 GMT

Hello,
To calculate a hoist as in the attached image, how do you define the crane attachment point at the top and the motor attachment point at the bottom.
In Simulate you can not leave two parts free.
Blocking for example the point of the crane will give a false representation of the deformation.
Cordially.
Denis.

Re: Simulation of a lifting CE

SweetPeasHub — Mon, 16 Apr 2018 19:22:22 GMT

Simulate can leave two parts free. (some degrees of freedom (d.o.f.) free)

IF you have applied all loads from a Free Body Diagram (FBD) and determinate Static case.

This means you are in static equilibrium.

Then turn on inertia relief check box at static Analysis Definition. (this resolves any numerical rounding errors that make the part move and not be static)

Probably best load type is BEARING Load. for hoist pin and mass pin (motor)

Another way may be cut in half and use planar symmetry since the hoist rig appears symmetric from top to bottom. Again inertia relief.

Another way instead of inertia relief for any case is to hold some area where stress is insignificant in the missing DOF. If FBD and loads are accurate then the stress will not be very much. There is a specific technique from PTC on constraining parts in static equilibrium. I could not find it in their knowledge base so it is attached here.

I found a related article at PTC support.

Article - CS59477

And here is the static equilibrium technique. It was redone for a thermal study but it is the same method.

Suggested Technique for Modeling Free Thermal Expansion

http://support.ptc.com/cs/cs_25/howto/mst728/mst728.htm#_ga=2.258133832.398535393.1523881733-1278185974.1478613588

Re: Simulation of a lifting CE

DenisJaunin — Tue, 17 Apr 2018 16:49:58 GMT

Hello,
Thank you for these explanations.
I will try to apply them.
Cordially.
Denis

Re: Simulation of a lifting CE

skunks — Thu, 26 Apr 2018 13:31:27 GMT

Re: Simulation of a lifting CE

DenisJaunin — Thu, 26 Apr 2018 17:46:05 GMT

Hello,
Thank you for your model.
But in the case of my Cé, the fixation is in a circle, how can I put points there to fix the degrees of freedom as on your bridge?
Cordially.
Denis.

Re: Simulation of a lifting CE

SweetPeasHub — Thu, 26 Apr 2018 20:20:29 GMT

maybe this?

Re: Simulation of a lifting CE

skunks — Fri, 27 Apr 2018 07:06:52 GMT

Hello Denis,

I recommend rigid links.

Re: Simulation of a lifting CE

skunks — Fri, 27 Apr 2018 08:07:50 GMT

Hello Denis,

better example test_d_new.zip

Re: Simulation of a lifting CE

skunks — Fri, 27 Apr 2018 12:31:26 GMT

Unable to play video. Please try again later.

(view in My Videos)

Re: Simulation of a lifting CE

DenisJaunin — Sat, 28 Apr 2018 17:24:14 GMT

Hello,
I thank you for your very detailed explanations and your models.
On the other hand I did not understand the utility of the spring in the model test_d_new.
(Can not read the video)
Cordially.
Denis

Re: Simulation of a lifting CE

skunks — Mon, 30 Apr 2018 05:49:34 GMT

Re: Simulation of a lifting CE

skunks — Mon, 30 Apr 2018 05:52:09 GMT

Re: Simulation of a lifting CE

skunks — Mon, 30 Apr 2018 11:58:08 GMT

fe_lifter.prt vs. fe_lifter_.prt

Re: Simulation of a lifting CE

DenisJaunin — Mon, 30 Apr 2018 13:52:16 GMT

Hello Skunks.
Magnificent.
Thank you for these explanations.
I will look at all your explanations.
Cordially.
Denis

Re: Simulation of a lifting CE

DenisJaunin — Wed, 02 May 2018 15:41:18 GMT

Good morning,
I put a force measurement on the spring by choosing spring.
But for simulation the measurement does not appear in User defined?
Sincerely.
Denis

Re: Simulation of a lifting CE

skunks — Thu, 03 May 2018 05:57:07 GMT

Re: Simulation of a lifting CE

skunks — Fri, 04 May 2018 06:15:13 GMT

Re: Simulation of a lifting CE

DenisJaunin — Fri, 04 May 2018 15:35:33 GMT

Thank you for your answer, which was always very detailed and colourful.
I'll go study the solution.
Sincerely.

Re: Simulation of a lifting CE

DenisJaunin — Fri, 04 May 2018 17:45:25 GMT

Now it's my fault, I didn't orient the axes correctly for the spring.
That's why it didn't appear in Measure.
To have the Measurements in the calculations it is not necessary to use the Measure function to load them?.
It seems to me that the Measurements are taken automatically in the calculations?.

Re: Simulation of a lifting CE

skunks — Tue, 08 May 2018 14:18:47 GMT