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How to apply weighted links for 2 Mass points to a tube end surface?

JS_9824412
12-Amethyst

How to apply weighted links for 2 Mass points to a tube end surface?

JS_9824412_0-1646412417999.png

In the above screenshot, there is a Pressure Relief Valve (PRV) and an Adapter installed at the end of tube (pointing downward). When I applied two Weight links (as shown in the 1sigma stress plot at the right side), the max stress is 100+ times higher than the one shown in the plot at the left side, in which only one weight link is applied. What is the problem to two links? Do I have to combine the two masses into one mass point in order to simulate both mass contribution from Adapter and PRV? 

 

Thanks.

Also, is there a good reading about "weighted link" (and "rigid link")?

1 ACCEPTED SOLUTION

Accepted Solutions
Chris3
19-Tanzanite
(To:JS_9824412)

I am assuming you have done the simple checks of double checking your masses and the units? Is this a static analysis or dynamic?

 

Are the displacements unusual as well?

 

I would suggest separating the end attachment point into 2 points that are separated slightly and see if that comes closer to the result you expect. Other things you could try - change the weighted links into springs.

 

Rigid links are RBE2 and weighted links are RBE3s. If you do a google search for RBE2 and RBE3s you will gain a better understanding of what each one does.

View solution in original post

2 REPLIES 2
Chris3
19-Tanzanite
(To:JS_9824412)

I am assuming you have done the simple checks of double checking your masses and the units? Is this a static analysis or dynamic?

 

Are the displacements unusual as well?

 

I would suggest separating the end attachment point into 2 points that are separated slightly and see if that comes closer to the result you expect. Other things you could try - change the weighted links into springs.

 

Rigid links are RBE2 and weighted links are RBE3s. If you do a google search for RBE2 and RBE3s you will gain a better understanding of what each one does.

JS_9824412
12-Amethyst
(To:Chris3)

The masses and the units are correct. This a dynamic random analysis. The two mass points are independent from each other. 

 

See below screenshot, the maximum displacement (on the right side) are around 50% less along X and Y axes, however, is similar along Z axis.

JS_9824412_1-1646664251907.png

I have combined the two masses into one mass point in order to simulate both mass contribution from Adapter and PRV, the latest simulation result looks ok now (which means the problems post is covered up, but not solved.)

 

I am to do a google search for RBE. Thanks.

 

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