How to stiffen hook/hookgroup ties?

AIN_002

Crawler crane specialist
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I've run into a little issue...

I'm using hookgroups to attach the counterweight onto a crane. The issue is that the "ties" that the hooks create to attach&pull the object (counterweight in this case) get stretched out by the weight of the object, resulting in a non-perfect fit and that the weight keeps bouncing around a bit, which doesn't look good but also compromises the smoothness of the crane operation. See the screenshot, the visible ties should be zero length to create a perfect connection, but evidently they aren't. The hooks in question are set to shortlimit: 0.0 and a very high maxforce in order to not cancel the retraction due to the heavy load, but this is still the result. I tried to apply a set_beam_defaults before the hooks section but it doesn't seem to have any effect on the hook ties.

I also tried to do without the whole hookgroup&lockgroup feature, and only just use normal hooks (as defined by "h" after the nodes) to see if this problem was specific to hookgroups, but found the most simple hooking feature to have the same problem, so no luck there.

Any suggestions?
 

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AIN_002

AIN_002

Crawler crane specialist
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Only thing I can suggest is more hooks to compensate for the weight.
I actually tried to duplicate the hookgroup entries to see if having several duplicate hook ties in the same place would work, but with no success (no stiffness improvement). I guess I'll just have to extend the attachment system to lock onto more nodes of the counterweight N/B.

@Austin as a future development idea, making it possible to apply set_beam_defaults to the hookgroup ties would be awesome, since tight connections are vital for heavy machinery. :)
 

malcolmnz

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Jul 26, 2018
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would it be worth looking at BBD LTM11200? cant remember if that used hook groups for the CW or not
 
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AIN_002

AIN_002

Crawler crane specialist
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would it be worth looking at BBD LTM11200? cant remember if that used hook groups for the CW or not
You're right! It uses hookgroups but doesn't have this issue now that I tested it. I'll try to investigate how it works. Thanks for the tip :)
 
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