Structual Failure on linkage

[Afunplatypus]

Hello,

I have been getting a problem recently where my parts of my spaceship are unstable and cause violent sporadic movements. I didn't use any unconventional linkage methods.

I just attached an Fl-800 tank to an Fl-200 tank. When i go to the launchpad the 200 tank behaves as if it isn't attacthed and starts glitching around, ultimately causing the rocket to explode. This is making my next stage impossible to build because what happens is when the bottom, larger stage accelarates, it bumps into the 200 tank that is unstable and instead of pushing the entire rocket upwards as one entity, the bottom stage hits the top stage of the rocket as if it were colliding.

It also does the same thing when I use the rockomax brand adapter.

I must be missing something here, I've made a few rockets and this is the second time it has happened.

Images:

its hard to show what it does with screenshots but i spammed f1 while flying and notice the highlighted area in the 2 screenshots.

see how this one is on the opposite side? It moves between left and right really fast and causes the rocket to tilt and go off course and then explode.

[lammatt]

structural linkages dont break unless they were experiencing more than a few G

so... i think lowering your thrust helps

also...MORE STRUTS

[Audiopulse]

Indeed. More Struts. Also - it can happen from time to time that a tank with an engine attached to it will start to oscillate around - fix it to the next upper tank with about 3 struts. Kind of like sewing them together.

With that the connection link between both tanks becomes rigid.

[Epic DaVinci]

As usual, more struts will help.

Just put 4 struts inbetween the tanks, if you attatch them to the top of the bottom tank and then to the bottom of the top tank, you will hardly see them, but they will get rid of this oscilation.

[breakthrough]

If you intend to put a stage below what is pictured, it often helps to strut to the strap on boosters of the stage above rather than connecting everything to the center.

[Cheebsta]

The struts should fix it.

The reason? When the top of the long tank moves, that motion is greatly amplified down at the little tank. Then the little tank kicks back into place, carrying some momentum, and swings the other way. This quickly becomes a vicious cycle until one of the two, or both, get ripped off.