Aloft Dev Log 3: Riveting Stuff
So still just been working on possible methods to simulate the structural parts of rigid airships. Annoyingly most of the approaches I've come up with don't actually look any better than the gif of the denting girder I posted previously - however they do work just as well AND seem able to produce something somewhat close to the real data I have access to; my next task is to tweak the most promising method for maintaining girder rigidity so that it follows the data.
Here's a quick picture of the method I'm thinking of using:
To explain, this shows a girder supported by two immovable points (green triangles) with a small round weight resting on it; I chose this setup as it mimics the testing setup used to obtain the real world data I have.
The girder is 5 meters long and as you can see is composed 5 sub-pieces, each of which are connected by very simple free spinning "revolute" joints (I've highlighted two of these with red dots). Now if this system were left to it's own devices it would of course simply collapse as there is no force keeping the girder rigid.
To create that force I have added a second kind of connection between the neighbouring sub-parts of the girder, which is a simulated "spring" connecting the mid point of each part to that of its neighbour; I've illustrated this for one of the pairs of girder parts with the green dots and connecting line. This solution works well as no matter which way the joint in the girder bends the spring will produce a proportional force attempting to straighten it out.
It's probably worth me saying again that I am aware that running what is essentially a physical finite element simulation of every major girder in an airship (50 longitudinal girders alone for a larger ship) is probably a bit ambitious, but I'm willing to give it a try before falling back to something more simplistic if needed.
Anyway this has been a bit of a boring and short update, so in compensation here are some gifs of some of the less successful attempts I made at getting the girder simulation working.