Hello
I am a beginner in CATIA and I made a geometric model of a motorcycle fork type DUOLEVER to study the kinematics.
Now I would like to do a static analysis to have the forces in the connections in order to size them.
I tried to produce a wireframe model based on the geometry of my kinematic model with the generative shape design tool and then simulate with generative structural analysis.
Below are the CATIA files related to my study:
kinematic model - https://drive.google.com/file/d/0B2P7aL1QJKyjUGxka0RGT0c1WDg/edit?usp=sharing
wireframe model - https://drive.google.com/file/d/0B2P7aL1QJKyjaVBlVUhMSlpubmM/edit?usp=sharing
analysis - https://drive.google.com/file/d/0B2P7aL1QJKyjeExXdGR1Q3dic2c/edit?usp=sharing
Only when I try to simulate I get an error telling me that I have a "singularity in the rotation (pivot too small)" when calculating the "factored matrix". I tried to play with the mesh size and it doesn't change anything.
As for the connections I don't see where the problem is, I put the ball joints between the wishbones and the fork and the pivots between the wishbones and the frame.
Then, I plan to place sensors to measure the forces at the level of the connections.
Thank you in advance. Adrien.
Hello Adrien,
I haven't opened your templates yet but you don't need to create a wired template for GSA
you create your real part, you impose the constraints, effort you want and you start the calculation
PS uses force density for the effort of pushing.
I look at your links and see you again
from what I saw it seems to come from the fact that my connections are not well defined and that in the analysis CATIA does not see my different connected parts ...
Regarding the fact of using a wireframe model, I was asked to do it like this to differentiate the kinematic analysis from the sizing
making one is not long in practice because I am modeling myself on the geometry already created but where I block is to define the connections between my different polylines and with the outside
Thank you for your help!
1 Like
Re adrien,
I can't get your models back.
Do you have the doc for GSA?
Ps: the easiest way is to work in one part at the beginning
Hello Frédéric,
I slightly modified my template and I put the two files in a .rar archive downloadable here: https://drive.google.com/file/d/0B2P7aL1QJKyjYnlHNWxpRksxaTA/edit?usp=sharing
There is a file that contains a parameterized sketch (my kinematic model) and a geometric set (made with generative shape design) that represents the beams (poly straight) of my structure that I want to do the static analysis of. And then another file (the static analysis) where I defined the fasteners and connections between my beams (via analysis connections).
Where I get stuck is for the calculation of the solution to one load (distributed force).
In addition, to put sensors (reaction measurements) at the level of the links, I can't select the entities on which to apply them.
I'm a beginner in CATIA and I don't see what's wrong with my method. Can you launch the models I put in the archive in CATIA? If so, do you see where I defined my bindings/connections (because that's where it seems like I'm doing it wrong)?
Thank you for your help!
Adrien.
1 Like
In fact I think I managed to solve my problem, I wasn't blocking the right degrees of freedom...
Now it finally wants to calculate and I managed to put my sensors directly on my bindings / connections!
I'm going to move forward on my project and I'm probably thinking of getting stuck on other points... I'll keep you posted.
Apart from that, in my kinematic model I have a length that represents the up/down of my bike (in a horizontal position) and therefore that steers the plunge of my fork. I would like to make an animation in DMU kinematics between two extremal values (low and high position) by varying this quantity. My mechanism is well constrained/parameterized so normally everything is articulated without problem.
I haven't found a tutorial for that, anyone have one? Or could he explain to me how to make a cinematic animation by playing with a parameter in my sketch?
Thank you in advance.
Adrien.
1 Like
Hello Adrien,
Are you in the CATIA V5 group under lynkoa?
Otherwise I invite you to join the group.
In the group there is a list of tutorials with what you are looking for it seems to me.
Do you have the documentation of the GSA modules? Answer
About the tutorial, I saw a paid one on the kinematics module.
Is this the one you were thinking of?
For the GSA doc I have nothing in particular, just an approach that I was told to apply ... And finally, having defined the connections correctly, it seems to work!
Adrien.