We use the VonMises stress to determine if the part will fail and the principal stress to determine how to make it better. Sometimes knowing the direction is valuable.
Finer mesh = Better Results is absolutely false. If your mesh is too fine, you introduce an artificial stiffness into the equation resulting in poor or straight up wrong results.
Also, if you have any type of geometry change resulting in a stress concentration and you try to refine the mesh to...
One more thing....
Since this project is my first attempt with composites... may I pick your brains a bit.
Usually when I am running an analysis on a component, typically a machined component, I will run my analsysis then compare the analysis with a test case that is fairly simple to set up...
WOW... thanks for the replys, I deffinately have a lot to learn about composites and Abaqus.
One quick clairifcation on my composite layup.
So I have a small wing that I am selecting. The wing is made up of several curved surfaces. I have partitioned teh wing so that I can easialy select the...
A bolt has a nut on it. A screw does not.
Thanks for the information, I'll have to pull out my Shigley book. I think Juvinall has that same picture you are talking about, it referes to clamping pressure.
Thanks for the help.
desertfox,
Thanks for the reply.
This is what I get for posting half a question. [thumbsdown]
The drawing is simply a sample of one of the many products we offer that use this type of clamping configuration. All of these products have been used for more than 20 years. In the early days...
We have had some systems fail around the head in shear. Others would deform around the bolt head which causes a loss of clamping force.
The problem with modeling this as a simply supported beam is that I get very large bending moments on the order of 300 ksi which I know is not correct. I...
Because this is a poor design.
This is an antiquated system that I have to support and modify.
The goal is to get 2000 lb/inch at the left side of the drawing. Since my lever is backwards, I loose a lot of force going from the bolt to the target location.
rb1957,
We are using the bolt to apply a clamping load between componenets. We use grade 8 bolts to protect against fatigue failure because we cannot tighten the bolts up to proof load.
The design is "Funky" which is why I am having trouble.
Thanks for the reply,
John
The drawing is a sample of what I am looking for. I am tring to solve in closed form what the minimum thickness is below the head of the bolt.
I don't wan't to use FEA for this if I can avoid...
Ok, this should be simple, but I am having some difficulty.
I am trying to dictate to my designers the minimum amout of material below the head of a bolt based on the torque applied to the bolt.
T = (0.2)(Dia)(Force) <- Gives the Force due to the Torque
Then I model the plate as a simply...
