Recent content by jstluise

Thanks for the response. We have not observed the burst disk prior to bursting; we keep a very safe distance with proper barricading. After thinking about it a bit more, I'm convinced that the equations I referenced are only valid up to yield. At one point we performed a leakdown test by...

We have built a cold gas cannon that utilizes burst disks as the means to quickly release the built up pressure with maximum flow. The bore for the burst disk is 2" and the material is Brass 260 H02 (1/2 Hard). The disks are solid and flat (i.e. no scoring or features to promote a certain type...

I'm looking for some info/guidelines on designing bolted joints that are made to move with some resistance/friction...all without loosening the bolt. Think of a legs of a camera tripod; the legs can rotate in and out with resistance, but they never loosen. It seems the basic idea is that the...

Thanks for the link. That figure does a good job of showing how how true stress/strain compares to engineering stress/strain. I think the situation I am talking about is bit more complicated than that. I was able to dig up the plot that I was referring to: The material is Titanium 6Al-4V...

Thanks for the reply. The data I was looking at was a simple force vs. displacement curve, and based on the original geometry of the groove/notch (specifically, the minimum cross-sectional area at the center of the notch) I calculated the maximum stress at the notch. It turned out to be much...

I was looking at some tensile testing data of some round bars with grooves machined into them, and based on the geometry of the groove I could not figure out how it was possible to withstand the high loads that it was seeing. I was stumped, but by some blind luck I saw a property listed on...

Thanks for the response, but that is not quite what I am after. Basically I am looking for an equation for angular deflection due to axial loading (ie change in height) with both ends free to rotate. I'll focus my search on finding it for a regular (non-conical) compression spring, then I can...

I am designing a constant pitch, helical conical compression spring (round wire cross section) that will be compressed into a final desired shape. So my issue at hand is figuring out the pre-compressed geometry that will give me my desired final geometry once compressed. The compression will...

The analogy I made with the rubber band shooting makes the most sense to me thus far. Assuming that the each half of the broken bolt are the same mass, and the plates are infinitely stiff, then the elastic potential energy in the bolt divided in half and each half of the bolt will be...

I can totally understand how the potential energy in the plate could cause the bolt to accelerate and shoot out; the plate is essentially a spring in compression that is all of a sudden released when the bolt breaks. But, when the bolt is being pulled apart, it is always in tension like an...

Thanks for responding, AlephZero. I think you are onto what originally made me start thinking about this. When the broken bolt is launched, is it from the built up potential energy from the joined material forcing the bolt apart? Or is it somehow from the strain energy in the bolt? This...

Ah yes, thanks for pointing that out. Glad we are on the same page.

I see what you did, but that stored energy is only considering the elastic deformation of the bolt. What you are describing is essentially the elastic potential energy (1/2*k*x^2) using the equivalent spring constant from the bolt properties. If the bolt all of a sudden broke (i.e. no energy...

Thanks for the reply. Could you summarize your results? What we are trying to figure out is out of all the energy put into the system to break the bolt (area under force/displacement curve), how much of that is dissipated in the fracture of the bolt, and how much of it is dissipated in the...

When a bolt is pulled in tension and eventually fractures, is all the built up strain energy dissipated in the formation of the new surfaces? Does any energy do into accelerating the broken halves of the bolt? Imagine that two plates are bolted together. As the two plates are forced apart...