This is a cylindrical PV with a 4.98" OD and a 4.375" ID and separate end caps attached. The end caps are cylindrical with a flat external face and a stepped diameter to mate with the ID of the PV. One of the end caps is shearing at the junction of the flange, see attachment. The part is...
These tests are performed in a test tank, so that low temperature is not an issue. The part that failed most recently was an end cap which is a stepped cylindrical part with an outside flange the OD of the pressure vessel and an stepped diameter that allows for O-ring glands for sealing at the...
The annealed condition was used in this application, where the heat treated probably would have been a better choice. I do have the MMPDS volume on Titanium and am aware of the properties. In areas of stress concentration this alloy tends to strain harden and react as a brittle material.
I am working here as a contractor and the material was picked by the engineer in charge of the program, apparently they have used this material in the past, but didn't try to design to a low FOS as was the attempt here was to reduce size and weight. I now believe that this alloy strain hardened...
In the course of designing and testing a PV fabricated from Ti-6Al-4V Titanium, we have experienced several catastrophic failures which seem to indicate that the material is reacting to stress concentration as a brittle material. Has anyone experience with this alloy?
I am presently in the process of designing a pressure vessel for sonar equipment to be used in depths up to 6km. After extensive manual calculations and FEA analysis we fabricated parts from the Ti-6Al-4V titanium alloy and experienced several catastrophic failures in testing, which seem to...
Not sure the tank here can get beyond the 8800psi that is approximately the pressure at 6km. There has been no control on the out-of-roundness, drawings went out without my review.
These are very small quantities, all pressure vessels will be tested. Do you have experience that nonlinear FEA analysis will produce accurate results?
We will have parts to test soon, they do have a tank capable of these pressures, but not much more. Not sure the 1.25 FOS can be demonstrated. These guys don't even have a mechanical incoming QC department, they are living on the edge. Quite a difference from the Lockheed Martin engineering...
The engineering team here (I am contract) does not want to design to those standards as it would create a bulkier and more expensive pressure vessel. I have not been able to find a copy of the ASME spec, this firm does not have a copy in house.
The loading is from uniform external hydrostatic pressure found at the 6km depth of about 8800psi. The end caps are sealed with double O-rings and are .70" thick. At this facility we do not have access to finite element analysis other than basic static, which indicates that the pressure vessel...
I am in the midst of designing a titanium pressure vessel to be deployed at a 6km (8800 psi) depth and needs to have a FOS of 1.25 minimum. The design as it now exists has an ID of 4.375" and a wall thickness of .302" and an unsupported length of 16.7". Most of the critical design equations for...
