Hello everyone,
Thanks for your inputs so far. And a nod to SAITAETGrad - the Dan Air 707 accident report is fascinating reading (actually something I only read a couple of months ago myself).
I acknowledge it's hard to pick an MS out of the air without knowing the analysis method (FEM with a...
Hello everyone,
In consultation with our NAA, i'm currently undertaking an analysis to see whether a primary structural joint on an aircraft can be shown as fail-safe under FAR 23.572(a)(2). I'm using FAA AC 23-13A as guidance, specifically para 3-10(b):
You may also use the analytical...
Hello everyone,
As the title suggests, i'm having a look at some lugs that aren't loaded purely axially. I've come across a reference "Fatigue Testing of Transversely Loaded Aluminium Lugs" by Larsson, N in 1977. It was written at the Aeronautical Research Inst. of Sweden, Stockholm. Structures...
Hello learned forum members,
I've inherited a process for forming and heat treating some thick walled spring steel tube. The tube is 5160 steel with 0.55-0.65% C and 0.7-0.9% Cr. There is no record of how this process was developed, and it was long before my time at this company.
The process...
Hello everyone,
I've been having some fun recently developing some test models of bolted lap joints that have included a solid bolt and contact between relevant surfaces; for the purposes of learning i'm leaving friction out of the equation for the time being. So far i've found a way to get the...
Hi SparWeb and everyone,
Unfortunately the part was statically substantiated by test 'back in the day' however has had a safe life fatigue analysis performed. I have been working on characterising the internal stress in response to various load cases, and whilst a gross overload failure is...
I've just been reviewing the report from our testing service in light of your question. As each sample was a slightly different shape, it appears that yes, unique cross sectional areas have been calculated.
Hello everyone,
My company procures 92" lengths of 6061-T6 extruded aluminium. The extrusion is a hollow section with an average wall thickness of about 0.1", give or take. Recently we had cause to perform some mechanical testing on a sample of the part. We took six samples from the hollow...
Thank you to everyone for their thoughts.
tbuelna, rb1957, VE1BLL and wktaylor - I have been disappointed with the response from my QA/QC department regarding this issue, and I am considering exploring some of the more serious regulatory/legal options that everyone has described. This potential...
Hello everyone,
*For the purposes of anonymity I am going to be deliberately vague on some details, and I appreciate your understanding in advance.*
I work for an aircraft manufacturer, and I have recently discovered that we may not, in my opinion (and I stress the in my opinion bit), have the...
Thank you to everyone for their input.
The VM yield criterion itself is not being questioned, nor how to calculate it - my interest is whether it regularly appears in the typical aircraft hand calcs that many of us are familiar with.
My reaction upon first reading was not unlike these:
which...
Hello everyone,
I'm contributing a small section to a colleague's report that is showing compliance with structural aspects of FAR 23 for a fixed wing aircraft's control system. The control system is fairly agricultural, i.e. cables, bellcranks, pushrods and the like.
One component subject to...
I've just been reading FAA AD-2016-04-08 which refers to "overwing flex tees" on the B788 as being principal structural elements, the failure of which may reduce the wing's ability to sustain limit load.
What's an overwing flex tee? Is it a common feature on BCA wings? Or is it something that's...
For those whom may be interested: problem solved.
It appears ABAQUS is a little quirky when it comes to self-identifying which features to project the fastener points to. If you leave it to determine affected parts along a projection vector (IIRC the facet by facet method), some may miss out...
