When effecting your modification on the OEMs FE mesh, did you actually change the topology (add delete elements)? Or did you only change element properties?
Was the OEMs model an internal loads model? Was it intended for a modal solution?
Do-160 is not a 'requirement' but can be best described as an faa-recognised means of demonstrating the suitability of systems & equipment to function properly (if required) or not create a hazard when subject to the intended operating environment. The requirement driving this is 2x.1309a (or...
Sw: in the context of part 25 composite primary structures, aren't ohc design values used for static strength in order to envelope the effect of bvid, and therefore the static strength check supports the overall 'no detrimental growth' dt philosophy?
Presumably with the "low level of shear", all the panel load components are fairly low and so the panel remains stable to ultimate load? Otherwise you might want to consider what happens to your doubler when the panel buckles, or reinforce the panel such that it doesn't.
Have a read of this.
Might provide a bit more friendly guidance than the d6 doc.
https://gama.aero/documents/gama-publication-13-acceptable-practices-document-cabin-interior-monument-structural-substantiation-method-version-1-0/
Rb: yes, each subassy requires its own reserved range of node/element/prop numbers.
Model config control is a significant task even to this day, though assembling a modular model is substantially faster now.
Rb: no, not 'geometry' in the FE preprocessor sense, rather, for each major assembly I want to be able to define nodes, elements, and properties in entirely separate standalone files that can be individually version controlled, then have a single master file representing a particular design...
I am working with an airplane internal loads model. The configuration of the wing, fuselage, landing gear etc will change as the project develops, so we want to be able to version control each major subassembly independently.
For example: Airplane Configuration XYZ = Wing version 1.3 + Fuselage...
It seems out of proportion, but I suppose that reflects hownit has been designed for a relatively low density oversize payload.
There's at least a couple of airship proposals for this market. Although airships are a little fragile and awkward to handle, that might be acceptable for this niche...
Rb. The inboard portion of the spar works as a beam column. However the error relative to a pure linear analysis is probably not that large if the spar is sufficiently stiff in bending.
Shear flow is constant in all bays.
As others mentioned, the purpose of a wing box rib is manifold -
It provides a means to maintain wing aero profile under load, it prevents upper skin collapsing onto lower skin as the wing bends, conducts skin out of plane pressure loads into spars, it...
Analogous to Reason's swiss cheese model: for a project to be truly successful - from concept through first flight through to production and market acceptance- there are many holes in the swiss cheese which require concentricity.
I am doubtful of the technical integrity of most urban air...
To me it sounds like the 3 sigma psd load is intended as an equivalent static criteria load. Sometimes this is done to simplify design/abalysis in applications where vibration dominates, rather than the flight/ground static loads.
If that's the case here then it's probably not appropriate to...
