Saved by FEA grace - Deformed state model

It’s all in the philosophy and idealization.

Today I reminisce on tackling one of the most complicated challenges of 2018; optimizing a product for functionality irrespective of deformations in a vital component.

Late last year,

I was looking at a design of a product made up of roughly 20 other components, all perfectly designed but somehow failed to empathize “naughty” installers (I will get to why I call them naughty later). Yeah, I cut the original designer some slack; he had codes, probably done same for years and may not be acquainted with the “product user demography” (being a European).

Considering major constituent materials and operating conditions, elastic deformations in plastic parts maybe acceptable as compared to likes of steel around same “displacement neighborhood" (the reason I guess you may already know, stiffness is key). If so, then relative parts must functionally operate within this “allowable deformation” range, therefore must be designed as such.

However, one stressing thing about analyzing deformations is that they are barely uni-axial, thus best estimates and optimizations inferred directly from FEA results may not always help matters.

OK, back to the problem, A major part (lets say XYZ) of the product experiences significant deformation upon installation, resulting deformations arose from associated compression force from screw’s axial loading. Yes, there are codes for screwing torque and related, but let’s face it, does the local installer care? Again, one question I keep asking, which angels whispers to tell one when to stop tightening? Yes, naughty naughty installers.

Sequel to testing, XYZ's new deformed status significantly affects operation of other relative parts threatening the functionality of the entire design. Client had already invested and started spending therefore no going back to square one (As far as i knew). Most ranked allowable tweaks were "affordable" mold modifications therefore the objective became clear "predict XYZ's deformation, optimize and redesign relating parts to work with XYZ"

This where Idealizations, assumptions and competencies of FEA play hard, believe you me, soon FEA results were everywhere, I mean, in engineering backward, data may not just be helpful even when they tell so much, the numbers and graphical estimation of deflection of typical FEA software.

Long story short; the ability of leading FEA software to export part/component in deformed solid state save the day; I had the deformed 3D solid model advice optimization of relating parts directly from general assembly.  Yes, it worked for the client. I wish it was as simple as narrated.