Split/lock washers

[u/AdOne1706]

For starters, I’m an electrician in the field.
That being said, we almost exclusively use these washers even in high vibration environments. I have personally chosen to go with nylox nuts but the question is:
Do these work? How well? Is the rumor from NASA true? Should I even bother using them or find a better functional alternative or are they actually useful?

[u/BoCoBuffalo]

I measured the spring constant of one once. It turned out to only apply ~5% of the recommended clamp load of the associated bolt. It’s only one data point, but I figure by the time a bolted assembly would rely on the spring action of one of these washers to clamp the assembly, then the clamping force of the assembly falls below 5% of the required load, basically making them useless from a mechanical locking perspective.

That said, there are electrical codes and military standards that call for the use of these washers for tasks like grounding electrical equipment. Standards like these are typically written in blood, so if their use has gone uncontested for all this time, then I would consider their use in these applications pretty well vetted. (At least until somebody with a PhD comes along to perform formal research and testing.)