Studies on the use of lock washers? 6

[bumpjones]

Does any one know of any engineering studies performed to determine what if any affect the use of lock washers has on the integerity of s structural joint?

 

[HeviiGuy]

...best option to prevent loosening is a joint with adequate elasticity to prevent loss of installed preload. And not necessarily a joint with high preload

You're not going to get "elasticity" without preload! In most cases, the more, the better (within the limits of the fastener's strength).

Two things must be considered:
[ul]
[li]the stiffness of the bolt[/li]
[li]the stiffness of the components being clamped[/li]
[/ul]

The component's stiffness must be greater than that of the bolt's. A bolt is, essentially, a spring. This spring-effect is what keeps things clampled together. One's not going to get this without adequate preload (usually quite high) "stretching" the bolt!

On the other hand, if the component constituent parts were to be "elastic", joint separation would soon occur upon external load being applied.

Ciao,

HevïGuy

http://www.heviitech.com

 

[Tmoose]

"The best option to prevent loosening is a joint with adequate elasticity to prevent loss of installed preload."

Hence the NASA, MIL spec, etc recommendation/requirement for fastener length equalling at least 6 diameters.