Bathtub fitting with radius filler

[compositestress]

Has anyone knowledge of a method for analyzing a bathtub fitting with a radius filler added to increase capability.
This has arisen on a retrofit where they want to increase the capability but dont want to remove/replace the bathtub fitting.

Thanks in advance for your advice/assistance

 

[rb1957]

i wonder how effective this will be ?

it would depend on what was critical with the existing design. I guess you are increasing the strength on the end-pad; the radius washer will carry some of the pin load to the edge of the end-pad (so if the end-pad is critical this'll help, but if the sides are critical, i don't think you've improved things much.

do you have an analysis for the existing fitting ?

do you have lockheed SM88a ?

 

[WhiteRabbit]

I have actually seen the application of a radius filler in a bathtub fitting also on a TCTO. They added this because the main tensile loading was parallel in the ST direction. They were trying to increase the surface area of one of the tension bolts.

 

[Lurchaolot]

The radius filler (or saddle washer) has a number of benefits. One is that the fastener head/tail does not interfere/foul with the radius run-out of the fitting. This way you can locate the fastener nearer to the wall, reducing the bending moment. Another is that if you're clever, you can pre-load the fastener giving you clamping force at the tension bolt which will also reduce the bending moment at the end pad, where the moment goes somewhere between: PL < M < PL/2 i.e. where M=PL/2 is the fully clamped condition. Hope this helps. Alan T.