UL bearing allowable in mixed material joints
UL bearing allowable in mixed material joints
(OP)
I am analysing joints that consist of metallic plates with thermoplastic (TP) skins. The load path uses a metallic plate 1 plus TP skin with load passing to a thicker matallic plate 2. The assumption for bearing is that the ult bearing joint allowable is the metallic plate 1 allowable plus TP allowable. The strain when the ult allowable is produced is different for each material and hence there is a counter-argument that says the joint allowable should be lower tahn the sum of their respective allowables.
In theory this is correct, the metallic part will strain less and hence achieve its bearing allowable first, the total allowable being the metallic plate 1 plus the portion of bearing load achieved at the same strain for the TP skin.
Does anyone have a suitable method for me to reference. Any alternative theories are welcome.
In theory this is correct, the metallic part will strain less and hence achieve its bearing allowable first, the total allowable being the metallic plate 1 plus the portion of bearing load achieved at the same strain for the TP skin.
Does anyone have a suitable method for me to reference. Any alternative theories are welcome.





RE: UL bearing allowable in mixed material joints
However, if it's b10-type allowable then that's the load at 1.0% deformation, and so in theory you could just add them.
RE: UL bearing allowable in mixed material joints
The thermoplastic in practice takes a lower load then the joint analysis suggests (a view reinforced using a FEM with flexibility of each fastener modelled). The ultimate load in the joint is less then the sum total of bearing allowable in the metallic and thermoplastic combined, so it appears that we are OK.
Thanks for your response.