S-BT Threaded Fastener Specification

Table Of Contents
page 66 Specifications
5.3.3 Shear strength of S-BT threaded stud fastenings
Tension,shearandbendingtestswithS-BTscrew-inthreadedstuds,
ReportNo.279/15HTLRankweil,BautechnischeVersuchsanstalt,Febr.2016
Basematerial ref.to5.3.1
Numberoffasteningsintest ref.to5.3.1
Ultimate shear load
Theshearfailureoccursthroughbreakageofthestudinthecrosssectionofthe
tapthreadorthroughplasticdeformationoftheholeinthebasematerialwhich
leadstotiltingandpull-outoffastener.
Conclusions
•FailuremodeofthetestedS-BTstuds:
85%failedduetoshearfractureinthecrosssectionofthetapthread
15%failedduetoplasticdeformationoftheborehole⇨tilting⇨pull-out
•Theeffectofthesteelbasematerialstrengthisratherlow.
•Themostimportantparametersaffectingtheshearloadcapacityisthescrew-in
depth,thetypeofthebasematerial(steelvs.aluminum)andthematerialofthe
S-BTstud.
•Thethreadsizeoftheupperpartofthefastenerdoesn’taffecttheshearload
capacitybecausethegeometryofthetappingthreadisidenticalforallstuds
made of the same material.
V
Testsetupforshearloadtesting