Modelling and strength prediction of pre-tensioned hybrid bonded joints for structural steel applications

Strength prediction of bonded joints remains a challenging task made even further complicated for hybrid joints in which adhesive is supplemented by mechanical fasteners. The present paper complements a series of experimental investigations on hybrid joints combining adhesive bonding with pre-tensioned bolts on galvanised and coated stell substrates, and considering two adhesives. The paper starts with modelling the strength of the bonded connection under the simultaneous action of tensile and compressive normal stresses, and shear. It the presents how these date are moulded into appropriate failure criteria and used the latter as input data for a subsequent full probabilistic finite element analysis. Following the paths of Weibull and subsequent researchers, joint capacity is predicted with reasonable accuracy for a dozen different combinations of substrates, adhesive, and pre-tension level - for which, on average, an accuracy slightly below 10% has been achieved. The results deliver meaningful insights into the subtle relationship between adhesive bonding, mechanical fastening, failure criteria, and resulting predictions methods.