Shear Investigation Of Self-drilling Screw Connection In Steel-timber Composite Structures

The light steel-fast-growing wood system combines the advantages of both steel and timber.As one of the potential new building systems,the light steel-fast-growing wood system has application prospects in building systems such as village houses and large-span structures.Among them,the dowel-type connection is a common form,and its mechanical properties significantly affect the system.This article focuses on the connection of steel-wood self-tapping screws,and conducts research from three aspects:joint test,numerical research,and theoretical derivation.And the investigation and evaluation on the fast-growing timber is carried out.The specific research content and main conclusions are as follows:(1)166 dovetail self-tapping screw connections in the form of native wood(mainly fast-growing wood)-steel plate,integrated board-steel plate,etc.,were subjected to shear tests under monotonic load and cyclic load,and the mechanical properties such as failure mode,bearing capacity and stiffness,ductility coefficient,strength degradation coefficient and so on were obtained.The restraint of the steel plate on the screw and the embedded length of the self-tapping screw significantly affect the failure mode of the connection.(2)Theoretical derivation and mechanism analysis of the shear bearing capacity of the connected connections were carried out.On the basis of European Standard 5,GB50005-2017 and other domestic and foreign standards,the bearing capacity of the steel-timber self-tapping screw connection connection was checked by comparing the wood-wood bolt connection.Furthermore,the contribution of rope effect of steel-wood connection connections is quantitatively analyzed,and a simple calculation formula is proposed.The related research results provide a reliable design basis for the design of steel-wood composite structure stud connections.(3)A finite element analysis based on Abaqus was carried out,and each test group was simulated and analyzed according to the Hill criterion and an explicit analysis solver were adopted and compared with the test data.The influence of friction and axial component force(rope-effect)on the shear performance of joints is explored,which provides a basis for deriving and revising subsequent theories;furthermore,a variable parameter analysis is carried out and a simplified model based on spring elements is established.Established a foundation for numerical analysis at the component level.