Natural hazards and resulting technological disasters are currently becoming regular. In these conditions, the creation of emergency shelters is a foremost task of the government to provide the harmed population with housing units in a short time. In the framework of the integration of advanced materials and technologies into steel structures to create safe emergency shelters, experimental research is conducted into adhesively bonded steel-to-steel connections based on epoxy resin laminate. Such connections are interesting for prefabricated modular construction of emergency shelters, as they allow avoiding sectional weakening and stress concentrators common to welding and screw connections. Young’s modulus and shear modulus determined for the epoxy adhesive, are crucial parameters for accurate design. The paper studies the strain distribution in epoxy bonded steel-to-steel connections, identifies strain stages and strain concentration zones, leading to a combined cohesive-adhesive fracture. The obtained results can be used to transfer form empirical building to theoretically substantiated strength analysis of safe and reliable assemblies of prefabricated adhesively bonded steel structures.
The paper presents integrated experimental research into epoxy bonded steel-to-steel connections based on FibArm Resin Laminate+. Tensile strain distribution is identified along the sample longitudinal axis. Four strain stages (elastic, yield plateau, plastic and pre-fracture) are determined together with the evolution of localized elastoplastic strain regions on the surface of the steel plate.
Identified are a nonuniform strain distribution with alternating compressive and tensile strain regions that correlates with transitions on strain-stress curves. The maximum primary relative strain in the epoxy adhesive reaches 3.38 % and concentrates along the adhesive–steel interface
In accordance with GOST 25717-83 requirements, the shear modulus of 236 MPa and Young’s modulus are determined for the epoxy adhesive by B method and the t distribution with the confidence level of 5%. These parameters are used for a transition from empirical building to theoretically substantiated finite element analysis of the stress-strain state of the steel-to-steel connection.
The obtained results help to optimize the design of epoxy bonded steel-to-steel connections in engineering, promoting more continuous load, reduced weight and defects as compared to conventional techniques (welding and screw connections). This work confirms the efficiency of sanding of the steel surface in gaining the best adhesion and resistance to environmental impacts, which is relevant for the iron, aerospace and construction industries.