engleski

Brittle failure modes in reinforced and non-reinforced timber joint with large diameter fastener loaded parallel to grain

The paper presents research on the joint of timber elements with a non-standard mechanical fastener of a large nominal diameter. The failure phenomenology of joints with large diameter fasteners is described, and the ways of joint reinforcement against brittle failure are presented. For experimental research, a 49mm diameter mechanical fastener was installed into a 50mm diameter hole. Testing of the unreinforced timber element and the element locally reinforced by glass fibre fabric were compared. The impact of the fabric on the ductility and the failure mode of the joint loaded parallel to grain were examined. In parallel with the experimental research, finite element analyses were conducted with geometric and material nonlinearities in the Abaqus CAE software package. Complex modes of timber failure are defined by the UMAT subroutine and cohesion surfaces, which define the crack opening in a timber element. Tests have shown that local reinforcement around the mechanical fastener can prevent the failure mode due to tensile stresses perpendicular to grain, thereby reducing the minimum distance of the mechanical fastener from the loaded edge.

End distance, splitting capacity, local reinforcement, timber joint, large diameter mechanical fastener, UMAT subroutine

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