Rheological Relaxation of OSB Beams Reinforced with CFRP Composites

Abstract

An experimental and analytical approach to the relaxation problem of wood-based materials—OSB (Oriented Strand Boards—pressed wood-based composite panels) beams, including beams with CFRP (Carbon fiber reinforced polymer) tape composite reinforcement, is presented. It is a relevant engineering and scientific problem due to the fact that wood and wood-based materials, as well as composite reinforcements, are widely used in building constructions. Their rheological properties are very important and complicated to estimate. A 10 day long relaxation test of thick OSB beams without reinforcement and with CFRP tape was performed. A four-point bending test with five different bending levels was performed, during which the reduction of the loading force was measured. A five-parameter rheological model was used to describe the rheology of the beams. The equations of this model were calculated with the use of Laplace transform, whereas the values of the parameters were calculated based on the experimental relaxation curves. A high correlation between experimental and theoretical results was obtained. A beam reinforced with CFRP tape was treated as a system with a viscoelastic element (OSB) and an elastic element (CFRP), joined together without the possibility of slipping. The equations of the mathematical model were calculated based on the assumptions of the linear theory of viscoelasticity and the convolution integral. A good correlation between experimental and theoretical results was obtained. A significant redistribution of stresses was observed during the relaxation of the reinforced beam. The reinforced beams show a higher stiffness of approximately 63% and carry proportionally higher loads than unreinforced beams at the same deflection values.

The Use of CFRP for Structural Reinforcement—Literature Review

“…The results showed that the proposed reinforcement solution was profitable on account of the strength, stiffness, and construction safety. Socha et al [120] introduced an experimental and analytical approach to the relaxation problem of the beams made of wood-like materials (Oriented Strand Boards-pressed wood-based composite panels), also the beams reinforced with CFRP tape. Rheological properties of such composites are important and difficult to estimate.…”

New investigation of delamination using the VCCT method to predict the damage in bonded composite repair plates subjected to tensile load

“…Numerous numerical investigations were conducted to assess the efficacy of a boron/ epoxy repair (Salem et al, 2018(Salem et al, , 2021Serier et al, 2016;Ru zek et al, 2015;Makwana and Shaikh, 2019;Socha et al, 2021;Rabczuk et al, 2008). The endurance and trustworthiness of structures repaired with composite patches primarily hinge on the mechanical and thermal characteristics of the adhesive layer, constituting critical elements in the examination of failure causes and the deterioration of the entire repair process (Ufklyh et al, 2019;Yu et al, 2021;Zhuang and Talreja, 2014;Rabczuk et al, 2010).…”

Application of Digital Image Correlation to Evaluate Strain, Stiffness and Ductility of Full-Scale LVL Beams Strengthened by CFRP

“…Kawecki and Podgórski [ 20 ] conducted experimental, theoretical and numerical studies on glue laminated timber beams strengthened with the CFRP laminates—proving the necessity of including cohesive stiffness of the adhesive layers in the evaluation of the stiffness of the composite wood–CFRP. Rheological relaxation of OSB (Oriented Strand Boards) beams reinforced with CFRP tape was investigated by Socha et al [ 21 ]. Authors achieved a 63% improvement of stiffness and higher carrying capacity for reinforced beams in comparison to beams without reinforcement.…”