Numerical modeling of the shear lag effect in GFRP as function of fiber content

Abstract With the corrosion resistance of glass fiber reinforced polymer bars, the durability of concrete structures can be improved. The tensile strength of a glass fiber reinforced polymer bar is primarily dependent on the tensile strength of the fibers and the total cross sectional area of the fibers, which are determined by the nominal diameter of the bar and the volume fraction of the fibers. Furthermore, the uneven distribution of fibers due to the manufacturing process may have a degrading effect. However, the shear lag effect also influences the strength of the bar, as it causes an uneven normal stress distribution among the individual fibers of the glass fiber reinforced polymer bars. Numerical modeling of a standard tensile test setup of a glass fiber reinforced polymer bar was performed to investigate the intensity of the shear lag effect at varying fiber volume fractions. Fibers and matrix were modeled separately assuming the matrix as an embedding continuum around the individual, non-contacting, evenly arranged, parallel fibers. The results were in good agreement with the manufacturer's data. The shear lag effect was shown to be more prominent at higher fiber volume fractions.