Flexural behavior of functionally graded polymeric composite beams

Abstract

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.

An Assessment of ASTM E1922 for Measuring the Translaminar Fracture Toughness of Laminated Polymer Matrix Composite Materials

“…Those can be obtained from Refs. [ 40 , 41 ] and are tabulated in Table 4 . is a coefficient that determines the contribution of the shear stress to the fiber tensile initiation criterion.…”

Research on mechanical and erosion behavior of stepped polymeric functionally graded materials reinforced with aluminum

“…[38,39] Furthermore, the tensile strength of M2 was between that of M1 and M2 due to insufficient interfacial bonding between the layers owing to room temperature curing. As reported by Atta et al [40] and Othman et al, [41] volume percentage of filler at the top surface significantly improve the flexural strength of FGMs. Failure of samples in flexural loading undergoes various stages from bottom to top.…”

“…Figure 5A represents the flexural strength of pure epoxy and PFGMs samples. It was observed that flexural strength of epoxy enhanced with the incorporation of aluminum particles.As reported by Atta et al[40] and Othman et al,[41] volume percentage of filler at the top surface significantly improve the flexural strength of FGMs. Failure of samples in flexural loading undergoes various stages from bottom to top.…”

Bending and Shear Behaviour of Waste Rubber Concrete-Filled FRP Tubes with External Flanges

“…Simply supported boundary conditions were employed at the support elements. When any component of the FRP tube in the model exceeds the corresponding maximum tensile stress limit of the material, the failure of the specimen was identified [ 42 ].…”