A Comparative Study on Drill Tool Effect on Vibration and Delamination Characteristics of FRPs

Drilling is an inevitable process for component assembly which need appropriate control aiming damage reduction. To study such drill-induced damages, Glass and Natural fiber composites with unidirectional (11) and cross-ply lay-up (12) were drilled using Twist and Annular Core drill tool of varying diameters (6 and 8 mm). The derivative of modal analysis (natural frequency, damping) and delamination are the factors considered for the analysis. In the chosen laminates, maximum variation in the natural frequency was observed to be 8.98% in N12 and 8.60% in G12 for twist drill of 8 mm, whereas the core drill of 8 mm contributes to 0.51% and 0.54%. A similar trend was observed in damping factor showing a maximum variation of 26.98% (N12) and 11.30% (N12) with 8 mm twist and core drill, respectively. Similarly, the maximum delamination factor was observed to be 1 .62 and 1.30 with 8 mm core drill in G12 and N12 which is lower than the 6 and 8 mm twist drills. Further, twist drilling experiences both peel-up and push down delamination in N12, N11 which was eliminated by the core drill. Thus, core drill exhibits distinct advantages with reduced damage and retained structural properties

Structural integrity evaluation of cyclic loading glass fibre reinforced polymer composite by acoustic emission and heat transfer

This is an accepted manuscript of an article published by SAGE on 19/08/2022, available online: https://doi.org/10.1177/00219983221121891 The accepted version of the publication may differ from the final published version.GFRP composites experience structural changes like matrix cracking, debonding, delamination, and fibre failure on static and dynamic loading. In this work, composites with varying fibre orientation interaction angle and volume fractions are prepared and exposed to cyclic load. The cyclic load (R = 0) is a constant amplitude flexural load imposed on the cantilever beam specimen with varying frequencies (2.6, 4.6, 8.6 Hz) and cycles (up to 44 × 103). The structural integrity of the specimens on loading is examined in terms of Flexural, modulus, Acoustic Emission (AE) and heat transfer changes. The drop in flexural modulus is minimum in higher Vf = 32% laminate (A1 = 7.01%, B1 = 1.86%) than the lower Vf = 25% (A2 = 19.86%, B2 = 8.6%). The observed AE peak frequency for the induced damages is in the range of 50–100, 110–230, 245–380 kHz. The drop-in fibre volume fraction has a significant role in laminate with lower fibre interaction (Type A) to offer minimum variation (5.25%) in AE activity count which is the opposite in laminates with higher fibre interaction angle (31.75%). The step heat thermography exhibits minimum temperature difference (∆T) for moderate loading frequency and in a few cases, ∆T drops well below the virgin, insisting on in situ thermography to study the dynamic changes in composites. A fibre dominant behaviour can be observed with minimum variation in AE activity in a lower fibre interaction angle. Thus, the fibre orientation angle and fibre volume fraction have a significant role in the retention of the structural integrity of composites in dynamic loading.Published onlin

Tensile properties of basalt/jute fiber reinforced epoxy composite

AbstractExperimental analysis is carried out on the mechanical characteristics of fiber-reinforced that can be produced by adding basalt fibers to strengthened jute fiber-reinforced epoxy composites in both the warp and weft orientations. A three-parameter/three-level Design of Experiment technique called the Box–Behnken design (BBD) is used to ascertain the relationship between the input parameters and the response. Mechanical testing was done on the composite plates after fabrication to estimate the tensile strength of the composites in both the warp and weft directions. The basalt fiber content of the composite was around 0.5 wt.%, 1 wt.% and 1.5 wt.%; the sonication period was 20, 30 and 40 min; and the temperature was approximately 60 °C, 70 °C and 80 °C. In the warp and weft directions, the maximum ultimate tensile stresses are measured to be 34.03 MPa and 36.32 MPa, respectively. Analysis of Variance is used to determine the regression equation and the influence of the input parameters. The optimum ‘ultimate tensile stress’ is 40.162 MPa for warp direction and 35.445 MPa for weft direction with 1.5 wt.% filler weight, 40 min of sonication and 60 °C temperature