Effect of ply position switching in quasi-isotropic glass fibre reinforced polymer composite subjected to low velocity impact

Abstract

This paper reports the influence of woven (0°/90°) and (±45°) lamina position interchanging about the midplane in an eight-layered quasi-isotropic glass fibre reinforced polymer (GFRP) composite under low velocity impact (LVI). In order to fabricate GFRP composite, two lamina orientations as (0°/90°) (referred as ‘a’) and (±45°) (referred as ‘c’) arranged in different stacking sequences. Three number of sample groups as (i) sandwiched ([aacc]S and [ccaa]S) (ii) intercalated ([acca]S and [caac]S) and (iii) alternate ([acac]S and [caca]S) resulted in six number of stacking sequences. The drop weight impact tests are performed at two incident velocities as 1.5 and 4 m/s. The corresponding impact energies generated are 11.39 and 81.05 J, respectively. The impact velocity 1.5 m/s created the barely visible impact damage (BVID) in the GFRP composite, while the impact velocity 4 m/s perforated the GFRP composite. The experimental results showed that the intercalated laminate design with four mismatching interfaces (i.e., [acca]S), offered better impact resistance than two other designs with two and six angle mismatching interfaces. It is also perceived that the impact response (maximum peak load, maximum impact energy and minimum impactor displacement) was independent of the number of angles of mismatching interfaces. Moreover, low velocity impact response of a quasi-isotropic GFRP composite depends on the balanced lamina position about the midplane in the laminate. Experimental results for maximum peak load, maximum energy absorption and laminate displacement proved the significance of conventional designing methodology. Further, the impactor displacement value at maximum peak load and the landing displacement value of the descending portion of the force-displacement curve after reaching the maximum peak load proved to be a practical approach along with the use of determinant of the bending stiffness matrix in determining the better performing stacking sequences for a quasi-isotropic GFRP composite made of (0°/90°) and (±45°) plies under LVI.