EXPERIMENTAL AND FINITE ELEMENT INVESTIGATION OF LOW-VELOCITY IMPACT BEHAVIOUR, EQUIVALENT STRESS AND STRAIN RESPONSE OF Fe2O3-REINFORCED GFRP HONEYCOMB SANDWICH PANELS
Rathika M1., Paul Vizhian S2., Ashwini V.3
1,3Research Scholar, 2Professor, Department of Mechanical Engineering, University Visvesvaraya College of Engineering, Bangalore University, Bangalore, Karnataka, India.
1Assistant Professor, Dr. Ambedkar Institute of Technology, Bangalore, India
Abstract: Low-velocity impact resistance is an important design requirement for lightweight sandwich structures used in transportation, aerospace, marine and other engineering applications. This study investigates the impact response of GFRP face-sheet, foam-filled honeycomb sandwich panels reinforced with different iron oxide (Fe2O3) contents under instrumented drop-weight impact loading and validates the response using ANSYS Explicit Dynamics. Four reported compositions, 0, 1, 3 and 5 wt.% Fe2O3, were tested using a 3 kg hemispherical steel impactor released from a height of 1 m, corresponding to an impact energy of approximately 29.43 J. The experimental results showed a progressive increase in peak impact force and absorbed energy with Fe2O3 addition, accompanied by a reduction in maximum displacement. The 5 wt.% specimen exhibited a peak impact force of 63 N, a minimum reported experimental displacement of 6.4 mm within the composition series, and approximately 26 J absorbed energy. Post-impact observations indicated reduced indentation, delamination, matrix cracking and core damage as the Fe2O3 content increased. The validated finite element model predicted a peak contact force of 61 N, maximum deformation of 6.32 mm and absorbed energy of 27.2 J, with errors of 3.17%, 2.77% and 4.62%, respectively, relative to the reported experimental validation values of 63 N, 6.50 mm and 26.0 J. The numerical stress and strain fields provided additional insight into local impact response. The maximum equivalent (von Mises) stress was approximately 268 MPa and was concentrated directly beneath the hemispherical impactor. The equivalent elastic strain was also localized beneath the impactor and decreased toward the clamped boundaries; the supplied study does not provide a numerical maximum strain value, so no unsupported numerical strain value is introduced. The combined experimental and numerical results demonstrate that Fe2O3 reinforcement improves impact resistance and energy absorption, while the validated explicit-dynamics model provides useful insight into deformation, stress concentration and strain localization.
Keywords: GFRP sandwich composite; honeycomb core; Fe2O3 reinforcement; iron oxide nanoparticles; low-velocity impact; drop-weight impact; energy absorption; peak contact force; deformation; equivalent elastic strain; stress concentration; strain localization; ANSYS Explicit Dynamics; finite element validation.
VOLUME 10 ISSUE 08 2026: 87 – 105