The Influence of thickness on residual flexural strength of composite with low-velocity impact damages: Experimental study

Abstract

Assessment of the residual strength of composite structural elements that can be subjected to low-velocity impact during operation is still a vital engineering problem. Its solution requires not only the understanding of the basic mechanisms of energy dissipation in composites but, the study of factors affecting the impact resistance of the material. The thickness is one of the main parameters that affects the mechanical behaviour of the composite at low-velocity impacts and, as a consequence, its residual strength. This paper presents the experimental study of the material thickness and impact energy influence on the residual flexural strength of woven glass fibrereinforced plastic specimens. At the first stage of the study, low-velocity impact tests with different impact energies on GFRP plate specimens with the thickness of 2 mm, 4 mm, and 6 mm were carried out. At the second stage, the beam specimens were cut out from the plate specimens with impact damages, and three-point bending tests were carried out. The dependencies of the residual flexural strength were obtained at various impact energies for all specimen thicknesses. The sensitivity of the Flexure-After-Impact test protocol to the delamination and fibre damages in the composite specimens were assessed.

Simplified Approach to Verification of Numerical Models for Deformation and Fracture Analysis of Structural Composite Subjected to High-Velocity Impact

“…The steel ring with the outer/inner diameters of 100/72 mm was used as a support fixture. More details about the low-velocity impact test procedure could be found in [13]. The impact energies were set at 10, 20, 30, 40, and 50 J by varying the height of the load drop.…”