Quasi-Static Indentation and Low-Velocity Impact Response of Aramid/Epoxy Composites

Abstract

In applications that require impact loading, polymeric matrix composites reinforced with aramid fibers stand out, especially in relation to metals, due to characteristics such as high specific strength and stiffness, which give rise to light high-performance systems. However, such structures can fail through various modes, requiring comprehensive studies. Under lowvelocity impact, the contact time between the impactor and the target is relatively large, and the effects of deformation rate and wave propagation are generally insignificant, allowing association of the damage caused in the composites via drop-weight (DW) to those of quasistatic indentation (QSI) tests, optimizing the overall material understanding. Thus, this work aims to comparatively analyze force × displacement curves and resulting damage from dropweight and QSI tests. For that, laminates (2.5, 4.5 and 7.0 mm thick) were tested using variable impact energies (15, 30, 45 and 60 J) and displacement (11, 12 and 15 mm). Similarities in force × displacement curves and damage mechanisms between QSI and DW results were observed at the perforating threshold. However, to compare the response of the material and the damage mechanism generated by QSI and Drop-weight tests in composites, care must be taken, since there are many variables involved and the response of the composites to these tests will depend on such variables.

Quasi-Static Indentation Response of Galvanized Iron Toughened Glass Fiber/Epoxy Laminates

“…For safety and economical reason of the aircraft, it is crucial to understand the impact damage regime, hence different type of impact tests was instigated, for example quasi-static indentation, low-velocity impact, high-velocity impact, and blast loading. Quasi-static indentation are often selected to analyze the damage events occurring during low velocity impacts since the maximum transverse force and displacement can be better controlled in this type of test [4], [7].…”