Investigation of Quasi-Static Indentation Response of Inkjet Printed Sandwich Structures under Various Indenter Geometries

Abstract

The objective of this investigation was to determine the quasi-static indentation response and failure mode in three-dimensional (3D) printed trapezoidal core structures, and to characterize the energy absorbed by the structures. In this work, the trapezoidal sandwich structure was designed in the following two ways. Firstly, the trapezoidal core along with its facesheet was 3D printed as a single element comprising a single material for both core and facesheet (type A); Secondly, the trapezoidal core along with facesheet was 3D printed, but with variation in facesheet materials (type B). Quasi-static indentation was carried out using three different indenters, namely standard hemispherical, conical, and flat indenters. Acoustic emission (AE) technique was used to capture brittle cracking in the specimens during indentation. The major failure modes were found to be brittle failure and quasi-brittle fractures. The measured indentation energy was at a maximum when using a conical indenter at 9.40 J and 9.66 J and was at a minimum when using a hemispherical indenter at 6.87 J and 8.82 J for type A and type B series specimens respectively. The observed maximum indenter displacements at failure were the effect of material variations and composite configurations in the facesheet.

Quasi-static indentation analysis on three-dimensional printed continuous-fiber sandwich composites

“…Inkjet printing had been explored to fabricate variety of sandwich structures with different complex core designs and facesheet configurations. For example, core designs that include trapezoidal vertical pillared [18], sinusoidal vertical pillared [8], and special honeycombs [19] have been printed. Inkjet printed structures have shown shape recovery effects and better energy-absorption characteristics.…”

“…Therefore, the work to be presented in this paper is a continuation of the work done on multimaterial sandwich structures previously manufactured using Inkjet printing technique [8,18]. The quasi-static indentation (QI) properties of trapezoidal vertical pillared (core-1) and sinusoidal vertical pillared (core-2) structures are investigated under various indenter (hemispherical, conical, and flat) geometries along with AE monitoring, and the results are discussed in the articles [8,18]. Moreover, a hypothesis of the damage mechanism in sinusoidal vertical pillared structure was explained in [18], but no verification was provided regarding the proposed damage mechanism as the studies were limited to analyzing the damage using high-speed camera.…”

An Exploratory Study on the Accuracy of Parts Printed in FDM Processes from Novel Materials

“…1c) with dimensions of 20x20x20 mm. The shape and dimensions of the tested specimens are important in determining mechanical properties while strength tests (Dikshit et al, 2017). Among many models, a cube was chosen as representing the simplest geometry, shortening time and facilitating the measurement and interpretation of results regarding geometric accuracy.…”

Quasi-static indentation damage and residual compressive failure analysis of carbon fiber composites using acoustic emission and micro-computed tomography

“…It was found that AE signals can distinguish three basic failure modes such as matrix cracking, delamination and fiber breaking. In addition, Dikshit et al 14 presented AE technology to determine the quasi-static indentation response and failure modes in three-dimensional (3D) printed trapezoidal core structures. It was indicated that the major failure modes were quasi-brittle fractures under indentation.…”