On the Effects of Core Microstructure on Energy Absorbing Capabilities of Sandwich Panels Intended for Additive Manufacturing

Abstract

Increasing transportation safety can be observed as one of the biggest engineering challenges. This challenge often needs to be combined with the need to deliver engineering solutions that are able to lower the environmental impact of transportation, by reducing fuel consumption. Consequentially, these topics have attracted considerable research efforts. The present work aims to address the previously cited challenges by maximizing the energy absorption capabilities of hybrid aluminum/composite shock absorbers with minimal thickness and mass. This engineering solution makes it possible to lighten vehicles and reduce fuel consumption, without compromising safety, in terms of crashworthiness capabilities. A numerical sensitivity study is presented, where the absorbed energy/mass (AE/m) and the absorbed energy/total panel thickness (AE/Htot) ratios, as a consequence of low-velocity impact simulations performed on six different shock absorbers, are compared. These hybrid shock absorbers have been numerically designed by modifying the core thickness of two basic absorbers’ configurations, characterized, respectively, by a metallic lattice core, intended to be produced through additive manufacturing, and a standard metallic honeycomb core. This work provides interesting information for the development of shock absorbers, which should be further developed with an experimental approach. Indeed, it demonstrates that, by integrating composite skins with a very light core producible, by means of additive manufacturing capabilities, it is possible to design shock absorbers with excellent performance, even for very thin configurations with 6 mm thickness, and to provide a significant increase in AE/m ratios when compared to the respective equal volume standard honeycomb core configurations. This difference between the AE/m ratios of configurations with different core designs increases with the growth in volume. In detail, for configurations with a total thickness of 6 mm, the AE/m increases in additive manufacturing configurations by approximately 93%; for those with a total thickness of 10 mm, the increase is 175%, and, finally, for those with a total thickness of 14 mm, the increase is 220%.

Heat Source Modeling and Residual Stress Analysis for Metal Directed Energy Deposition Additive Manufacturing

“…AM is in the center focus, due to its limitless design manufacturability, various customized material deposition, and ability to automate the manufacturing process, which are few key factors that capitalize over traditional manufacturing methods. AM has achieved immense growth, due to progress in several fields, such as numerical simulations, materials modeling, software development related to AM, customized powder materials preparation for AM, characterizing techniques, and so on [ 1 , 2 , 3 , 4 , 5 ]. Virtual engineering, with the help of numerical modeling, is a powerful tool for the swift progress of AM technology.…”

Experimental and numerical studies on the low‐velocity impact response of carbon fiber‐reinforced polymer anisogrid cylindrical shells

“…A notable improvement in the interfacial properties of matrix and fibers, flexural stiffness, and energy absorption capabilities were observed in that study. Recently, the energy absorption capabilities of lightweight additive manufactured metal/composite hybrid [28,29] lattice structures for shock absorbers applications have been assessed under impact conditions. The study of Miao Zhao et al [30] revealed that the functionally graded sheet lattice structures have 60% higher energy absorption than uniform sheets.…”

Additive manufactured polymeric shock absorbers for automotive applications

“…These metallic shock absorbers, even if very effective in reducing the impact peak forces, have been found to significantly increase the vehicle weight. Moreover, their energy absorption capabilities are influenced by different design parameters, as their shape and thickness [ 14 ]. However, variations of the shape and thickness are restricted by the traditional manufacturing techniques, limiting the possibilities in terms of design and material distribution in the components designed to be optimized to the energy absorption tasks.…”