An experimental and analytical investigation is carried out to examine the in-plane compressive response of pyramidal truss core sandwich columns. The identified failure mechanisms include Euler buckling, shear buckling and face wrinkling. The operative mechanism is dependent on the properties of the bulk material and geometry of the sandwich columns and analytical formulae are derived for each of these modes. Failure maps are constructed for sandwich columns made from an elastic ideally-plastic material and AISI 304 stainless steel which has a strongly strain hardening response. Pyramidal core sandwich columns made from 304 stainless steel have been designed using these mechanism maps and the measured responses are compared with the analytical predictions. Finally, optimal single layer and multi-layer pyramidal sandwich column designs that minimize the weight for a given load carrying capacity are calculated using the developed analytical models for the failure of the sandwich columns. The results demonstrate that pyramidal core sandwich columns outperform the currently used hat-stiffened column design.
Lightweight metallic truss structures are currently being investigated for use within sandwich panel construction. These new material systems have demonstrated superior mechanical performance and are able to perform additional functions, such as thermal management and energy amelioration. The subject of this paper is an examination of the mechanical response of these structures. In particular, the retention of their stiffness and load capacity in the presence of imperfections is a central consideration, especially if they are to be used for a wide range of structural applications. To address this issue, sandwich panels with pyramidal truss cores have been tested in compression and shear, following the introduction of imperfections. These imperfections take the form of unbound nodes between the core and face sheets-a potential flaw that can occur during the fabrication process of these sandwich panels. Initial testing of small scale samples in compression provided insight into the influence of the number of unbound nodes but more importantly highlighted the impact of the spatial configuration of these imperfect nodes. Large scale samples, where bulk properties are observed and edge effects minimized, have been tested. The stiffness response has been compared with finite element simulations for a variety of unbound node configurations. Results for fully bound cores have also been compared to existing analytical predictions. Experimentally determined collapse strengths are also reported. Due to the influence of the spatial configuration of unbound nodes, upper and lower limits on stiffness and strength have been determined for compression and shear. Results show that pyramidal core sandwich structures are robust under compressive loading. However, the introduction of these imperfections causes rapid degradation of core shear properties.
The compression response of extruded aluminum 6061‐T6 corrugated core sandwich columns is investigated. Analytical equations that predict the collapse load are used to generate failure mechanism maps. From these maps dominant failure mechanisms can be identified as a function of various geometric parameters and material properties. Experimental testing and numerical simulations are performed to test the fidelity of the analytical predictions. Fabrication of the sandwich panels involves extrusion of an aluminum billet through a specially designed die. To create longer columns the extruded panels are joined together using friction stir welding (FSW). Studies of the thermo‐mechanically affected zone (TMAZ) show that the hardness within these regions drops by approximately 50%. This significantly influences the observed failure load and failure mechanism and hence heat treatment post welding is required to ensure uniformity of properties. Good agreement is achieved between the predictions and experiment. Lastly, optimal designs are calculated based on the analytical analysis and results compared with hat‐stiffened and truss core sandwich columns.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.