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. 2025 Jan 28;18(3):599.
doi: 10.3390/ma18030599.

An Innovative Approach to Tailor Sandwich Core Structures for Multi-Directional Loading Scenarios

Samir Candelaria Caraballo  1 , Marco Menegozzo  1 , David Serrano Acevedo  1
Affiliations

An Innovative Approach to Tailor Sandwich Core Structures for Multi-Directional Loading Scenarios

Samir Candelaria Caraballo et al. Materials (Basel). .

Abstract

Enhancing the mechanical properties of sandwich core structures is important for crashworthiness applications, including protecting passengers and payloads. Existing structures, such as prismatic cells, present limitations like reduced lateral mechanical properties, among others. Non-prismatic reinforcements (NPRs) are introduced as an alternative to developing core structures tailored for multiple loading scenarios. Several NPR ideas are presented. While additive manufacturing allows for exploring the inner space of core structures with different NPRs, manufacturing such structures may present challenges due to their complexities. One of the NPR ideas was combined with the hexagonal honeycomb, a sandwich core widely used for crashworthiness applications, to create a non-prismatic reinforced honeycomb (NPRH). Utilizing fused filament fabrication, NPRH specimens were manufactured as self-supporting structures at three scales. Quasi-static compression experiments were performed in multiple loading directions. Because comparing structures' mechanical properties in multiple loading directions simultaneously may present difficulties, the multi-direction comparison factor and the angle comparison factor are presented as alternatives that relate mechanical properties in multiple loading directions and that can be adapted to different loading scenarios. These parameters were used to compare the NPRH with structures from the literature. The NPRH showed greater specific energy absorption, positioning it as a possible solution for multi-loading crashworthiness applications.

Keywords: 3D printing; axial loads; energy absorption; fused filament fabrication; honeycomb; lateral loads; reinforcements.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Typical force vs. displacement curve for honeycombs.
Figure 2
Figure 2
EA efficiency vs. deformation curve.
Figure 3
Figure 3
ACF values.
Figure 4
Figure 4
NPR Idea 1: Asterisk NPR 1. (a) Top view; (b) cross-section; (c) NPR.
Figure 5
Figure 5
NPR Idea 2: Asterisk NPR 2. (a) Top view; (b) cross-section; (c) NPR.
Figure 6
Figure 6
NPR Idea 3: Asterisk NPR 3. (a) Top view; (b) cross-section; (c) NPR.
Figure 7
Figure 7
NPR Idea 4: Spring NPR. (a) Top view; (b) cross-section; (c) NPR.
Figure 8
Figure 8
NPR Idea 5: Snowflake NPR. (a) Top view; (b) cross-section; (c) NPR.
Figure 9
Figure 9
NPR Idea 6: Not-center NPR. (a) Top view; (b) cross-section; (c) NPR.
Figure 10
Figure 10
NPR Idea 7: Tree NPR. (a) Top view; (b) cross-section; (c) NPR.
Figure 11
Figure 11
NPR Idea 8. (a) Top view; (b) cross-section; (c) NPR.
Figure 12
Figure 12
NPR Idea 9. (a) Top view; (b) cross-section; (c) NPR.
Figure 13
Figure 13
NPR Idea 10: Asterisk NPR 4. (a) Top view; (b) cross-section; (c) NPR.
Figure 14
Figure 14
NPR Idea 11: (a) Top view; (b) cross-section; (c) NPR.
Figure 15
Figure 15
NPR Idea 12: Asterisk NPR 5. (a) Top view; (b) cross-section; (c) NPR.
Figure 16
Figure 16
NPR Idea 13: Asterisk NPR 5. (a) Top view; (b) cross-section; (c) NPR.
Figure 17
Figure 17
NPRH dimensions.
Figure 18
Figure 18
Three-dimensional-printed specimens.
Figure 19
Figure 19
Loading directions represented by arrows: (a) axial; (b) Lateral 1; (c) Lateral 2.
Figure 20
Figure 20
Test setup.
Figure 21
Figure 21
Force versus displacement of NPRH-2 under axial loading. The circles indicate the points where the densification starts.
Figure 22
Figure 22
NPRH-2 under axial compression loading during an experimental test: (a) linear elastic deformation; (b) plateau; (c) densification.
Figure 23
Figure 23
Force versus displacement of NPRH-2 under Lateral 1 loading. The circles indicate the points where the densification starts.
Figure 24
Figure 24
NPRH-2 under Lateral 1 compression loading during an experimental test: (a) linear elastic deformation; (b) plateau; (c) densification.
Figure 25
Figure 25
Force versus displacement of NPRH-2 under Lateral 2 loading. The circles indicate the points where the densification starts.
Figure 26
Figure 26
NPRH-2 under Lateral 2 compression loading during an experimental test: (a) linear elastic deformation; (b) plateau; (c) densification.
Figure 27
Figure 27
NPRH-2 average SEA with 95% confidence intervals.
Figure 28
Figure 28
Force versus displacement of NPRH-1 under Lateral 1 loading. The circles indicate the points where the densification starts.
Figure 29
Figure 29
Force versus displacement of NPRH-3 under Lateral 1 loading. The circles indicate the points where the densification starts.
Figure 30
Figure 30
Average SEA for the experiments under Lateral 1 loading with 95% confidence intervals.
See this image and copyright information in PMC

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