Energy absorption and piezoresistive characteristics of 3D printed honeycomb composites with hybrid cell architecture

This study examines the effects of multilayering in sandwich panel composite structures with different corrugated core configurations under quasi‐static indentation loading. The panels were fabricated using woven glass fibers and epoxy resin via the Vacuum Infusion Process. Experiments were conducted using two hemispherical cylindrical indenters with a diameter of 20 mm (ID = 20 mm) and 10 mm (ID = 10 mm) and the behavior of the composite structure in terms of contact force and fracture mechanisms for different core corrugations (square and butterfly) were investigated in two ways with foam and without foam. The experimental results demonstrate that, among corrugated core geometries without foam, butterfly cores outperform square cores in terms of structural strength, maximum force, moment force, energy absorption, specific energy absorption, and displacement until full indentation. Moreover, the butterfly core shows a higher peak load and different failure mechanisms compared to the square core. Under loading with a 10 mm indenter, the butterfly core without foam only experienced perforation in the loading area, without fracture completely. Also, adding foam did not change failure mechanisms and mechanical behavior in the butterfly geometry. However, in the square geometry, foam filled gaps between the core, preventing fracture completely and leading to only perforation in the loading area, unlike the specimen without foam. The visual analysis during the quasi‐static indentation process revealed several significant damage mechanisms, including matrix cracking, fiber breakage, delamination, buckling and crushing of cell walls, damage to top sheets, core separation, and complete indentation of the samples.Highlights Delamination and indentation failure mechanisms were seen on the butterfly core. Skin indentation and rib fracture failure mechanisms were seen on the square core. Butterfly corrugated cores revealed the best performance without/with foam. The core shape was more effective on the strength than the foam addition.

Experimental analysis of quasi‐static indentation in composite sandwich multilayers with corrugated core

Vahidimanesh,

Gazor,

Farrokhabadi

2024

Compressive and flexural properties and damage modes of aluminum foam/epoxy resin interpenetrating phase composites reinforced by silica powder

Su,

Zhou,

Wang

2024

Interpenetrating phase composites (IPCs) can combine the advantages of each component and have a good application prospect. IPCs were prepared by combining open‐cell aluminum foam (AF) and epoxy resin (EP) in three‐dimensional space in this study. Different contents of silica powder (SP, 80, 100, 120, and 140 wt%) were added to EP to improve the compressive and three‐point bending properties of IPCs. In the bending test, acoustic emission (AE) was applied to track the bending deformation of the samples, and k‐means clustering algorithm was applied to identify the damage modes. The compressive and bending properties of IPCs increased first and then decreased with the increase of SP content, and reached the maximum when the SP content was 100 wt%, with a compressive yield strength of 74.6 MPa and a bending peak load of 1.96 kN. The performance degradation was mainly attributed to the AF/EP debonding due to SP distribution at the interface. The X‐type shear band and EP/AF debonding appeared in compression failures of AF and IPCs, respectively. The AE clustering results showed that under bending load, plastic deformation of matrix (60–200 kHz) and fracture failure (230–340 kHz) modes appeared in AF, while EP/AF debonding (60–120 kHz), EP failure (120–230 kHz) and plastic deformation of foam matrix (230–250 kHz) modes appeared in IPCs.Highlights Silica powder was added to improve compressive and bending properties of IPCs. Acoustic emission was used to monitor bending of foam and IPCs firstly. k‐means clustering was used to identify and classify bending damage patterns.

Evaluation of crush and energy absorption characteristics of corrugated origami tube by additive manufacturing

Sun,

Jiang,

Zhao

et al. 2024

Origami tube (OT) has attracted significant attention in the realm of thin‐walled structures owing to their remarkable energy‐absorption capabilities. Nevertheless, their deformation modes, particularly buckling, present considerable stability challenges. In this research, we introduce a novel corrugated structure to enhance the energy absorption and stabilize the deformation mode of OT. The corrugated origami tube (COT) was manufactured using high‐specific modulus, high‐strength, and lightweight short carbon fiber‐reinforced nylon via 3D printing, followed by axial quasi‐static compression tests. The findings demonstrate that the incorporation of corrugations in COT greatly stabilizes tube deformation, boosting energy absorption by 21.3% compared to OT and reducing the peak crashworthiness force by up to 21.37%. Finite element analysis accurately replicates the experimental performance of the COT, affirming the feasibility of the simulation. Optimization using the Non‐dominated Sorting Genetic Algorithm II (NSGA‐II) produced a Pareto front, revealing trade‐offs among various crashworthiness indicators and offering a flexible design approach to meet diverse requirements. This study provides valuable insights and guidance for the design of lightweight, thin‐walled structures.Highlights The corrugated structure effectively stabilizes deformation mode of the OT. COT significantly improves energy absorption and reduces initial peak force compared to OT. The approach of multi‐objective optimization provides a variety of solutions for different needs.