Skin-core adhesion in high performance sandwich structures

Shen, Yiou; Cantwell, W.J.; Li, Yan

doi:10.1631/jzus.a1300283

Cited by 8 publications

(4 citation statements)

References 18 publications

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“…The lattice structure is hybrid (exhibit HPR) if θ is negative in a part of the structure and positive in the remaining part. The lattice beam configurations were designed with a similar theoretical relative density of 0.28 and bounding cube geometries of 100 mm × 20 mm × 20 mm, which were the same nominal dimensions used in the study by Shen et al [34]. These allowed for comparisons to be made among the different samples in order to estimate the flexural properties.…”

Section: Design and Lpbf Manufacturing Of Lattice Structuresmentioning

confidence: 99%

LPBF Manufactured Functionally Graded Lattice Structures Obtained by Graded Density and Hybrid Poisson’s Ratio

et al. 2022

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The additive manufacturing (AM) of innovative lattice structures with unique mechanical properties has received widespread attention due to the capability of AM processes to fabricate freeform and intricate structures. The most common way to characterize the additively manufactured lattice structures is via the uniaxial compression test. However, although there are many applications for which lattice structures are designed for bending (e.g., sandwich panels cores and some medical implants), limited attention has been paid toward investigating the flexural behavior of metallic AM lattice structures with tunable internal architectures. The purpose of this study was to experimentally investigate the flexural behavior of AM Ti-6Al-4V lattice structures with graded density and hybrid Poisson’s ratio (PR). Four configurations of lattice structure beams with positive, negative, hybrid PR, and a novel hybrid PR with graded density were manufactured via the laser powder bed fusion (LPBF) AM process and tested under four-point bending. The manufacturability, microstructure, micro-hardness, and flexural properties of the lattices were evaluated. During the bending tests, different failure mechanisms were observed, which were highly dependent on the type of lattice geometry. The best response in terms of absorbed energy was obtained for the functionally graded hybrid PR (FGHPR) structure. Both the FGHPR and hybrid PR (HPR) structured showed a 78.7% and 62.9% increase in the absorbed energy, respectively, compared to the positive PR (PPR) structure. This highlights the great potential for FGHPR lattices to be used in protective devices, load-bearing medical implants, and energy-absorbing applications.

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Section: Design and Lpbf Manufacturing Of Lattice Structuresmentioning

confidence: 99%

LPBF Manufactured Functionally Graded Lattice Structures Obtained by Graded Density and Hybrid Poisson’s Ratio

et al. 2022

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“…Ibrahim et al [94] performed the flexural test on a double honeycomb lattice structures finding an effective modulus similar to the one obtained from the compression test, suggesting an isotropic behavior of the structure. Finally, Shen et al [123,124] studied the skin-core adhesion resistance of multilayered structures under flexural loads.…”

Section: Bending Testmentioning

confidence: 99%

Mechanical characterization and properties of laser-based powder bed–fused lattice structures: a review

Riva

Ginestra

Ceretti

2021

Int J Adv Manuf Technol

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The increasing demand for a wider access to additive manufacturing technologies is driving the production of metal lattice structure with powder bed fusion techniques, especially laser-based powder bed fusion. Lattice structures are porous structures formed by a controlled repetition in space of a designed base unit cell. The tailored porosity, the low weight, and the tunable mechanical properties make the lattice structures suitable for applications in fields like aerospace, automotive, and biomedicine. Due to their wide-spectrum applications, the mechanical characterization of lattice structures is mostly carried out under compression tests, but recently, tensile, bending, and fatigue tests have been carried out demonstrating the increasing interest in these structures developed by academy and industry. Although their physical and mechanical properties have been extensively studied in recent years, there still are no specific standards for their characterization. In the absence of definite standards, this work aims to collect the parameters used by recent researches for the mechanical characterization of metal lattice structures. By doing so, it provides a comparison guide within tests already carried out, allowing the choice of optimal parameters to researchers before testing lattice samples. For every mechanical test, a detailed review of the process design, test parameters, and output is given, suggesting that a specific standard would enhance the collaboration between all the stakeholders and enable an acceleration of the translation process.

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“…Thus, much research efforts have been given to the problem of fracture in sandwich structures and their constituents (Farshad & Flüeler, 1998;Goswami & Becker, 2001;Hernández-Pérez, Avilés, & Carlsson, 2013;Marsavina & Sadowski, 2008;Prasad & Carlsson, 1994a, 1994bQuispitupa, Berggreen, & Carlsson, 2009;Ramantani, de Moura, Campilho, & Marques, 2010;Shen, Cantwell, & Li, 2014;Sun, Yang, & Jia, 2014;Theotokoglou & Theotokoglou, 2013). Goswami and Becker simulated a delamination crack along the face sheet/core interface in a sandwich structure using a twodimensional finite-element model (Goswami & Becker, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Mode III fracture of foam core sandwich panels with steel face sheets is investigated in Hernández-Pérez et al (2013). The interface fracture toughness of a sandwich structure is studied by Shen et al (2014). Face/core fracture in composite sandwich is investigated by Sun et al (2014).…”

Section: Introductionmentioning

confidence: 99%

Mixed-mode I/III fracture study of sandwich beams

Rizov

2015

Cogent Engineering

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The capacity of prestressed split-cantilever beam (SCB) for investigation of mixed-mode I/III fracture in foam core sandwich constructions was evaluated theoretically. The fracture was studied in terms of the strain energy release rate. In this relation, a three-dimensional finite-element model was developed. The strain energy release rate mode components were analyzed by the virtual crack closure technique. The analysis revealed that the mode I and the mode III components have maximum at the center of the crack front and gradually decrease toward the edges. Different mixed-mode ratios were generated by varying the mutual transverse displacement at the end of the sandwich SCB crack arms (in this way, the use of steel rollers with different diameters for prestressing the SCB to provide the mode-I part of the loading was modeled). The effect of the sandwich core material on the mixed-mode I/III fracture was investigated. For this purpose, three sandwich SCB configurations with different rigid cellular foams used for core material were simulated. It was found that the strain energy release rate decreases when the foam density increases. Therefore, the mixed-mode I/III fracture performance of the sandwich beams can be improved by using foams with higher density for core material.The key research activities of Prof. Rizov are in the field of fracture behavior of fiber-reinforced polymer composites, fracture in foam core sandwich structures, non-linear mechanical behavior of foam core sandwiches subjected to localized loads, and elastic-plastic behavior of structural materials. His research includes also experimental characterization, finite-element modelling, and closed form analytical solutions. He has published more than 120 scientific papers. PUBLIC INTEREST STATEMENTA theoretical study of the mixed-mode I/ III fracture in foam core sandwich SCB was performed. The study was motivated by the fact that mixed-mode I/III fracture in sandwich beams has received less attention in the literature. The basic idea of the study was that mixed-mode I/III crack-loading conditions can be generated using a prestressed SCB. The prestressing was performed by inserting a steel roller between the crack arms (in this way, the mode I component was induced). The mode III component was induced by applying a scissor-like load on the crack arms. Three-dimensional finite-element simulations were conducted. The influence of the foam core on the mixed-mode I/III fracture was studied. It was found that the strain energy release rate decreases, when the foam core density increases. Thus, the use of foam with higher density can be recommended as a means for improving the mixed-mode I/III fracture performance of sandwich beams.

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Skin-core adhesion in high performance sandwich structures

Cited by 8 publications

References 18 publications

LPBF Manufactured Functionally Graded Lattice Structures Obtained by Graded Density and Hybrid Poisson’s Ratio

LPBF Manufactured Functionally Graded Lattice Structures Obtained by Graded Density and Hybrid Poisson’s Ratio

Mechanical characterization and properties of laser-based powder bed–fused lattice structures: a review

Mixed-mode I/III fracture study of sandwich beams

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