Shape memory response of cellular lattice structures: Unit cell finite element prediction

Ashrafi, Mohammad Javad; Amerinatanzi, Amirhesam; Saebi, Zohreh; Moghaddam, Narges Shayesteh; Mehrabi, Reza; Karaca, H.E.; Elahinia, Mohammad

doi:10.1016/j.mechmat.2018.06.008

Cited by 15 publications

(9 citation statements)

References 35 publications

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“…The entire process is controlled by a chamber purged with inert gas (typically argon) to prevent oxidation during manufacturing. [29][30][31][32] The laser power (P), scanning speed (V), hatch spacing (H), and layer thickness (L) are the main effective process parameters. The volumetric energy density (VED) and linear energy density can be defined as…”

Section: Metallurgy and Biocompatibility Of Niti Smasmentioning

confidence: 99%

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Safaei

Abedi

Nematollahi

et al. 2021

JOM

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NiTi shape memory alloys (SMAs) are used in a broad range of biomedical applications because of their unique properties including biocompatibility and high corrosion and wear resistance as well as functional properties such as superelasticity and the shape memory effect. The combination of SMAs and additive manufacturing can lead to revolutionary changes to the uses of SMAs in the biomedical industry. This article discusses the potential biomedical applications of NiTi that benefit from the AM process. We share the lessons learned in processing NiTi alloys with a focus on the laser powder bed fusion (LPBF) technique. The manufacturability, build quality, stable phases and transformation temperatures, microstructure, thermomechanical properties, microstructure tailoring, and functional properties of NiTi alloys produced via AM processing are reviewed. Current challenges such as expanding the process window, controlling the chemistry, and the performance and property responses are discussed, and potential opportunities including alloy design are discussed.

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Section: Metallurgy and Biocompatibility Of Niti Smasmentioning

confidence: 99%

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Safaei

Abedi

Nematollahi

et al. 2021

JOM

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“…Figure 5(a) and (b) presents the 1/8 model for a cubic cellular structure and a 10% porous structure, respectively. More details on the unit cell FE models are presented in the previous works such as Ref 4,6,17. The material properties of both models are assumed according to Table 5.…”

Section: Computational Efficiencymentioning

confidence: 99%

Transformation and Plasticity of Shape Memory Alloy Structures: Constitutive Modeling and Finite Element Implementation

Ashrafi

2020

J. of Materi Eng and Perform

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In this work, we extend a well-known three-dimensional phenomenological shape memory alloy (SMA) constitutive model known as Souza model. The proposed model describes more precisely the hardening behavior observed during forward-and reverse-phase transformation as well as evolution of plastic strain and its effects on transformation behavior. Moreover, we present a solution algorithm for low temperatures and evolution of plastic strains which considerably reduces the computational cost. Through calibration of material parameters, the model is able to predict pseudo-elasticity and shape memory properties of SMAs more accurately compared to Souza model. Moreover, the plasticity and its effect on transformation are well predicted by the proposed model. Through finite element implementation, we can perform simulations on complex SMA structures. Finally we compare the run time for the present algorithm with the iterative Newton method used for solving equations of Souza model. The comparisons show that the computational cost of the proposed algorithm is considerably lower than previous algorithms.

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“…While representative volume elements (RVEs) are used for irregular and random cellular structures using boundary conditions. 44…”

Section: Introductionmentioning

confidence: 99%

Tension-compression asymmetric mechanical behaviour of lattice cellular structures produced by selective laser melting

Raghavendra

Molinari

Fontanari

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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Additive manufacturing is an evolving technology for fabricating porous structures used in a broad array of applications, ranging from the aerospace industry to biomedical engineering. Porous titanium alloy (Ti6Al4V) structures play a major role in biomedical implants and are preferred over conventional solid implants because their properties can be tailored to obtain the stiffness required to avoid stress shielding and improve osteointegration. The mechanical properties of these structures are dependent on unit cell topology and overall porosity. In the present work, three open cellular configurations were studied, namely regular (square), irregular (skewed square) and fully random structures, at three different porosity levels. The samples were manufactured using the selective laser melting of spherical Ti6Al4V powder. The deviations of manufactured samples from as designed were assessed using morphological characterisations and porosity analyses. The mechanical characterisations of the samples included monotonic and cyclic tensile tests, along with conventional compression tests under monotonic and cyclic conditions. The results from the study indicate a clear deviation of thickness values from as-designed values. The effect of inclination of the strut with respect to the loading axis has been studied in compression samples. The off-axis loading in compression led to the asymmetry in the Young's modulus in compression and tension. These led to finite element modelling of structures in the elastic regime and its validation using Gibson–Ashby model for cellular structures.

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Shape memory response of cellular lattice structures: Unit cell finite element prediction

Cited by 15 publications

References 35 publications

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Additive Manufacturing of NiTi Shape Memory Alloy for Biomedical Applications: Review of the LPBF Process Ecosystem

Transformation and Plasticity of Shape Memory Alloy Structures: Constitutive Modeling and Finite Element Implementation

Tension-compression asymmetric mechanical behaviour of lattice cellular structures produced by selective laser melting

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