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Materials Science in Additive Manufacturing                           Hybrid lattice structures design with AI



            of  lattice structures.   Efforts  were  made  by  researchers   costs. Particularly beneficial for addressing high-complexity
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            to investigate different cell topologies to improve the   challenges characterized by a multitude of design
            mechanical responses of lattice structures. 14-19  parameters, such as those encountered in the architecture
              Lattice structures inspired by triply periodic   design of lattice structures, AI algorithms excel due to their
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            minimal surfaces (TPMS) have captured increasing   rapid and reliable nature.  Research indicates that machine
            attention within the research community due to their   learning algorithms have significantly accelerated the
            promising combination of lightweight properties and   process of lattice structure design compared to conventional
            high mechanical performance. 20-22  Mathematically,   methods, such as trial-and-error or analytical physics-based
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            TPMS is characterized by zero mean curvature, three   approaches.  Moreover, the advance of new technologies
            dimensionally periodic, and smooth topology, which   has not only facilitated quicker solutions but has also
            is achieved through the minimization of an area within   enabled the discernment of previously unseen correlations
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            defined surface boundaries. In practical terms, structures   between design parameters and mechanical performance.
            with TPMS-like topologies can be modeled using level-  The growing demand for novel structures with distinctive
            set approximation methods.  Two primary strategies   functionalities serves as a driving force for researchers to
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            are employed in generating a TPMS-based lattice. In   explore innovative approaches aimed at accelerating the
            the network phase TPMS structures, one sub-domain   development and discovery of novel architectures. Efforts
            of the space isolated by the surface is filled with a solid   toward automating the design process and enhancing the
            material, while the matrix phase is formed by assigning   evaluation rate of new structures have been underscored in
                                                                            41,42
            thickness to the TPMS surface.  Evaluation of the   recent literature.   This necessitates the establishment of
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            mechanical properties of TPMS-based lattices has been   frameworks that utilize various AI techniques to streamline
            carried out using various materials such as stainless   these processes. Indeed, the pivotal role of AI in advancing
            steel,  aluminum alloy,  polymer 26,27  and concrete, 28,29    the field of metamaterials is becoming increasingly evident;
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            illustrating superior properties to conventional strut-  as it facilitates the automation of labor-intensive discovery
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            based structures. Furthermore,  the geometry of  TPMS-  processes and unveils previously unnoticed patterns.
            based structures can be tailored locally, as it is controlled   With the aim of accelerating the design of hybrid
            by  mathematical  equations. 30,31   For  instance,  Maskery   lattice structures inspired by TPMS, this work explores
            et al. demonstrated the feasibility of designing TPMS-  the potential of predicting the mechanical properties of
            based lattices with graded relative density, resulting in   complex hybrid lattice structures using machine learning
            customized collapse behaviors and enhanced energy   methods. First, the strategy to design hybrid lattices
            absorption under compression.  Al-Ketan et al. proposed   with TPMS-like unit cells, the homogenization method
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            a novel class of stochastic cellular structures inspired   to generate datasets for training, and the architecture of
            by TPMS, presenting superior mechanical responses at   artificial neural networks are introduced in the paper.
            high relative densities.  Recently, Maskery and Ashcroft   Then, the dataset evaluation, performance of the model,
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            proposed the concept of designing honeycomb-like   and further validation by finite element (FE) modeling
            structures based on TPMS.  Peng et al. investigated the   are discussed. Finally, the key findings of this work are
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            multifunctional properties of hybrid honeycomb-like   presented.
            lattices based on TPMS, revealing exceptional mechanical
            properties and tunable responses.  These TPMS-based   2. Materials and methods
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            honeycomb-like structures presented superior mechanical   2.1. Design of TPMS honeycomb cell
            properties compared to traditional honeycomb structures.
            Meanwhile, hybrid structures can be designed based on   Mathematically, minimal surfaces are surfaces with zero
            different unit cells to exhibit distinct properties that are   mean curvature at a given point  H = 0    (I)
            not possible with monolithic structures. However, the   where  H=(k  +  k )/2; and  k  and  k  represent the
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            complexity of these structures presents challenges in their   principal curvatures in orthogonal planes. 47
            design and property evaluations.
                                                                 The normal unit vector of the surface maintains a zero
              In recent years, there has been a notable surge in interest   divergence across all points, and the Gaussian curvature of
            regarding the  application of artificial intelligence (AI)   the surface is expressed as follows:
            and machine learning in the designs of metamaterials. 35-38    K = kk                          (II)
            Notably, neural networks and evolutionary algorithms    12
            have emerged as prominent examples, offering expedited   When a minimal surface is replicated infinitely and
            problem-solving capabilities with reduced computational   periodically throughout three-dimensional (3D) space, it



            Volume 3 Issue 2 (2024)                         2                              doi: 10.36922/msam.3430
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