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1. Morphable Detector for Object Detection on Demand

   https://doi.org/10.1109/ICCV48922.2021.00473  

   Zhao, Xiangyun; Zou, Xu; Wu, Ying (October 2021, 2021 IEEE/CVF International Conference on Computer Vision (ICCV))
2. Shape Morphable Hydrogel/Elastomer Bilayer for Implanted Retinal Electronics

   https://doi.org/10.3390/mi11040392  

   Zhou, Muru; Kang, Do Hyun; Kim, Jinsang; Weiland, James D. (April 2020, Micromachines)

   null (Ed.)

   Direct fabrication of a three-dimensional (3D) structure using soft materials has been challenging. The hybrid bilayer is a promising approach to address this challenge because of its programable shape-transformation ability when responding to various stimuli. The goals of this study are to experimentally and theoretically establish a rational design principle of a hydrogel/elastomer bilayer system and further optimize the programed 3D structures that can serve as substrates for multi-electrode arrays. The hydrogel/elastomer bilayer consists of a hygroscopic polyacrylamide (PAAm) layer cofacially laminated with a water-insensitive polydimethylsiloxane (PDMS) layer. The asymmetric volume change in the PAAm hydrogel can bend the bilayer into a curvature. We manipulate the initial monomer concentrations of the pre-gel solutions of PAAm to experimentally and theoretically investigate the effect of intrinsic mechanical properties of the hydrogel on the resulting curvature. By using the obtained results as a design guideline, we demonstrated stimuli-responsive transformation of a PAAm/PDMS flower-shaped bilayer from a flat bilayer film to a curved 3D structure that can serve as a substrate for a wide-field retinal electrode array. 

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3. Buckling and twisting of advanced materials into morphable 3D mesostructures

   https://doi.org/10.1073/pnas.1901193116  

   Zhao, Hangbo; Li, Kan; Han, Mengdi; Zhu, Feng; Vázquez-Guardado, Abraham; Guo, Peijun; Xie, Zhaoqian; Park, Yoonseok; Chen, Lin; Wang, Xueju; et al (July 2019, Proceedings of the National Academy of Sciences)

   Recently developed methods in mechanically guided assembly provide deterministic access to wide-ranging classes of complex, 3D structures in high-performance functional materials, with characteristic length scales that can range from nanometers to centimeters. These processes exploit stress relaxation in prestretched elastomeric platforms to affect transformation of 2D precursors into 3D shapes by in- and out-of-plane translational displacements. This paper introduces a scheme for introducing local twisting deformations into this process, thereby providing access to 3D mesostructures that have strong, local levels of chirality and other previously inaccessible geometrical features. Here, elastomeric assembly platforms segmented into interconnected, rotatable units generate in-plane torques imposed through bonding sites at engineered locations across the 2D precursors during the process of stress relaxation. Nearly 2 dozen examples illustrate the ideas through a diverse variety of 3D structures, including those with designs inspired by the ancient arts of origami/kirigami and with layouts that can morph into different shapes. A mechanically tunable, multilayered chiral 3D metamaterial configured for operation in the terahertz regime serves as an application example guided by finite-element analysis and electromagnetic modeling. 

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4. Geometry-Driven Design of Morphable Surface Structures Using Topology Optimization and Circle Packing

   https://doi.org/10.1115/1.4067921  

   Gao, Lingfeng; Zhu, Xiaoping; Tanaka, Masato; Song, Yuyang; Zhou, Yuqing; Gu, Xianfeng David; Chen, Shikui (September 2025, Journal of Mechanical Design)

   Abstract This paper introduces a new computational framework for modeling and designing morphable surface structures based on an integrated approach that leverages circle packing for surface representation, conformal mapping to link local and global kinematics, and topology optimization for actuator design. The framework utilizes a unique strategy for employing optimized compliant actuators as the basic building blocks of the morphable surface. These actuators, designed as circular elements capable of modifying their radius and curvature, are optimized using level set topology optimization, considering both kinematic performance and structural stiffness. Circle packing is employed to represent the surface geometry, while conformal mapping guides the kinematic analysis, ensuring alignment between local actuator motions and desired global surface transformations. The design process involves mapping optimized component designs back onto the circle packing representation, facilitating coordinated control, and achieving harmony between local and global geometries. This leads to efficient actuation and enables precise control over the surface morphology. The effectiveness of the proposed framework is demonstrated through two numerical examples, showcasing its capability to design complex, morphable surfaces with potential applications in fields requiring dynamic shape adaptation. 

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5. Geometry-Driven Design of Morphable Surface Structures Using Topology Optimization and Circle Packing

   https://doi.org/10.1115/DETC2024-143299  

   Gao, Lingfeng; Zhu, Xiaoping; Tanaka, Masato; Song, Yuyang; Zhou, Yuqing; Gu, Xianfeng David; Chen, Shikui (August 2024, American Society of Mechanical Engineers)

   Abstract This paper presents a new computational framework for the co-optimization and co-control of morphable surface structures using topology optimization and circle-packing algorithms. The proposed approach integrates the design of optimized compliant components and the system-level control of the overall surface morphology. By representing the surface shape using circle packing and leveraging conformal mapping, the framework enables smooth deformation between 2D and 3D shapes while maintaining local geometry and global morphology. The morphing surface design problem is recast as designing circular compliant actuators using level-set topology optimization with displacements and stiffness objectives. The optimized component designs are then mapped back onto the circle packing representation for coordinated control of the surface morphology. This integrated approach ensures compatibility between local and global geometries and enables efficient actuation of the morphable surface. The effectiveness of the proposed framework is demonstrated through numerical examples and physical prototypes, showcasing its ability to design and control complex morphable surfaces with applications in various fields. The co-optimization and co-control capabilities of the framework are verified, highlighting its potential for realizing advanced morphable structures with optimized geometries and coordinated actuation. This integrated approach goes beyond conventional methods by considering both local component geometry and global system morphology and enabling coordinated control of the morphable surface. The general nature of our approach makes it applicable to a wide range of problems involving the design and control of morphable structures with complex, adaptive geometries. 

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