Living organisms use spatially controlled expansion and contraction of soft tissues to achieve complex three-dimensional (3D) morphologies and movements and thereby functions. However, replicating such features in man-made materials remains a challenge. Here we report an approach that encodes 2D hydrogels with spatially and temporally controlled growth (expansion and contraction) to create 3D structures with programmed morphologies and motions. This approach uses temperature-responsive hydrogels with locally programmable degrees and rates of swelling and shrinking. This method simultaneously prints multiple 3D structures with custom design from a single precursor in a one-step process within 60 s. We suggest simple yet versatile design rules for creating complex 3D structures and a theoretical model for predicting their motions. We reveal that the spatially nonuniform rates of swelling and shrinking of growth-induced 3D structures determine their dynamic shape changes. We demonstrate shape-morphing 3D structures with diverse morphologies, including bioinspired structures with programmed sequential motions.

Motion in biological organisms often relies on the functional arrangement of anisotropic tissues that linearly expand and contract in response to external signals. However, a general approach that can implement such anisotropic behavior into synthetic soft materials and thereby produce complex motions seen in biological organisms remains a challenge. Here, a bioinspired approach is presented that uses temperature‐responsive linear hydrogel actuators, analogous to biological linear contractile elements, as building blocks to create three‐dimensional (3D) structures with programmed motions. This approach relies on a generalizable 3D printing method for building 3D structures of hydrogels using a fugitive carrier with shear‐thinning properties. This study demonstrates that the metric incompatibility of an orthogonally growing bilayer structure induces a saddle‐like shape change, which can be further exploited to produce various bioinspired motions from bending to twisting. The orthogonally growing bilayer structure undergoes a transition from a stretching‐dominated motion to a bending‐dominated motion during its shape transformation. The modular nature of this approach, together with the flexibility of additive manufacturing, enables the fabrication of multimodular 3D structures with complex motions through the assembly of multiple functional components, which in turn consist of simple linear contractile elements.

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A numerical investigation was undertaken to evaluate the response of dual structural systems that consisting of steel plate shear walls and moment-resisting frames. The primary objective of the study was to investigate the influence of elastic base shear distribution between the wall and the frame on the global system response. A total of 10 walls and 30 wall-frame systems, ranging from 3 to 15 stories, were selected for numerical assessment. These systems represent cases in which the elastic base shear resisted by the frame has a share of 10, 25, or 50% of the total base shear resisted by the dual system. The numerical study consisted of 1600 time history analyses employing three-dimensional finite elements. All 40 structures were separately analyzed for elastic and inelastic response by subjecting them to the selected suite of earthquake records. Interstory drifts, top story drift, base shears resisted by the wall, and the frame were collected during each analysis. Based on the analysis results, important response quantities, such as the strength reduction, the overstrength, and the displacement amplification factors, are evaluated herein. Results are presented in terms of displacement measures, such as the interstory drift ratio and the top story drift ratio. Analysis results revealed that the increase in the strength reduction factor with the amount of load share is insignificant. Furthermore, there is an inverse relationship between the ductility reduction and the overtsrength. Figure 5. Push-over like curves.As shown in Figure 5, the base shears at the structural yield level for the wall, the frame, and the wall-frame can be found from pushover-like curves. As mentioned above, a simple hand method was developed to predict these base shear values. The estimates from simple plastic analysis were correlated with the results of nonlinear time history analysis for this purpose. The simple plastic analysis for SPSWs proposed by Berman and Bruneau [18] can be extended to dual systems. For a wall with constant infill plate thickness, the base shear at the structural yield level (V w ) can be Figure 7. Relationship between elastic and inelastic displacements.The scatter in results is attributable to the variation in ground motion characteristics. When a structure is subjected to different ground motions, the maximum force versus maximum displacement relationship is not perfectly linear. Depending on the dominant frequency of the ground motion and the structural periods, results can deviate from linearity as shown in Figure 5. Observations from Figure 8 reveal that the TSDR values are more scattered than the ISDR values. Therefore, from this perspective, using interstory drift is better than using the top story drift as an index.After investigating the results for elastic behavior, the inelastic behavior was considered next. The R and C d relationship for inelastic displacements is also given in Figure 8. The trendlines fitted to the data points have a slope of 1.35 (R = 1.35C d ) and 1.39 (R = 1.39C d ) for normali...