Search Results (318)

This paper presents a dual-quaternion (DQ) framework for the rigid-kinematic modeling and validation of rigid hexagonal Kresling origami robots executing a prescribed FOLD–TWIST–FOLD motion. Triangular panels are modeled as rigid bodies, and crease lines are modeled as fixed revolute axes. Exact spatial 4R closure is decomposed into a primal orientation closure and a dual transported-translation closure. Under explicit non-degeneracy, paired-normal transport, and branch assumptions, the projection of the dual closure recovers a Bennett-type axis ratio. For Kresling, this result is applied only in the intersecting-axis limit d = 0, serving as a local axis-geometry diagnostic rather than a sufficient global closure criterion. The baseline three-cell module (N_s = 6, R = 48 mm, H₀ = 60 mm, initial twist 30°) executes a (−2 mm, +5°, −2 mm) actuation command over 37 states, preserving rigid-edge/panel and DQ consistency within the prescribed tolerances. Comparative benchmarks show that DQ and homogeneous-transform mappings achieve practically identical accuracy, although homogeneous transforms run faster in the tested MATLAB 2025b workload; Direct LM is faster for computing the endpoint solution, whereas DQ-parametric homotopy provides state-by-state path certification. A generalized implementation evaluates 27 configurations (21 accepted, six rejected), with all six controlled actuation-order permutations accepted. The framework serves as a pre-prototyping rigid-kinematic qualification tool that separates local axis compatibility from global rigid-origami feasibility. Full article

Ultra-cold neutrons (UCNs) play an important role in the modern frontier of low-energy physics related to fundamental symmetries. They have enabled an improvement of two orders of magnitude in the measurement of the upper limit of the neutron electric dipole moment (nEDM) compared to beam experiments. Further improvements in both the design of UCN sources and nEDM measurements critically depend on the availability and development of materials which satisfy specific requirements. We present innovative materials used for the fabrication of the cryogenic UCN source at the PULSTAR reactor (NC State University, USA) and for the cryogenic non-magnetic environment required for a new high-precision nEDM experiment seeking a further two-orders-of-magnitude improvement in nEDM sensitivity. Full article

Origami structures are recognized for their exceptional deformability and programmability, serving as a promising platform for designing mechanical metamaterials. In this paper, a local-resonant polygonal honeycomb origami metamaterial (LR-OHS) is proposed to achieve low-frequency wave attenuation and impact mitigation. The bandgap (BG), transmission spectrum, and mode analysis are investigated in detail through numerical calculations and experimental validation. It is demonstrated that two complete BGs in the low-frequency range are found, and the underlying generation mechanism of these BGs is elucidated theoretically by establishing a mass-spring model. Subsequent research discusses the influence of three significant parameters on the two complete BGs within the region of interest, as well as the broadening of the low-frequency BGs through the merger of two narrow BGs induced by an increasing resonator radius. Furthermore, the impact resistance performance of LR-OHS is evaluated under impact pulses, demonstrating a 43.43% reduction in the peak reaction force compared to its non-resonator origami honeycomb metamaterial. Additionally, parametric analysis of the number of resonators identified an optimal configuration of eight resonators per unit cell, ensuring high performance while satisfying lightweight engineering requirements. This work establishes a design framework for origami-based metamaterials, offering a viable path toward high-performance structures for wave attenuation and impact mitigation. Full article

Composite cylindrical shells suffer from thermal buckling in harsh thermal environments, impairing overall structural safety. This study aims to improve the thermal stability of such shells by investigating the thermal buckling behavior of graphene origami metamaterial-reinforced composite cylindrical shells. Four common thickness-wise distribution patterns (UD, FG-X, FG-O, and FG-A) are adopted, and temperature-dependent material properties are taken into account. Based on classical thin-shell theory with geometric nonlinearity, thermal buckling governing equations are derived. Analytical solutions of critical buckling temperature rises are obtained via an iterative procedure for both temperature-dependent and temperature-independent material models. Parametric studies are conducted to explore key influencing factors including reinforcement distribution, filler content, folding degree, tangential edge constraints, and shell geometric parameters. The results reveal that critical buckling temperature is strongly dependent on graphene origami distribution and structural features. Increasing filler content enhances thermal buckling resistance, while folding degree also dominates structural stability. Additionally, tangential constraints and geometric dimensions exert obvious effects. Significant discrepancies exist between two material models, verifying that temperature-dependent material properties are essential for precise thermal buckling analysis of the proposed composite shells. Full article

This study investigates the quasi-static equalbiaxial compression behavior of 3D-printed Miura-ori metamaterials incorporating both out-of-plane and in-plane gradient configurations. The Miura-ori structure, composed of tessellated parallelogram units, exhibits pronounced anisotropic behavior due to its unique folding geometry. To assess this behavior, specimens were fabricated using ABS resin and subjected to equalbiaxial compression in three orthogonal directions: the xy-direction (in-plane compression), the yz-direction (edge-on side loading), and the xz-direction (accordion-like profile loading). In the out-of-plane gradient design, the acute angle ϕ was varied across layers, significantly influencing both yield stress and specific energy absorption (SEA). Compared with the uniform design, gradient configurations exhibited reduced mechanical performance in the xy-direction and yz-direction, and enhanced properties in the xz-direction. In addition, in-plane (x-direction) gradient structures were evaluated under xy-, yz- and xz- direction compression. The results indicate that gradient configuration specimens exhibit significantly lower yield stress and specific energy absorption than uniform structure specimens, with deformation initiating preferentially in regions with smaller acute angles and lower local stiffness. The results highlight the strong influence of geometric gradation and loading direction on the mechanical performance of Miura-ori metamaterials. This work provides new insights into the design and optimization of origami-inspired energy-absorbing structures for use in advanced mechanical, aerospace, and protective engineering applications. Full article

Background/Objectives: Sensory nerves, as essential peripheral nerves, innervate bone and release various neuroactive substances—including neurotransmitters, neuropeptides, and neurocrine factors—that participate in bone growth, remodeling, and metabolism. Interleukin-1 receptor antagonist (IL1RN), an endogenous anti-inflammatory mediator, is a key regulatory molecule in the pathogenesis of inflammatory diseases such as osteoarthritis and rheumatoid arthritis. However, its role as a sensory neurocrine factor in the regulation of bone tissue has rarely been investigated. This study aimed to explore the regulatory effects of sensory nerve–derived IL1RN on bone tissue. Methods: A dorsal root ganglion (DRG)-targeted delivery system was developed using DNA origami technology to load IL1RN protein or IL1RN-targeting siRNA and was functionalized with a DRG-homing peptide. Bone defect and age-related bone loss models were established in C57BL/6 mice to preliminarily investigate the regulatory role of IL1RN secreted from sensory nerve endings in bone tissue. Results: IL1RN suppressed bone resorption and promoted new bone formation at defect sites. In the age-related bone loss model, IL1RN preserved the integrity of the growth plate. These findings indicate that sensory nerve–derived IL1RN may participate in the regulation of bone repair and skeletal homeostasis. Conclusions: IL1RN may serve as a potential therapeutic target for DRG-mediated regulation of bone repair. These findings suggest that DRG-targeted modulation of IL1RN may represent a potential approach for investigating and regulating sensory nerve–associated bone repair. Full article

Amphibious robots must reconcile two distinct mechanical requirements within a compact locomotion architecture. Terrestrial operation requires limb structures with sufficient load-bearing capacity, contact stability, and bending resistance, whereas aquatic operation benefits from a larger projected area for drag-based thrust generation. Conventional amphibious platforms often address these requirements by combining separate land and water propulsion modules, which increases structural redundancy, system mass, and hydrodynamic resistance. To reduce this conflict at the structural level, this study proposes a bioinspired origami morphing limb based on a modified Yoshimura pattern. The limb transforms between a closed cylindrical configuration for terrestrial support and an unfolded planar configuration for aquatic paddling. A vertex-splitting topology and thick-panel geometric constraints are introduced to suppress the bifurcation instability associated with the zero-thickness Yoshimura vertex, thereby obtaining a deterministic single-degree-of-freedom folding path suitable for robotic actuation. A screw-theory-based kinematic model is established to relate the active driving angle to the passive folding angle, and geometric parameter analysis is used to connect the folding state with load-bearing and paddling morphologies. A quadruped amphibious robot prototype is fabricated using rigid polylactic acid panels and flexible thermoplastic polyurethane hinges. Prototype-level observations qualitatively demonstrate reversible transformation within the tested operating range and show walking, crawling, rolling, water-entry, and underwater locomotion modes. Full article

This work presents the design of a deployable reconfigurable monopole antenna based on a triangular cylindrical origami structure (TCO). TCO structures are three-dimensional geometries able to modify their structure if subjected to specific solicitations. They are particularly useful for the design of deployable antennas in satellite communication applications. A TCO structure begins from a two-dimensional base composed of an N-faced polygon around which are triangles arranged in a circular pattern to give the structure a cylindrical shape once assembled. The structure is closed with an upper face that can move when stressed. In fact, by applying a force on the upper face, the structure can bend through a combined movement of rotation and translation, expanding or contracting its physical length and consequently the operative frequency. The use of a TCO structure provides a light, cheap, compact, and reconfigurable monopole antenna, particularly suitable for satellite applications. Moreover, by using multiple TCO segments that can be singularly activated, it is possible to control the antenna’s electrical length and consequently obtain a frequency reconfigurable antenna. To demonstrate the effectiveness of such a structure, an antenna prototype based on a TCO is been designed, fabricated, and numerically and experimentally assessed. The obtained results demonstrate the potentialities of such antenna, especially for satellite communication applications. Full article

This study presents the innovative design and development of biomimetic origami-based soft robotic grippers capable of two-stage grasping. Inspired by the biological structure of the sea urchin mouth, which combines external rigid teeth with an internal soft membrane, the proposed grippers employ origami architectures to achieve coordinated two-stage grasping. Novel waterbomb and Miura-ori origami architectures were introduced, enabling the formation of external and internal teeth. The developed grippers integrate an elastomeric membrane with an internal origami structure that enables contraction-driven folding under negative-pressure actuation. Multiple gripper configurations with varying dimensions are fabricated using paper and polymer-laminated paper skeletons. An energy-based modeling framework is introduced to describe the pressure–force relationship while accounting for the effects of structural deformation. Experimental evaluations conducted at different negative-pressure values quantified grasping performance and holding force. Imprint-based analysis confirmed the two-stage grasping mechanism, while grasping capability investigations demonstrated compliant interaction with delicate objects. Holding forces were measured using cylindrical metal and spherical wooden test objects of varying sizes and orientations. The waterbomb-based gripper achieved the most consistent performance, particularly for cylindrical objects, reaching a maximum holding force of 70 N, whereas the Miura-ori provided improved adaptability and higher holding forces for spherical objects, reaching 74.8 N, and maximum force-to-weight ratios of 327.2 and 346.6 were achieved for the waterbomb- and Miura-ori-based grippers, respectively. Full article

Since its introduction in 2006, DNA origami has enabled the fabrication of a wide variety of two- and three-dimensional DNA nanostructures. From the very beginning, researchers have explored these nanostructures as programmable nanobreadboards with hundreds of uniquely addressable positions, allowing precise spatial arrangement of biomolecules, fluorophores, and nanoparticles. This capability has been leveraged to create functional DNA nanomachines capable of single-molecule detection. Here, DNA origami is utilized to precisely engineer various nanoarchitectures, such as conformational switches and plasmonic hotspots. Through coupling of these concepts with tailored readout strategies, true single-molecule detection can be achieved. This literature review systematically examines the development of DNA origami-based single-molecule detection concepts. We first explore general design principles to produce functional DNA nanostructures, followed by an overview of non-fluorescence-based approaches employing atomic force microscopy, nanopores, and optical nanoantennas with surface-enhanced Raman spectroscopy readout, as well as fluorescence-based approaches relying on dynamic DNA nanostructures and optical nanoantennas with fluorescent readout. We highlight key trends as well as the remaining technology gaps that should be bridged to further advance DNA origami towards next-generation single-molecule detection. Full article

Soft pneumatic actuators (SPAs) are widely used in applications requiring safe and compliant interaction; however, achieving bidirectional motion within a compact and predictable architecture remains a key challenge. Existing approaches typically rely on antagonistic actuator pairs or multi-chamber designs, which increase system complexity and control requirements, while single-chamber solutions often lack robust analytical models to predict their mechanical response. In this work, a Bidirectional Origami-Inspired Soft Pneumatic Actuator (Bi-OSPA) is proposed to achieve both elongation and contraction within a single-chamber structure, where the direction of motion is governed solely by the applied pressure (vacuum or positive). The actuator leverages origami-inspired geometry, allowing deformation to be primarily described through folding kinematics, which facilitates analytical modeling. An analytical framework is developed to predict actuator deformation as well as the corresponding elastic and output forces based on geometric parameters and pressure input, and is validated experimentally, showing good agreement across the displacement range. Furthermore, the effects of key design parameters on displacement and force output are investigated and characterized. The proposed Bi-OSPA combines structural predictive capability and bidirectional functionality, providing a foundation for the design and optimization of soft actuators. Its versatility is further demonstrated through applications in achieving pure twisting when integrated with a Kresling origami unit and as an actuation unit for a one-degree-of-freedom robotic finger enabling flexion and extension. Full article

This work investigates, for the first time, nonlinear wave dynamics and chaos in nanocomposite micropipes conveying a viscous fluid, reinforced with graphene origami (GOr), and subjected to thermal loading. It extends the previous study by considering the influence of a transverse load and fluid viscosity, both of which were ignored previously. The Painlevé integrability of the governing equation is tested using the Ablowitz–Ramani–Segur (ARS) algorithm. Our findings prove the non-integrability of the governing equation, motivating a qualitative dynamical approach. Bifurcation theory is applied to multiple possible forms of the transverse load. In the absence of a transverse load, neither periodic nor solitary axial wave displacements exist. This is guaranteed by applying Bendixson’s criterion and confirmed through phase portraits. However, with a specific form of the transverse load, bifurcation analysis analytically provides the existence conditions for periodic, super-periodic, and solitary axial displacement waves. Furthermore, it is shown that kink and anti-kink solutions are absent. Explicit exact solutions are constructed in terms of elliptic functions, and their consistency and validity are verified through orbital degeneracy. The key material parameters’ impacts—GOr weight fraction, temperature change, hydrogen coverage, and shear layer stiffness—on the wave profiles are inspected numerically and eludicated physically. When an additional periodic transverse load is inserted, the system manifests quasi-periodic behavior at frequencies with small loads, transitioning to chaotic motion as the frequency grows. Both Lyapunov exponents and a Poincaré section are utilized to confirm this chaotic behavior. Our findings show the impact of fluid viscosity and the transverse load structure are significant in GOr-reinforced microtubes and highlight their relevance for advanced fluid-conveying systems. Full article

Bending actuators are key components in soft robotics and other engineering applications where compact, reversible, and biomimetic motion is required. Although many bending actuators have been identified, the literature remains fragmented, with most studies organized by material type, activation principle, or application domain. This review adopts a configuration-based perspective and classifies bending actuators by geometric architecture rather than by actuation technology. Representative actuators from the literature were analyzed and grouped according to geometric mechanisms that convert input energy into curvature. The analysis reveals that diverse actuator technologies repeatedly rely on a set of recurring configuration families, including laminated, tubular, internal chambers, rolled, origami/kirigami, articulated, and hybrid structures. By emphasizing geometry, the proposed taxonomy clarifies the structural origins of bending motion and enables cross-technology comparison of bending actuators. Full article

The integration of multi-material 3D printing with origami engineering offers a promising avenue for deployable structures, but weak interfacial bonding between rigid and flexible phases remains a key limitation. This study first proposed four distinct hinge designs (enclosed, interlaced, inserted, and interlocked) for Miura-ori architectures, and subsequently investigated their mechanical behaviors with further elucidation of stress-transfer efficiency and interfacial failure modes under static tensile or compressive loading. Research outcomes identified the 5.0 mm interlaced hinge as the optimal interface design, improving stress distribution at the rigid–flexible interface and suppressing premature debonding. Notably, the dominant failure mode shifted from interfacial separation to ductile fracture within a TPU elastomer. Further research proves that increasing the embedment depth of the interlaced hinge from 1.0 mm to 5.0 mm can significantly increase fracture elongation from 100.8% to 342.4% while maintaining a stable peak tensile strength of approximately 12.5 MPa. At the structural scale, dual-material printed Miura-ori architecture exhibits better mechanical performance than single-material printed spatial counterparts (5163 N vs. 4019 N in compressive capacity, 18.7 mm vs. 8.0 mm in fracture elongation). These findings provide valuable insights into high-performance deployable structure design based on multi-material additive manufacturing. Full article

This study examines the potential of sustainable, biobased paper-based structures as panel/membrane sound absorbers. Although intact paper is naturally impermeable and a poor sound absorber, transforming it into complex three-dimensional origami geometries, specifically the Miura-ori pattern, could produce effective panel/membrane absorbers. Three distinct Miura-ori samples (A, B, and C) were fabricated with increasing geometric complexity, ranging from a simple triangular prism to a complex labyrinthine waveguide. The random incidence sound absorption coefficients of these samples were measured in a validated small-scale reverberation room. The underlying absorption mechanisms were further investigated through modal analysis and non-contact vibration velocity measurements. The results indicate that increased geometric complexity enhances acoustic performance. Sample C, the most complex structure, demonstrated the most consistent broadband absorption. The analysis confirmed a significant positive correlation between acoustic pressure modes, surface vibration velocity, and sound absorption peaks, indicating that acoustic energy dissipation is driven by the vibrational response of the paper membrane coupled with resonant modes in the air gap. This research demonstrates that tunable origami folding techniques using intact paper can be used to design lightweight acoustic treatments for diffuse sound fields in the mid-frequency range. Full article