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We investigate the finite size effects of a three-dimensional second-order topological insulator with fourfold rotational symmetry and time-reversal symmetry. Starting from the effective Hamiltonian of the three-dimensional second-order topological insulator, we derive the effective Hamiltonian of four two-dimensional gapped surface states by perturbative methods. Then, the sign alternation of the mass term of the effective Hamiltonian on the adjacent surface leads to the hinge state. In addition, we obtain the effective Hamiltonian and its wave function of one-dimensional gapless hinge states with semi-infinite boundary conditions based on the effective Hamiltonian of two-dimensional surface states. In particular, we find that the hinge states on the two sides of the same surface can couple to produce a finite energy gap. [ABSTRACT FROM AUTHOR]

Origami-inspired mechanisms provide opportunities for deployable systems, including reflectarray antennas. There is a need for approaches to deploy and stabilize such arrays. Magnetic mechanisms show promise for meeting those needs and how methods for modelling their behaviour would facilitate their design and analysis. We demonstrate the existence of bistability in select configurations of magnetically stabilized hinges and characterize their equilibrium positions as a function of parameters estimated from simulation data for these mechanisms. Other relevant information such as potential energy, axial force data, angular position of unstable equilibria and transition values from bistability to monostability are also modelled. The results are verified through experimental torque and stability data for selected configurations of the mechanisms. This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'. [ABSTRACT FROM AUTHOR]

The Stiefel–Whitney (SW) insulator, which lacks spin‐orbit coupling and has space–time inversion (PT$\text{PT}$) symmetry, has attracted significant interest due to its fragile topological state and unconventional bulk‐boundary correspondence. Previously, the identification of SW insulators has been widely proposed for 2D phononic systems, but it has received little attention for 3D phononic systems. Herein, it is recognized that the 3D 3,44T19 type carbon allotrope (3,44T19‐CA) possesses the possibility to attain the nontrivial phononic SW topology characterized by a nontrivial second SW number, specifically w2 = 1. In addition, the 3D 3,44T19‐CA has 2D surface vibrational modes and 1D hinge vibrational modes, providing an excellent platform for multi–dimensional topological phononic boundaries research. [ABSTRACT FROM AUTHOR]

Discussions within queer time studies often hinge upon a simplistic binary division between Lee Edelman's anti-futurism and José Esteban Muñoz's queer utopianism. This article aims to reframe this discourse, acknowledging its limitations and proposing alternative approaches to conceptualizing the future through a queer lens. Beginning with a brief overview of both the queer anti-social thesis and future-oriented utopias, this article explores alternative, critical frameworks for future-making praxis such as Jussi Parikka's 'counter-futuring' and Bahar Noorizadeh's 'weird-futuring'. Leveraging these frameworks and Muñoz's suggestion to investigate novel queer epistemologies within queer art, the article then examines Zach Blas' 'xeno-telos' and micha cárdenas' 'queer prototyping', as paradigmatic examples of queer future-making beyond the referred dichotomy. In conclusion, this article argues for a diversification of queer time/future politics, advocating for partial, precarious and open-ended approaches to future-oriented thinking; approaches that embrace the unknown, trial and error and unexpected possibilities, thus fostering, new, diversified and radically engaged queer temporal politics. [ABSTRACT FROM AUTHOR]

The batter rock-socketed pile (BRSP) groups have been gradually introduced in practice to support not only the vertical load caused by overlying infrastructures but also the horizontal loads caused by waves and wind. A series of laboratory model tests were conducted to investigate the bearing capacities of the BRSP groups installed with their batter piles ranging from 0° to 20° under combined vertical and horizontal loads. It is found that the vertical ultimate bearing capacities nonlinearly increase with the increase of the batter angle with its optimum batter angle of 10°. The normalized vertical loads and horizontal ultimate loads are nonlinearly related to their relationship in an ellipse function. The plumb rock-socketed pile groups develop primarily a pair of shear forces and secondary bending moments due to the clockwise rotation under the pure horizontal loads. The BRSP group may fail due to the pile fracture near the pile cap in the form of the plastic hinge or compression failure at the base of the front pile. The corresponding load-displacement curves mostly have no peak or sudden downward trend. [ABSTRACT FROM AUTHOR]

This study presents a novel framework for the optimal design of compliant mechanisms, specifically addressing the structural drawbacks of conventional single-point or de facto hinges. The hinges often lead to structural instability and stress concentration while deriving maximum motion. To overcome these issues, we introduce a new method that can design stable and elastic domains connected by either revolute or prismatic joints. The new method, called sequential analysis based on the reaction force, can successfully eliminate weak hinge points while optimizing joint locations. The efficiency of developed methodology is validated through several numerical examples, yielding compliant mechanisms with suppressed hinges. [ABSTRACT FROM AUTHOR]

Experimental observations have revealed a change in the concavity of the resultant force-displacement plot in the extension test for pantographic sheets. In this paper, we aim to relate these macroscopically observed mechanical properties with the microscale properties of the hinges (or pivots) connecting the pantographic fibers. The material constituting the hinges is modeled at the microscale as an isotropic elastoplastic 3D Cauchy continuum. The elastic regime is assumed to be linear, while the plastic regime exhibits either saturating or non-saturating hardening. In the case of circular homogeneous cylindrical hinges, monotonic loading is considered to derive a mesoscale constitutive relation linking the torsional angle to the total applied torque. It is demonstrated that (non-)saturating hardening at the microscale results in (non-)saturating hardening of the twist angle/torque plot at the mesoscale, which itself is responsible for the change of concavity in bias extensional test of pantographic sheets. [ABSTRACT FROM AUTHOR]

During the swivel construction of a large-tonnage cable-stayed bridge, a single spherical hinge is susceptible to be damaged from excessive force. Consequently, this paper suggests a multi-point support swivel method of gear rails. The paper introduces a multi-point support swivel system of large-tonnage gear-tooth-rail, along with the swivel construction and monitoring technology. Models of the spherical hinge are established. Results indicate that the force applied to the spherical hinge is reasonable, exhibiting a gradual increase in contact stress from the center to the outer edges. The distribution of Mises stress differs from the distribution of contact stress. The force applied by the driving device is reasonable, ensuring the safety and feasibility of the proposed approach. The findings have guiding significance for future engineering. [ABSTRACT FROM AUTHOR]

The article presents the course and results of research aimed at assessing the strength and practical usability of a furniture hinge additively manufactured from thermoplastic material. The research activities included: development of design assumptions, adoption of target geometry, creation of a 3D-CAD model, preliminary strength analysis in the FEM environment, prototype manufacturing using FFF method with thermoplastic material (pet-g), and conducting tests under conditions similar to real ones. The hinge geometry was based on typical market-available design solutions, while considering the specifics of the adopted manufacturing method. Strength analysis via FEM was conducted on the 3D-CAD model, allowing estimation of stress values and determination of the suitability of the developed geometry for testing on a real model. Subsequently, research models were produced using FFF technology with various infill patterns: linear 30%, hexagonal 30%, linear 60%, hexagonal 60%, and solid 100%. Bench tests were conducted to determine the maximum load-bearing capacity of the hinge under perpendicular loading to the axis and to assess hinge wear under conditions simulating real-life door usage. The results revealed that the hinge with solid infill safely carried a load of 160 kg without damage, while the hinge with hexagonal 30% infill exhibited the lowest load-bearing capacity, failing at 85 kg. To determine the hinge's durability, the clearance at two reference points on the doors was measured. [ABSTRACT FROM AUTHOR]

Mandrel is an indispensable tool for manufacturing hollow curved components with large diameter by rotary draw bending. In this paper, an analytical model of mandrel parameters in numerical control (NC) rotary bending of a large diameter tube using a spherical hinge mandrel was proposed, and then the mandrel extension length and core number were preliminarily determined. A nonlinear 3D elastoplastic finite element (FE) model for simulating the NC rotary bending was established. The influences of mandrel-cores on the tangential stress, strain, and bending deformation characteristics were systematically studied. The results show that the maximum prediction errors of wall thicknesses and cross-section distortion are all less than 10%, and the simulated wrinkling position and number also showed good agreements with experimental ones, which indicate that the established FE model is accurate and reliable. Compared with the tube bending without mandrel-cores, the difference between maximum tangential tensile and compressive stresses, as well as the shift of stress and strain neutral layers, was smaller for tube bending with mandrel-cores, which had a good inhibitory effect on cross-section distortion and wrinkling. During tube bending with mandrel-cores, the compressive deformation zone was only located within the zone from the bending tangent point to the section position of 30°, and the tangential compressive strain reached peak value at the section position of 30°. Among the mandrel parameters, core number has a significant influence on cross-section distortion, while mandrel extension length is more sensitive to the wall thickness thinning. The cross-section distortion decreased while the wall thinning rate increased with increasing mandrel extension length, core number, and decreasing the clearance between mandrel and tube. A low friction between the mandrel and tube can decrease cross-section distortion and wall thinning rate. The appropriate mandrel extension length, core number, and clearance between mandrel and tube in NC rotary bending of ⌀ 76 × 1.2 × R150 mm tube were 9 mm, 3, and 0.2 mm, respectively. [ABSTRACT FROM AUTHOR]

To reduce in‐stent restenosis (ISR), caused by an elastic recoil stent at the initial bend of the artery, it is proposed to use stents with FG bridges, the bending stiffness of which depends on their location. The distribution of bending stiffnesses of FG bridges is studied depending on the initial bend of the artery. The bending of the FG cardiovascular stent is modeled by the bending of a beam with concentrated elastic hinges. Several methods of adapting the stent to the initial bending of the stented section of the vessel were considered: for bridges of the same stiffness, the functional of the squared difference between the deformation of the stent and the initial bending of the artery was minimized; for FG bridges, the flexural compliance of the stent is minimized. Problems are solved based on variational and homogenization approaches. An optimal scheme for the distribution of bending stiffnesses of FG bridges has been found. [ABSTRACT FROM AUTHOR]

We present a numerical framework bringing together a structural and a surface-energy minimization model to compute nano- and microorigami self-folding processes, that are three-dimensional in nature. A liquid drop, initially at rest on the template, triggers the spontaneous folding and deforms dynamically with the template. As application, the self-folding of thin two-dimensional templates into pyramidal microstructures is simulated. Each template is composed of a fixed regular base connected to rigid triangular side panels by two elastic hinges. We presently determine the condition, at which the transition from partial to full drop encapsulation occurs. The present model makes use of phase fields to numerically represent the drop and the template. This allows to: (i) develop an efficient computational method, which incorporates time-derivative terms and (ii) study three-dimensional complex self-folding processes. [ABSTRACT FROM AUTHOR]

To solve the problem of maximizing space utilization of car folding seats within limited spatial constraints, a design method for space-maximizing four-bar folding seat hinges is proposed. First, we will investigate the existing types of car folding seats, identify the mainstream configurations, and determine the optimal position of the four-bar linkage hinge point based on the constraints present within the car using theoretical analysis methods. Secondly, kinematic and dynamic models of the four-bar linkage mechanism are established, followed by the formulation of kinematic and dynamic equations. Finally, numerical methods are employed to solve these equations and obtain the kinematic and dynamic characteristics. The results indicate that the design method proposed in the article, which aims to maximize the space of the hinge four-bar folding seat, is efficient and feasible. This approach optimizes the utilization of interior space and enhances passenger comfort while accommodating the folding function of the seat within the existing vehicle environment. This method holds significant engineering implications for the design of folding seats in similar types of vehicles. [ABSTRACT FROM AUTHOR]

This study proposes a novel reduced beam section concrete‐filled double steel tube (RBS CFDST) beam‐to‐column joint and investigates the effect of RBS length and the beam moment of inertia on the plastic hinge formation in such joints. Therefore, a set of nine RBS CFDST connections were fabricated and cast with self‐consolidating concrete in the laboratory. Then, parameters including failure pattern, buckling mode, plastic hinge location, joint maximum load‐bearing capacity, and column rotation were inspected. The findings reveal that when the RBS length is equal to that of the beam dimension, the entire plastic hinge length is formed within the RBS zone. As such, the plastic hinge occurs away from the column face and brittle failure is avoided, while the joint column rotation is significantly reduced. It was also concluded that the maximum load‐bearing capacity is the highest when the RBS length is at its lowest. [ABSTRACT FROM AUTHOR]

To prevent the early breakage of anchor cables under shear loads in support engineering, a combined structure of Anchor Cable with C-shaped Tube (ACC) has been proposed. The shear resistance enhancement mechanism of this structure and the mechanisms of various influencing factors have yet to be fully revealed. A refined nonlinear finite element model of ACC was original established using ABAQUS software, taking into account the actual structure of the steel strands and the interactions, such as contact and failure between the various components. Various anchor cable pretension forces and block strengths were set to investigate their effects on the shear mechanical response of ACC. The results successfully demonstrated a high correlation between peak shear load and pretension force. The results demonstrate that an increase in pretension force reduces the ACC's peak shear load and break displacement. Additionally, the structure exhibited higher flexural stiffness, the block strength was mobilized earlier, and the block failed locally more quickly. Under high pretension forces, the system exhibited higher shear stiffness in the early stages of shearing due to the influence of the axial force component. With low pretension forces, the ACC exhibited a larger break displacement due to the minor tensile deformation at the shear plane position for the same shear displacement. At low pretension forces, the structure's bending angle increased more rapidly during the middle and later stages of shearing, accompanied by a larger break displacement. Both of these factors led to a greater bending angle at the shear plane position at the point of failure. The results reveal the characteristic of the peak shear load initially increasing and then decreasing with the increase in test block strength, along with its underlying mechanism. As the block strength increased, the bending angle of the structure at the shear plane position increased more rapidly, resulting in higher shear stiffness. With high block strength, the combination of smaller break displacement and greater shear stiffness led to an initial increase followed by a decrease in peak shear load. A comprehensive RSSB (Relative Stiffness between Structure and Test Block) that considers both structural and test block stiffness was proposed. The deformation pattern of the structure was controlled by the RSSB. The higher the RSSB, the wider the plastic hinge extension range for the same shear displacement, the smaller the bending angle at the shear plane position, and the smaller the maximum curvature of the structure. The contact force of the C-shaped tube generally exhibited a "single peak" distribution. As the shear displacement increased, the peak position of the contact force moved away from the shear plane, and the maximum contact force increased rapidly and remained relatively stable. At the end of the shearing process, the contact force of the C-shaped tube exhibited a "double peak" distribution. [ABSTRACT FROM AUTHOR]

The in-plane stability of internally hinged, end-fixed shallow arches is in the spotlight. The non-linear model accounts for the coupled effect of the bending moment and axial force on the membrane strain. The model itself can handle homogeneous or non-homogeneous material distributions along the thickness of the uniform arch. Analytical findings reveal how the typical geometrical data, like arch length, radius of gyration, and arch angle, affect the lowest buckling loads. The typical non-linear behaviour of arches is also assessed including the equilibrium path and the internal force system. [ABSTRACT FROM AUTHOR]

It is generally taken for granted that comparability in comparative research hinges, among others, on the quality of questionnaire translations. However, what do slight differences in translation mean for respondents' answers? In this article, we look at a combination of quantitative evidence from split-ballot experiments and qualitative evidence from additional probing questions for three items that were translated according to different translation methods, resulting in different translations, e.g., for "our national way of life." Two of the three items do not show any quantitative differences between translation versions when implemented in split-ballot experiments. However, using open-ended probing questions we delved deeper into the effects of different translation versions. This allowed us to show that different translations do indeed change respondent understanding. We suggest mechanisms that may lead to different translations (not) having an impact on the data, and we also try to align the results to the notion of equivalence/comparability in translation. Ultimately, we showcase the usefulness of web probing for exploring different translation understandings. [ABSTRACT FROM AUTHOR]

Much of our understanding of the history of life hinges upon time calibration, the process of assigning absolute times to cladogenetic events. Bayesian approaches to time‐scaling phylogenetic trees have dramatically grown in complexity, and depend today upon numerous methodological choices. Arriving at objective justifications for all of these is difficult and time‐consuming. Thus, divergence times are routinely inferred under only one or a handful of parametric conditions, often times chosen arbitrarily. Progress towards building robust biological timescales necessitates the development of better methods to visualize and quantify the sensitivity of results to these decisions.Here, we present an R package that assists in this endeavour through the use of chronospaces, that is, graphical representations summarizing variation in the node ages contained in time‐calibrated trees. We further test this approach by estimating divergence times for three empirical datasets—spanning widely differing evolutionary timeframes—using the software PhyloBayes.Our results reveal large differences in the impact of many common methodological decisions, with the choice of clock (uncorrelated vs autocorrelated) and loci having strong effects on inferred ages. Other decisions have comparatively minor consequences, including the use of the computationally intensive site‐heterogeneous model CAT‐GTR, whose effect might only be discernible for exceedingly old divergences (e.g. the deepest eukaryote nodes).The package chronospace implements a range of graphical and analytical tools that assist in the exploration of sensitivity and the prioritization of computational resources in the inference of divergence times. [ABSTRACT FROM AUTHOR]

Bamboo beams are often reinforced with built-in steel sections to enhance their strength and load-bearing capacity. In this paper, we studied the effect of different parameters, including the location of the hole, the hole size, and the thicknesses of the steel and bamboo, on the mechanical properties of reinforced beams. The damage patterns, deformation characteristics, and force-transfer mechanisms, as well as the mechanical properties of reinforced beams with different hole shapes, underwent non-linear finite element analysis. The damage sustained by the reinforced bamboo beam differed from that of the traditional bamboo beam; two diagonal points formed a plastic hinge, mainly during the process of shear damage to the hole. It was determined that the hole size and the thickness of the bamboo have the greatest influence on the mechanical properties of the reinforced beam. The damage characteristics of the composited beams with different holes are similar; the bearing capacity of reinforced beams with open square holes is reduced by 10%–25%compared with circular holes. [ABSTRACT FROM AUTHOR]

A perfectly auxetic 2D metamaterial model is described herein by means of interconnected rotating rigid units of three different shapes: hexagons, triangles, and rectangles. The in‐plane Young's modulus is obtained by matching the discrete elastic energy stored at the hinges during relative rotation of the rigid units with the overall elastic energy stored in the metamaterial's continuum equivalence. Results indicate that, in addition to the trivial effects from the rotational spring constant at the hinges, the in‐plane Young's modulus is highly influenced by the internal angle, followed by the relative size of the triangle with reference to the sizes of other rigid units. The effect from the rectangle aspect ratio presents the least influence. As such, there are several parameters to control the Young's modulus, from the coarse tuning by adjusting the internal angle to fine tuning by controlling the rectangle aspect ratio. The capability of the metamaterial's Young's modulus to be tuned from a spectrum of parameters that range from coarse to fine tuning permits this metamaterial's mechanical property to be precisely designed and manufactured in a cost‐effective manner. [ABSTRACT FROM AUTHOR]

ABSTRACT The innovative use of real‐world data (RWD) can answer questions that cannot be addressed using data from randomized clinical trials (RCTs). While the sponsors of RCTs have a central database containing all individual patient data (IPD) collected from trials, analysts of RWD face a challenge: regulations on patient privacy make access to IPD from all regions logistically prohibitive. In this research, we propose a double inverse probability weighting (DIPW) approach for the analysis sponsor to estimate the population average treatment effect (PATE) for a target population without the need to access IPD. One probability weighting is for achieving comparable distributions in confounders across treatment groups; another probability weighting is for generalizing the result from a subpopulation of patients who have data on the endpoint to the whole target population. The likelihood expressions for propensity scores and the DIPW estimator of the PATE can be written to only rely on regional summary statistics that do not require IPD. Our approach hinges upon the positivity and conditional independency assumptions, prerequisites to most RWD analysis approaches. Simulations are conducted to compare the performances of the proposed method against a modified meta‐analysis and a regular meta‐analysis. [ABSTRACT FROM AUTHOR]

We consider fertile three-state Hard-Core (HC) models on a Cayley tree. It is known that there exist four types of such models: 'wrench', 'wand', 'hinge' and 'pipe'. In cases 'wand' and 'hinge' on a Cayley tree of arbitrary order a complete description of translation-invariant Gibbs measures is obtained. The concept of alternative Gibbs measure is introduced and in the case 'wand' translational invariance conditions for alternative Gibbs measures are found. Also, we show the existence of alternative Gibbs measures which are not translation-invariant. [ABSTRACT FROM AUTHOR]

As a novel learning algorithm for feedforward neural networks, the twin extreme learning machine (TELM) boasts advantages such as simple structure, few parameters, low complexity, and excellent generalization performance. However, it employs the squared L 2 -norm metric and an unbounded hinge loss function, which tends to overstate the influence of outliers and subsequently diminishes the robustness of the model. To address this issue, scholars have proposed the bounded capped L 2 , p -norm metric, which can be flexibly adjusted by varying the p value to adapt to different data and reduce the impact of noise. Therefore, we substitute the metric in the TELM with the capped L 2 , p -norm metric in this paper. Furthermore, we propose a bounded, smooth, symmetric, and noise-insensitive squared fractional loss (SF-loss) function to replace the hinge loss function in the TELM. Additionally, the TELM neglects statistical information in the data; thus, we incorporate the Fisher regularization term into our model to fully exploit the statistical characteristics of the data. Drawing upon these merits, a squared fractional loss-based robust supervised twin extreme learning machine (SF-RSTELM) model is proposed by integrating the capped L 2 , p -norm metric, SF-loss, and Fisher regularization term. The model shows significant effectiveness in decreasing the impacts of noise and outliers. However, the proposed model's non-convexity poses a formidable challenge in the realm of optimization. We use an efficient iterative algorithm to solve it based on the concave-convex procedure (CCCP) algorithm and demonstrate the convergence of the proposed algorithm. Finally, to verify the algorithm's effectiveness, we conduct experiments on artificial datasets, UCI datasets, image datasets, and NDC large datasets. The experimental results show that our model is able to achieve higher ACC and F 1 scores across most datasets, with improvements ranging from 0.28% to 4.5% compared to other state-of-the-art algorithms. [ABSTRACT FROM AUTHOR]

Bending active structures involve the deformation of originally flat structures during the erection process. These structures offer a promising approach to enhance design sustainability. However, despite advancements in structural computational methods, their implementation is still limited. This paper examines the constraints associated with this design approach from a designer's perspective and proposes potential solutions. From this analysis, a design method is developed that utilizes additive manufacturing to explore different solutions during the concept stage. Prior to the form-finding process, a flat, variable-density pattern is created within a parametric environment. This pattern, referred to as the "Soft Pattern based on Control Points" (SPSCP), incorporates multiple design variables to accommodate diverse design requirements. In this preliminary study, we compare the impact of varying the design parameters on a small-scale model, as observed by the naked eye, and through finite element analysis. [ABSTRACT FROM AUTHOR]

Within an industrial plant, the handling of randomly arranged objects is becoming increasingly popular. The technology industry has introduced ever more powerful devices to the market, but they are often unable to meet the demands of the industry in terms of processing times. Using a multi-component feeder, which facilitates the automatic picking of objects arranged in bulk, is the ideal element to speed up the identification of objects by the vision system. The innovative designed feeder eliminates the dead time of the vision system since the feeder has two working surfaces, thus making the viewing time hidden in relation to the total handling cycle time. In addition, the step feeder integrated into the feeder structure allows for control over the number of objects that fall onto the work surface, optimizing the material flow. The feeder was designed to palletize aluminum hinge fins but can also handle other products with different shapes and sizes. A two-dimensional (2D) vision system is integrated into the robotic cell to identify the components to be palletized, obtaining a reduced cycle time. The innovative feeder is fully adaptable to industrial applications and allows for easy integration into the robotic cell in which it is installed; by testing its operation with different aluminum fins, male and female, significant results were obtained in terms of cycle times ranging from 1.44 s to 1.68 s per piece, with an average productivity level (PL) of 1175 pcs every 30 min. [ABSTRACT FROM AUTHOR]

Morphing airplane technology is currently a focal point of research. For morphing airplanes, besides effective morphing strategies and control schemes, the hinge moment at the root of the vertical tail during morphing is a critical factor influencing flight safety. To prevent failure in tail morphing due to excessive hinge moments, this paper analyzes the hinge moment characteristics of the variable vertical tail structure in high-speed flight, based on a flying wing model from the China Aerodynamics Research and Development Center. The proposed adaptive morphing tail hinge moment reduction (AMTHR) method is model-free, utilizing real-time data to dynamically adjust the rudder and reduce hinge moments without requiring prior knowledge of system dynamics. This method utilizes the concept of extremum-seeking control by introducing periodic perturbations to the system and adjusting the control input based on their impact on the output. This approach drives the output toward an extremum point, enabling real-time reduction of the vertical tail hinge moment. Finally, the simulation analysis is carried out under the conditions of no wind and gust disturbance, and the effect of this method on the load reduction of the tail hinge moment is verified. [ABSTRACT FROM AUTHOR]

To improve the vibration performance of oil-lubricated tilting pad bearing systems, this paper investigates the impact of different structural parameters on the vibration reduction effect of piezoelectric actuators on flexible tilting pad bearings. Four sets of flexible tilting pad bearings were designed and manufactured, including a flexible hinge tilting pad bearing and three sets of double-layer spring-supported flexible tilting pad bearings with different parameters. The radial displacement of the bearing load pad was controlled to varying degrees using a piezoelectric actuator, and semi-active control experiments were conducted on the flexible tilting pad bearings. The experimental results show that appropriately reducing the radial clearance and the stiffness of the bearing's flexible structure can effectively suppress vibrations, enhance the vibration reduction effect of the piezoelectric actuation, and increase the stability of the bearing-rotor system. This study is of significant importance for the design of flexible tilting pad bearings and the vibration suppression of rotor systems. [ABSTRACT FROM AUTHOR]

A high-precision focusing mechanism was designed using a flexible hinge to address the demand for precise focusing in space cameras. Firstly, a finite element model of the liner guideway was created using Hertz contact theory, and the accuracy of the model was confirmed using the "flip method". Subsequently, the flexible hinge was optimized by a mix of topological and integrated optimization. The simulation results demonstrated that the improved flexible hinge successfully eliminates interference between the liner guideway and the screw, minimizes the effects of initial assembly mistakes, and greatly reduces the tilt error of the focusing mechanism. Afterward, the focusing mechanism was subjected to a vibration test, which showed that its first-order fundamental frequency reached 163.28 Hz. This frequency is sufficiently high to minimize the risk of resonance during the launch phase. Ultimately, the tilt error of the focusing mechanism was assessed using both a rigid connector and a flexible hinge. The findings demonstrated that implementing the flexible hinge resulted in a 55.7% decrease in the range of Δθz and a 55.22% reduction in the standard deviation, effectively fulfilling the specified design requirements. This study indicates that the inclusion of a flexible hinge in the focusing mechanism leads to a substantial decrease in tilt error. [ABSTRACT FROM AUTHOR]

This paper describes the design and experimental verification of a 6 m parabolic deployable mesh reflector antenna mechanism based on a superelastic shape memory alloy. This antenna mainly consists of a deployable primary reflector with a superelastic shape memory alloy-based hinge mechanism and a fixed-type secondary reflector mast, where a rotary-type holding and release mechanism and deployment speed control system are installed. The main feature of this antenna is the application of a superelastic shape memory alloy to the mechanism, which has the advantages of plastic deformation resistance, high damping, and fatigue resistance. A shape memory alloy is applied to the hinge mechanism of each primary reflector rib and to the rotary-type holding and release mechanism as a deployment mechanism. In addition, a superelastic shape memory alloy wire is applied to the antenna in the circumferential direction to maintain the curvature of the primary reflector. The effectiveness of the proposed mechanism design was verified through repeated deployment tests on models of the superelastic shape memory alloy-based hinge mechanism and the antenna system. [ABSTRACT FROM AUTHOR]

This paper proposes a novel estimator for support vector machines with matrix-valued covariates in a high-dimensional setting. We assume that the underlying parameter matrix lies in a low-dimensional subspace that is simultaneously low-rank and row (column) sparse. We formulate the problem as a regularized hinge loss minimization problem using the nuclear and group lasso norms as penalties to exploit the low-dimensional structure. Our primary focus is deriving the statistical convergence rate of the regularized estimator for the unknown parameter matrix. To validate our theoretical findings, we conducted numerical experiments on both simulated and real-world datasets, demonstrating the efficacy of the regularized support matrix machines framework. [ABSTRACT FROM AUTHOR]

This research aims to develop and validate a fiber Bragg grating (FBG) accelerometer, designed with a bearing and flexure hinge structure, to accurately measure medium‐ and high‐frequency vibrations caused by wheel‐rail excitation. The structural parameters of the accelerometer are optimized through theoretical mechanics analysis, and its dynamic characteristics are verified by experimental vibration testing and compared with the finite element simulated results. Key findings reveal that the proposed sensor has a wide operational frequency range of 10–1200 Hz and a high acceleration sensitivity of 3 pm/m·s−2, in addition to excellent linearity and repeatability. Moreover, the sensor demonstrates immunity to temperature variations, making it suitable for use in fluctuating temperature environments. Laboratory model experiment tests of high‐speed train tracks show that the FBG accelerometer effectively identifies medium‐ to high‐frequency vibration signals caused by wheel‐rail excitation, corroborated by traditional piezoelectric accelerometers. The results confirm the sensor's ability to capture vertical axle box vibration acceleration (ABVA) and its potential for assessing axle box structural dynamics in high‐speed railway applications. [ABSTRACT FROM AUTHOR]

Translocation in protein synthesis entails the efficient and accurate movement of the mRNA-[tRNA]2 substrate through the ribosome after peptide bond formation. An essential conformational change during this process is the swiveling of the small subunit head domain about two rRNA 'hinge' elements. Using iterative selection and molecular dynamics simulations, we derive alternate hinge elements capable of translocation in vitro and in vivo and describe their effects on the conformational trajectory of the EF-G-bound, translocating ribosome. In these alternate conformational pathways, we observe a diversity of swivel kinetics, hinge motions, three-dimensional head domain trajectories and tRNA dynamics. By finding alternate conformational pathways of translocation, we identify motions and intermediates that are essential or malleable in this process. These findings highlight the plasticity of protein synthesis and provide a more thorough understanding of the available sequence and conformational landscape of a central biological process. Author summary: Translocation, the motion of the ribosome across its mRNA substrate, is an essential stage of protein synthesis. A key conformational change in this process is the rotation of the ribosome head domain about two rRNA hinges in the direction of translocation, repositioning the mRNA and tRNAs in their final states. Employing iterative selection, we obtain variant hinges capable of performing translocation in vitro and in vivo. Through molecular dynamics simulations, the different variant ribosome translocation conformational trajectories are described. This description reveals different possible conformational pathways to translocation, with varying dynamics, motions and intermediates. The understanding of this conformational malleability can increase our knowledge of protein synthesis function, disruption, evolution, and engineering. [ABSTRACT FROM AUTHOR]

Environmentally fueled sustainable autonomous locomotion is an advanced intelligent behavior analogous to unconscious actions in biological organisms, such as heartbeat and peristalsis. In this study, a self‐sustaining oscillating soft robot is introduced with eccentric hinge structures inspired by the crawling locomotion of mollusks. A parameter‐encoded 4D printing method is utilized to pre‐program local strain of the eccentric hinge structure, and thus endows the soft robot with sustainable crawling motions under constant thermal field. Through the coupling design of substrate friction, eccentric hinge constitution, and the substrate temperature, the soft robot can achieve tunable crawling, rolling, and oscillating. Two applications, namely an optical chopper and a power generator are presented as proof of concepts. This work offers a viable solution for soft robots for applications in constrained environments such as the aerospace and medical fields. [ABSTRACT FROM AUTHOR]

This article presents a generalized model of two-axis flexure hinges based on quadratic rational Bézier curve. The generalized closed-form compliance equations are derived based on the virtual work theory and the superposition relationship of the deformation. Then, how to determine the number of sensitive axes, the location of the primary and secondary sensitive axes, and the configuration of the notch profile are discussed. There are 20 types of notch profiles derived from single or mixed, symmetrical or asymmetrical curves. And, the correctness of the compliance equations is verified by finite-element analysis. The maximum relative error does not exceed 10%. Finally, the precision of rotation, the maximum stress, and the effect of structural parameters on the compliance are analyzed. The results show that for two-axis flexure hinges with a flush single curve notch profile, the proximity of the center of rotation to the load end does not significantly affect the axial compliance as well as the torsional compliance. For hybrid two-axis flexure hinges with symmetric structure, the ability to maintain the center of rotation under lateral forces is better than that under the same torque. The proposed generalized model provides a reference for the design of spatial compliant mechanisms. [ABSTRACT FROM AUTHOR]

To enhance the functionality of a constant-torque flexure hinge (CTFH), a bidirectional double-arc constant-torque flexure hinge (BD-CTFH) is proposed. The BD-CTFH exhibits characteristics such as a bidirectional constant-torque output and sufficient proportion of constant-torque output. The primary objective of this study is to establish a pseudo-rigid-body model of the BD-CTFH (BD-PRBM) to accurately determine the constant-torque output performance. In addition, a comprehensive analysis of the torque-angle characteristics of the BD-CTFH is conducted through finite element analysis (FEA), theoretical calculations, and experimental testing. The results indicate that the discrepancy between the theoretical and FEA results is within 2 %, confirming the accuracy of the BD-PRBM. Moreover, the average deviation between the experimental and theoretical results is within 5 %, further validating its accuracy. Finally, through preloading tests, it is verified that the BD-CTFH exhibits a constant-torque region of 12–36° (and -12–-36°). • The novel flexure hinge (BD-CTFH) incorporates double-arc segments for the first time. • The BD-CTFH has the characteristic of bidirectional constant-torque output. • The PRBM of BD-CTFH (BD-PRBM) is established. • Preload of BD-CTFH is carried out to enlarge the proportion of constant-torque. [ABSTRACT FROM AUTHOR]

Innovative designs such as morphing wings and terrain adaptive landing systems are examples of biomimicry and innovations inspired by nature, which are actively being investigated by aerospace designers. Morphing wing designs based on Variable Geometry Truss Manipulators (VGTMs) and articulated helicopter robotic landing gear (RLG) have drawn a great deal of attention from industry. Compliant mechanisms have become increasingly popular due to their advantages over conventional rigid-body systems, and the research team led by the second author at Toronto Metropolitan University (TMU) has set their long-term goal to be exploiting these systems in the above aerospace applications. To gain a deeper insight into the design and optimization of compliant mechanisms and their potential application as alternatives to VGTM and RLG systems, this study conducted a thorough analysis of the design of flexible hinges, and single-, four-, and multi-bar configurations as a part of more complex, flexible mechanisms. The investigation highlighted the flexibility and compliance of mechanisms incorporating circular flexure hinges (CFHs), showcasing their capacity to withstand forces and moments. Despite a discrepancy between the results obtained from previously published Pseudo-Rigid-Body Model (PRBM) equations and FEM-based analyses, the mechanisms exhibited predictable linear behavior and acceptable fatigue testing results, affirming their suitability for diverse applications. While including additional linkages perpendicular to the applied force direction in a compliant mechanism with N vertical linkages led to improved factors of safety, the associated increase in system weight necessitates careful consideration. It is shown herein that, in this case, adding one vertical bar increased the safety factor by 100 N percent. The present study also addressed solutions for the precise modeling of CFHs through the derivation of an empirical polynomial torsional stiffness/compliance equation related to geometric dimensions and material properties. The effectiveness of the presented empirical polynomial compliance equation was validated against FEA results, revealing a generally accurate prediction with an average error of 1.74%. It is expected that the present investigation will open new avenues to higher precision in the design of CFHs, ensuring reliability and efficiency in various practical applications, and enhancing the optimization design of compliant mechanisms comprised of such hinges. A specific focus was put on ABS plastic and aluminum alloy 7075, as they are the materials of choice for non-load-bearing and load-bearing structural components, respectively. [ABSTRACT FROM AUTHOR]

In this paper, we study the Γ -limit of a properly rescaled family of energies, defined on a narrow strip, as the width of the strip tends to zero. The limit energy is one-dimensional and is able to capture (and penalize) concentrations of the midline curvature. At the best of our knowledge, it is the first paper in the Γ -convergence field for dimension reduction that predicts elastic hinges. In particular, starting from a purely elastic shell model with "smooth" solutions, we obtain a beam model where the derivatives of the displacement and/or of the rotation fields may have jump discontinuities. Mechanically speaking, elastic hinges can occur in the beam. [ABSTRACT FROM AUTHOR]

This study investigates the vibration energy flow transmission behavior of laminated composite plate structures coupled with a line hinge. The time-averaged vibration energy transfer is determined using the substructure-based power flow analysis (SPFA) method. The effects of the fiber orientation, boundary conditions and the position of the coupling hinge on the vibration transmission path and its level are examined. It is demonstrated that the fiber orientations can be used to modify substantially the power flow transmission path and locations of energy sinks. Enhancement of vibration suppression of the coupled structure can be achieved by tailor designing the fiber angles. [ABSTRACT FROM AUTHOR]

Purpose: Derotational distal femoral osteotomy (DFO) is the causal treatment for patients with femoral torsional deformity. The fixation is achieved by a unilateral angle‐stable plate. Delayed‐ or non‐unions are one of the main risks of the procedure. An additional contralateral fixation may benefit the outcome. Therefore, we hypothesize that primary stability in DFO can be improved by an additional fixation with a hinge screw or an internal plate. Methods: Derotational DFO was performed in 15 knees and fixed either with an angle‐stable plate only (group 'None'), with an additional lateral screw (group 'Screw') or with an additional lateral plate (group 'Plate'). Biomechanical evaluation was carried out under axial loading of 150 N (partial weight bearing) and 800 N (full weight bearing), followed by internal and external rotation. After linear axial loading in step 1, a cyclic torsional load of 5 Nm was applied under constant axial load in step 2. In step 3, the specimens were unloaded. Micromovements between the distal and proximal parts of the osteotomy were recorded at each step for all specimens. Results: In step 1, the extent of micromovements was highest in group 'None' and lowest in group 'Plate' without being significantly different. In step 2, group 'Plate' showed significantly higher stability, reflected by less rotation and lower micromovements. Increasing the axial load from 150 to 800 N at step 2 resulted in increased stability in all groups but only reached significance in group 'None'. Conclusion: An additional contralateral plate significantly increased stability in derotational DFO compared to the unilateral angle‐stable plate only. Contrary, a contralateral hinge screw did not provide improved stability. Study Design: Experimental study. Level of Evidence: IV. [ABSTRACT FROM AUTHOR]

This research investigates the determination method, spreading mechanism and influencing factors of the plastic hinge length for asymmetrical flanged walls using the finite element method. The plastic hinge length of flanged walls under flange-in-compression loading is generally greater than that under flange-in-tension loading. Based on the results, simple equations for predicting the plastic hinge length of flanged walls and which consider the contributions of the moment gradient, diagonal shear cracks, and strain penetration are proposed. Through comparison with the existing equations and design codes, the predicted plastic hinge lengths obtained from the proposed equations accord better with the test results. [ABSTRACT FROM AUTHOR]

In this study, theoretical and numerical methods were used to research seismic shear distributions of frame-shear wall structures under elasto-plastic conditions. The shear distributions of frame-shear walls were analyzed based on a simplified elasto-plastic analysis model of flexural shear. Based on a preliminary project, three groups of 2D models with different stiffness eigenvalues were designed and used to compare the shear distributions of whole structures and frames. The characteristics of the shear distributions of structures and frames and the development of plastic hinges were analyzed, and the rationality of shear adjustment based on Chinese standards was discussed from the perspectives of structural design, seismic performance and collapse resistance. The results revealed obvious differences between shear distributions of structures caused by strong vs. frequent earthquakes. For strong earthquakes, the shear distributions tended to be evenly distributed with respect to height, while the shear force of the bottom story was significantly larger than that of the upper stories. This was mainly caused by the redistribution of plastic internal forces due to the development of plastic hinges. The shear adjustment of the frame usually affected the reinforcement in the beams rather than in the columns, which contradicted the design concept of strong columns – weak beams. Additionally, shear adjustment had little effect on the seismic performance and collapse resistance of structures. This paper suggests that by ensuring the ability of strong columns, weak beams and plastic hinges to rotate, shear force adjustment can be prevented. [ABSTRACT FROM AUTHOR]

Reusing existing CAD part models in product development can significantly shorten design time and reduce costs. However, due to the extensive number of existing CAD part models within the Product Data Management (PDM) system, designers often spend a considerable amount of time retrieving models that meet their specific requirements. This study introduces a method to retrieve parts that comply with design specifications using a relational design rule-embedded bill of materials (BOM). Parameters are extracted from CAD part models in the database to generate a list of parts with properties. The compliance of each part with the design specifications is verified utilizing the relational design rule-embedded BOM, and CAD part models meeting the specifications are identified and retrieved. To validate this approach, an experiment was conducted to retrieve CAD part models needed for designing a hinge assembly center of a refrigerator. The experiment successfully retrieved 24 CAD part models that complied with design specifications out of a total of 139 CAD part models from six different part types. Notably, this retrieval process was completed within 1 min and 45 s. [ABSTRACT FROM AUTHOR]

A column is a critical member in a reinforced concrete framed building. It transfers lateral shear during an earthquake, in the presence of gravity loads. Failure of short wall-type shear-critical columns in the soft and weak open ground story (OGS) of a building during an earthquake can trigger pancake-type collapse. To avoid these types of failures, the weak columns in the OGS can be strengthened locally, in addition to a global retrofit strategy applied to the entire structure. This research focuses on the seismic strengthening of such short columns using the concrete jacketing technique. The study presented in this paper demonstrates a methodology to model the shear behavior of short columns before and after jacketing. This pertains to the nonlinear static analysis of a building under lateral loads, such as a static pushover analysis. The development of shear hinge properties for as-built and jacketed short columns is presented in this paper. These were based on a proposed generalized truss analogy, which was validated based on the tests of column specimens conducted as part of this research. Pushover analyses of a building model without and with jacketed columns in the OGS were conducted. Selected results of the analyses are presented in this paper. The modeling of the shear hinge properties for the short columns in the OGS demonstrated the brittle behavior under lateral loads before jacketing and the improvement in ductility after jacketing. The proposed method can be used in professional practice for evaluating buildings with short columns strengthened by concrete jacketing. Since all the columns in a story cannot be jacketed due to economic and functional considerations, the effect of selective jacketing of the columns on the behavior of the building under lateral loads is illustrated. Practical Applications: An existing reinforced concrete framed building can be retrofitted to mitigate the damage expected during a future earthquake. The effect of retrofit on the structure should be justified preferably by a nonlinear method of analysis such as pushover analysis. The primary input in such an analysis is the nonlinear behavior of each structural member under increasing lateral loads, modeled as the hinge property. The presented study discusses the pushover analyses of a building, before and after strengthening its short wall-type columns in the open ground story by concrete jacketing. A method to develop the shear hinge properties of as-built and jacketed short columns is explained in this paper. The method is based on extending the truss analogy for modeling the shear deformation of a short frame member after the diagonal cracking of concrete in the web. The procedure does not need any special purpose program for calculation and can be implemented using a spreadsheet. Also, a parametric study on optimum strengthening is presented, showing the effect of jacketing selected columns, as all the columns need not be intervened, to reduce the cost as well as the disruption to the users. [ABSTRACT FROM AUTHOR]

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As the most prevalent element on our planet, carbon manifests a wide variety of allotropic phases, significantly contributing to its complex physical properties. Recently, several carbon allotropes have been reported to possess abundant topological phases in theory and experiment. This work focuses on a sp3 carbon allotrope, Z-ACA allotrope, which consists of 5-6-7-type Z-ACA carbon rings. This allotrope has been reported previously as a superhard material comparable to diamond. In this study, we report that it is a candidate for both an obstructed atomic insulator and a real Chern insulator. It is worth mentioning that Z-ACA exhibits an unconventional bulk-boundary correspondence due to its hinge boundary state manifestation. Our current research indicates that Z-ACA is a suitable carbon phase platform for studying the real topology and second-order bulk-boundary correspondence. [ABSTRACT FROM AUTHOR]