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This review reports the outcome of an research experimental on flexural behaviour of partially strengthened reinforced concrete beams along with Engineered Cementitious Composite (ECC). 6 beams were moulded and examined in total. Three beams were tested to determine the influence of plastic hinge length, whereas two beams were examined to determine the effect of large layers of ECC in the tension zone. The remaining beam acted as control beam. Along with beam specimens, cylinders and cubes were tested to evaluate the mechanical characteristics of both ECC and concrete. All the beams are strengthened using ECC plastic hinges and layers. And they could withstand maximum load than the regulate beams. Load capacities of reinforced concrete (RC) beams strengthened with ECC plastic hinges were 2.85 – 6.34 times more than those of the corresponding control beams. Similarly, RC beams having load capacities 5.71–8.45 times with ECC layers were even better. In general, ECC application increased the ductility of Reinforced concrete beams.

The origami principle of folding planar sheets into functional three-dimensional devices promises a future with increased compactness and reconfigurability of biomedical robots. To inspire new origami-based biomedical robots, we highlight two categories of origami patterns that are applicable to build compact actuators, deployable stents, and minimally invasive surgery devices. Due to the requirements in system integration, biocompatibility, and payload capability, the conventional paper-based origamis are converted to physical robots by replacing the zero-thickness facets and zero-width folds with thick panels and flexible hinges, respectively. Therefore, the physical origami-based robots become inhomogeneous, making it more complex and challenging to analyze their mechanics. So far, no such model can analyze the mechanics of any physical origami robot. Herein, we propose a computational model that discretizes the continuous structures into truss and spring elements to fulfill this goal. Based on the model, we simulate the identified origami structures under various boundary conditions to investigate their application in biomedical scenarios. This article is expected to accelerate the design iteration of new functional biomedical origami robots.

Back-rotation and hinges were detected in in situ piles during lateral spreading, but they were not reported in model tests. This paper presents, for the first time, model tests on vertically loaded capped piles subjected to pulse-like soil movement. The study reveals (i) modes of pile–soil interaction, including sway at a sliding depth (SD) of 0.286l (l = pile embedment), back-rotation at SD = 0.57l and sliding of the piles at either SD; (ii) the evolution rule of yielding moments at the ground level (Moy) and maximum bending moment (Mm) of the pile body for each mode. Expressions are synthesised from the tests to estimate Mm, to define the ultimate state as a rotation angle exceeding 0.8–1.2 times that of free-head piles, to gain limiting soil movement wf* (that incurs hinges) and residual displacement of piles. The simple expressions offer a good estimation of limiting soil movement and permanent displacement for the piles underpinning bridges in Christchurch, New Zealand. They are useful to complement the three-layer modelling of the response of piles incurred by sliding, sway and back-rotation.

The morphing wing has a significant positive effect on the aerodynamic performance of the aircraft. This paper describes a leading-edge of variable camber wing with concentrated flexibility based on the geared five-bar mechanism. The driving points of morphing skin formed by the glass fibre composite sheet were optimized to make the skin deformation smooth. A geared five-bar kinematic mechanism rigidly connected to the skin was proposed to drive the leading-edge deformation. Besides, a new kind of concentrated flexure hinge was designed using the pseudo-rigid-body method and applied to the joint between the rigid mechanism and the skin. Finally, the leading-edge prototypes with traditional hinges and flexure hinges were produced, respectively. The feasibility of the concentrated flexibility leading-edge was verified through the comparative experiments of ground deformation. Simultaneously, aerodynamic analysis was carried out to compare the concentrated flexure leading-edge wing with the original airfoil.

Robotic hand exoskeletons can assist people who suffer from hand functional disabilities caused by a stroke. However, currently existing hand exoskeletons remain inadequate in terms of user-friendly design, lightweight structure, and accurate modeling of hand motion. In this study, a large displacement compliant mechanism is developed as a finger exoskeleton. First, a topology configuration is developed which contains information on hand biomechanics and thus yields an efficient force-deflection mechanism for a finger. A pseudo-rigid-body model is then established using a large-deformation flexible hinge to solve the point flexure problem to create a finger exoskeleton that functions as intended. Finally, the mechanism synthesis method is used for parameter optimization to ensure that the output port of the device matches the motion of the finger. Using the proposed method, an integrated compliant finger exoskeleton is developed, and the performance of the exoskeleton is evaluated. The experimental result shows that the finger exoskeleton prototype provides suitable movement guidance for the index finger, which demonstrates that the proposed method may be a good way in the design of hand exoskeletons.

Self-actuated deployable space structures present a novel challenge for deployment dynamics modeling efforts, where the system-level influence of strain energy components must be captured. Here, th...

R-factor (Response reduction factor) is an important design consideration in seismic design of structures, which is assumed to consider energy dissipation of structures by means of ductility. So, proper estimation of R-factor is required for seismic design of structures which will account for ductile deformation so that suitable detailing of reinforcement can be done. In case of irregular structures, where the torsion effect is the predominant factor, accurate estimation of R-factor is even more difficult. Therefore, in the present study, an attempt has been taken to determine R-factor for plan irregular buildings. A G +7 storied building is considered and irregularity effect has been incorporated by C and L-shaped configuration. The design of the buildings has been done following Indian Standards. Modeling and analysis have been done using SAP2000. Plastic hinges have been considered to represent material nonlinearity. Mander’s confinement model has been considered. Nonlinear Static (Pushover) following FEMA 440 methods with uniform lateral load variations has been done. Initial tangent stiffness has been followed in equal area method during bi-linearization of pushover curve. It can be stated that apart from material strength and geometrical configuration, performance requirement of the buildings is the most important factor for selection of R-factor.

We propose and develop a high-sensitivity fiber Bragg grating (FBG) accelerometer based on a flexible hinge for vibration sensing. The proposed method employs a 1 mm FBG that is inscribed pointwise using a femtosecond laser such that the resultant stress concentration at the FBG is improved significantly by reducing the distance between the two bonding points of the FBG structure. Through theoretical calculations and finite element simulations, the relationship between sensitivity and distance was found to be inversely proportional. Using this structure, the sensitivity was enhanced to 804 pm/g at 15 Hz and 30 Hz. The resonant frequency of the proposed accelerometer is 102 Hz, and the working frequency bandwidth is from 10 to 50 Hz. The performance of the accelerometer allows detection of vibrations in seismic explorations with high reliability.

The interest in the use of laminated bamboo lumber (LBL) as a new green building material is growing rapidly, but little work has been conducted on the cyclic response of LBL nailed connection, which consists of LBL middle member sandwiched between two LBL plates. Experiments on 90 LBL-to-LBL nailed connections are done to study the effect of nail diameter and loading direction to the grain on cyclic behavior of the connections. It is found that the failure mode of the connections loaded monotonically is due to the formation of two hinges of nail, which is quite different from the connections loaded cyclically. Two plastic hinges are also observed in nails during the cyclic tests, in addition, most of the nails in connections fail in low cycle fatigue fracture due to reversed bending of nails. The load-carrying capacity, stiffness, and energy-dissipating capacity of the connections can be significantly improved by using larger-diameter nails as connectors, while decreases slightly with the increase of loading direction to grain. Regarding to the displacement ductility ratio, whether monotonic loading or cyclic loading, the connections show low ductility performance. The equivalent viscous damping coefficient decreases with the increase of the nail diameter, and not relates with the loading direction to the grain. The load-slip response of the LBL nailed joints exhibits pinched hysteretic behavior with strength and stiffness degradation under cyclic loading. The modified Dolan theoretical model can be used to predict the cyclic response of the LBL nailed connections.

Flight simulators have been used for a long time to train pilots of any type of aircraft. This type of training is more economical. The flight simulator improves control skills in extreme situations with minimal risks for the future pilot. Training on a flight simulator makes it possible to reproduce adverse weather conditions at any time. The pilot is on the ground in a special cockpit, which is mounted on a movable platform. This system is needed to ensure flight conditions as close to real as possible. The subject of the research in the article is an aviation simulator on the Stewart platform. The aim is to create and analyze an flight simulator platform using software. The paper presents the already existing flight simulator and its characteristics. Taking into account its dimensions and weight, the platform is modeled in SolidWorks. The kinematic diagram of the type design (6-6) is selected and presented. The basic equation of dynamics for calculating platform motion law for given values of the control forces is given. Also using this equation it is possible to find the controlling forces knowing the law of motion. The developed 3D model consists of two platforms, a movable and a stationary one. The legs with automatically variable length are attached to the platform using hinges. Selected material aluminum alloy type 2024 from which the platform is created. Selected material aluminum alloy type 2024 from which the platform is created. Static analysis of the loaded platform was performed. By loaded platform is meant that in the places where the simulator and the pi-lot's seat are installed, loads equal in weight to the simulator and the maximum weight of the seat with the pilot are applied. The anal-ysis includes such epurfaces: loads to assess whether the structure can support a given weight, displacement, deformation, safety margins and a Design Insight plot to evaluate design details. Identification of elements that are most likely to start collapsing under the weight of the simulator. The research was performed using SolidWorks Simulation software. Based on the data obtained from the plot, conclusions were made about the performance and safety of the developed platform.

Timber-concrete composite (TCC) connections are crucial elements for transferring loads and dissipating energy for a timber-concrete hybrid system under seismic load. This work investigates the mechanical characteristic of TCC bolted connections and simulates the hysteretic behavior using the simplified models. Specifically, a total of 12 TCC bolted connections were tested subjected to cyclic loading. The variables of bolt diameter, timber thickness and steel pad are investigated. The tested results showed that the connections without steel pads failed with one hinge, whereas those with steel pads failed with two hinges. The steel pad can effectively improve the load-carrying capacity and energy-dissipating capacity. The tested hysteretic curves exhibited strength and stiffness degradation, as well as pinching effect. According to the tested data, the simplified models assigned to two different hysteretic models of Saws and Pinching4 are analyzed and compared. The simulated hysteretic curves from both the Saws and Pinching4 models are consistent with the tested data. The obtained model associated with calibrated parameters is quite useful when such TCC connections are embedded into the analysis of the whole structure.

Prefabricated buildings are green and environment-friendly, with high construction efficiency. Concrete-filled steel pipe structures have high bearing capacity and strong deformation ability. Special-shaped column frame structures of prefabricated concrete-filled circular steel pipe with built-in lattice can give full play to the advantages of prefabricated buildings and concrete-filled steel pipe structures, with the advantage of high space utilization rate of special-shaped column structures. In order to study Seismic performance of frame in special-shaped columns of prefabricated concrete-filled circular steel pipe with built-in lattice, a full-scale middle frame model specimen with two floors and two spans was designed, and the failure mechanism of the specimen was obtained by low-cycle loading test. The hysteretic performance, deformation capacity, energy dissipation capacity and stiffness degradation of the specimen were analyzed. The results showed that the failure mechanism of the prefabricated concrete-filled steel tubular special-shaped column is a typical beam hinge mechanism, which meets the design requirements of “strong column and weak beam”. The special-shaped columns frame of built-in concrete-filled circular steel pipe has full hysteretic curve, good ductility and energy dissipation capacity, and stable stiffness degradation. When the specimen is damaged, the inter-story drift angle reaches 1/23, which is much higher than the limit requirement of elastic–plastic inter-story drift angle of 1/50 under strong earthquake. The existence of built-in concrete-filled steel pipe changes the bearing mechanism of the structure. After the external concrete falls off, the internal force of the structure redistributes, forming a stress system of built-in concrete-filled steel pipe truss. The post-cast joint between overlapping precast column and superposed beam and grouting connection joint between precast column and column sleeve are not damaged, and the fabricated joints are safe and reliable.

Quasi-static testing was conducted on a single-bay two-story cellular steel beam structure with composite concrete slab to evaluate the seismic performance of the frame under cyclic lateral loading. Test measurements of the cellular beams, joints, columns, and slabs were presented and analyzed in detail. The failure modes and damage mechanisms of the specimens were investigated, and the hysteresis behavior, strength and stiffness degradation, ductility, and energy dissipation of the structure were analyzed. The composite effects of the concrete slabs under cyclic loads were also evaluated. The results indicate that the structure exhibited a full hysteresis loop, and the structure had a good capacity for energy absorption. After the peak load of the skeleton curve for the upper frame layer had been reached, the bearing capacity of frame A decreased more rapidly than that of frame B, and the strength attenuation and stiffness degradation were more obvious for frame A. The ductility coefficients of the upper layers of the two frames were both greater than 3.0. Through the analysis of the destruction process, the failure mode of the frame was researched. Plastic hinges were formed around the opening before the joints yielded, and the positions of the plastic hinges were a considerable distance from the beam-to-column joints. Damage to the structure was presented as a typical plastic hinge failure, which protected the beam-to-column nodes and avoided brittle failure.

To understand the origin of curved subduction zones has been one of the major challenges in plate tectonics. The Mongol-Okhotsk Orogen in Central Asia is characterized by the development of a U-shaped oroclinal structure that was accompanied by the continuous subduction of the Mongol-Okhotsk oceanic plate. Therefore, it provides a natural laboratory to understand why and how a subduction system became tightly curved. In this study, we provide the first structural observation around the hinge of the Mongolian Orocline (the Zag zone in Central Mongolia), with an aim to constrain the oroclinal geometry and to link hinge zone structures with the origin of the orocline. Our results show that rocks in the Zag zone are characterized by the occurrence of a penetrative foliation that is commonly subparallel to bedding. Both bedding and dominant fabric in the Zag zone are steeply dipping, and their strike orientations in a map view follow a simple curve around the hinge of the Mongolian Orocline, thus providing the first structural constraint for 3D geometry of the orocline. A secondary penetrative fabric parallel to the axial plane of the orocline was not observed, indicating a low degree of orogen-parallel shortening during oroclinal bending. Combining with available geological and geophysical data, we conclude that the Mongolian Orocline was developed in a period of Permian to Jurassic, and its origin was linked to the subduction of the Mongol-Okhotsk oceanic slab. We consider that the low-strain oroclinal bending likely resulted from the along-strike variation in trench retreat, which was either triggered by the negative buoyancy of the Mongol-Okhotsk oceanic slab, or driven by the relative rotation of the Siberian and North China cratons. Our results shed a light on 3D geometry and geodynamic mechanisms of large-scale oroclinal bending in an accretionary orogen.

Epithelial tissues are sheet-like tissue structures that line the inner and outer surfaces of animal bodies and organs. Their remarkable ability to actively produce, or passively adapt to, complex surface geometries has fascinated physicists and biologists alike for centuries. The most simple and yet versatile process of epithelial deformation is epithelial folding, through which curved shapes, tissue convolutions and internal structures are produced. The advent of quantitative live imaging, combined with experimental manipulation and computational modeling, has rapidly advanced our understanding of epithelial folding. In particular, a set of mechanical principles has emerged to illustrate how forces are generated and dissipated to instigate curvature transitions in a variety of developmental contexts. Folding a tissue requires that mechanical loads or geometric changes be non-uniform. Given that polarity is the most distinct and fundamental feature of epithelia, understanding epithelial folding mechanics hinges crucially on how forces become polarized and how polarized differential deformation arises, for which I coin the term 'mechanical polarity'. In this review, five typical modules of mechanical processes are distilled from a diverse array of epithelial folding events. Their mechanical underpinnings with regard to how forces and polarity intersect are analyzed to accentuate the importance of mechanical polarity in the understanding of epithelial folding.

A Consistent One-Bay Frame (COBF) simplified model for the efficient estimation of Engineering Demand Parameters (EDPs) in Steel Moment Resisting Frames (SMRFs) with equal and unequal bay lengths is proposed. The geometry of the Substitute One-Bay Frame (SOBF) simplified model has been used, and the elastic and inelastic properties of the beams and columns in this model are determined using an energy consistent approach in a way that the energy balance is established between the members of the original SMRF and the SOBF simplified model. This way, the SOBF simplified model, which originally could only be used for MRFs with equal bay lengths, can now be used for MRFs with any geometric arrangement for bay lengths. Two 9- and 20-story SMRFs with equal bay lengths and two others with unequal bay lengths have been employed as structural models. The concentrated plastic hinges with modified Ibarra-Medina-Krawinkler (IMK) deterioration model have been used to apply strength and stiffness deterioration in numerical models. The accuracy of the proposed simplified model in estimating the EDPs along the height of the structure has been evaluated using Nonlinear Time History Analysis (NLTHA) under 22 pairs of FEMA P-695 earthquake records at the three seismic intensity levels of SLE, DBE, and MCE. The proposed simplified model has been compared with the Consistent Generic (CG) simplified model previously developed for SMRFs. This comparison suggests that the proposed simplified model is more efficient and reliable. Evaluating the seismic performance of the proposed simplified model using the conventional Incremental Dynamic Analysis (IDA) method and the Endurance Time Analysis (ETA) method at all of the seismic intensity levels reveals that using the COBF simplified model along with the ETA simplified method not only reduces the Degrees of Freedom (DOFs) of the original SMRF and the number of the NLTHAs but also leads to a proper estimation of the EDPs of the original SMRF from low seismic intensity level to collapse intensity level. Therefore, it is very helpful to use it for reducing the complexities of the new generation of Performance-Based Earthquake Evaluation.

Bolts, nails and screws are the most commonly used connectors in steel-to-timber composite (STC) system. Glued-in rod (GIR) as one kind of connectors for timber structures, is also supposed to be used as the connections in STC system. This paper reports an experimental campaign on steel plate-to-timber connections with single GIR and wood screw fastener aiming to investigate the shear performance of the connections. The experimental results indicated that under lateral load, the fasteners exhibited “one hinge” or “two hinges” deformation modes typically, which are greatly associated with the fastener anchorage length. The load-relative displacement curves were generally characterized by a linearly increasing response followed a yield plateau and a secondary non-linearly increasing response indicating the so-called rope effect of the fasteners. The fastener anchorage length showed significant influence on the load capacity of the screwed steel plate-to-timber connections while did not affect the load capacity of the steel plate-to-timber connections with GIR fasteners. The initial stiffness and ductility of the steel plate-to-timber connections were obviously influenced by the fastener anchorage length. A finite element (FE) model was developed to simulate the joint behaviour and the simulation results are in good agreement with test results. Finally, the load-carrying capacity of the steel plate-to-timber connections with screw and GIR fasteners was predicted by the calculation model reported in Eurocode 5 and a new proposed calculation model, respectively.

This primary aim of this philosopher paper investigates the efficacy of the noise dissolving algorithm hinge on TTSD (Triple Threshold Statistical Detection) filter that has been originated since 2018 is one of the highest efficacy for dissolving RIIN (Random-Intensity Impulse Noise), exclusively at dense distribution. As a results, there are three essential contributions: the exhaustive explanation of the TTSD filter algorithm and its computation examples, the calculation simulation of noise apprehension correctness and overall comparative simulation of noise dissolving effectiveness. For TTSD filter, three malleable offsets that are the complementary requirement are employed in the TTSD filter that can adequately resolve the limitation of the antecedent noise dissolving algorithms. The first malleable offset is calculated for determining the noise characteristic of all elements by using the mathematical verification. Next, the second malleable offset is calculated for determining the another noise characteristic by using the normal distribution mathematical verification (the average value and standard deviation value). Later, the third malleable offset is calculated for determining the another noise characteristic by using the quartile mathematical verification (median value). In the simulation inquisition, the bountiful standard portraits that are desecrated by RIIN (Random Intensity Impulse Noise) with many dense distributions are experimented by noise dissolving algorithm hinge on TTSD in both noise segregation and noise dissolving perspective.

Background Open-wedge high tibial osteotomy (OWHTO) has extensively been used for the correction of medial knee osteoarthritis. The proximal tibia is osteotomized and distracted to enable the rotation of tibial fragments around the lateral hinge. Both, wedge inclination on the medial side and saw progression near the lateral cortex determine the hinge orientation. This study focused on the interaction between hinge orientation and distraction sites on the coronal, sagittal, and horizontal planes of the distracted plateau. Methods Three parameters of wedge inclination, saw progression, and distraction site (i.e., posterior, middle, and anterior) were systematically varied. Using a three-dimensional (3D)-printing technique, the osteotomized tibiae were manufactured as the specimens for the in vitro experiments. In total, 27 variations (3 × 3 × 3) were tested. After distraction, the specimens were scanned by computed tomography and spatially registered with the original tibia to compare the 3D angles of the distracted plateaus. Results Coronal rotation is the main purpose of OWHTO; therefore, all the values of the coronal angles were positive and significantly higher than the other two. The sagittal and horizontal angles had relatively similar values. Distraction in the middle site seems to have the least impact on sagittal rotation. Large angles of hinge orientation show the superior ability in adjusting the sagittal rotation than small angles. However, the larger the horizontal angles the greater the wedge inclination. Conclusions The wedge inclination, saw progression, and distraction site constitute a complex mechanism that affects 3D rotations of the distracted plateau. The coronal angles are sensitive to hinge orientation and distraction site. The intraoperative planning of manipulating hinge orientation is an effective method to adjust sagittal rotation. A large angle of wedge inclination is an indicator of horizontal rotation, and it should be carefully mitigated to reduce the risk of cracking in the lateral hinge.

The present work concerns the numerical investigation of reinforced concrete frame buildings containing masonry infill panel under seismic loading that are widely used even in high seismicity areas. In seismic zones, these frames with masonry infill panels are generally considered as higher earthquake risk buildings. As a result there is a growing need to evaluate their level of seismic performance. The numerical modelling of infilled frames structures is a complex task, as they exhibit highly nonlinear inelastic behaviour, due to the interaction of the masonry infill panel and the surrounding frame. The available modelling approaches for masonry infill can be grouped into two principal types; Micro models and Macro models. A two dimensional model of the structure is used to carry out non-linear static analysis. Beams and columns are modelled as non-linear with lumped plasticity where the hinges are concentrated at both ends of the beams and the columns. This study is based on structures with design and detailing characteristics typical of Algerian construction model. In this regard, a non-linear pushover analysis has been conducted on three considered structures, of two, four and eight stories. Each structure is analysed as a bare frame and with two different infill configurations (totally infilled, and partially infilled). The main results that can be obtained from a pushover analysis are the capacity curves and the distribution of plastic hinges in structures. The addition of infill walls results in an increase in both the rigidity and strength of the structures. The results indicate that the presence of non-structural masonry infills can significantly modify the seismic response of reinforced concrete "frames". The initial rigidity and strength of the fully filled frame are considerably improved and the patterns of the hinges are influenced by structural elements type depending on the dynamic characteristics of the structures. Doi: 10.28991/cej-2021-03091764 Full Text: PDF

Improving the productivity of machinery and auxiliary equipment has long been one of the main directions for the world industry development. Efforts to gain fractions of a percent of the indicator require both the improvement of existing mechanisms and the introduction of faster manipulators, such as a delta robot. One of the key design tasks for such mechanisms is determining the required drive characteristics. The article presents a solution of the inverse kinematics problem for a delta robot. An algorithm for planning the movement of the working body for performing a typical operation of object permutations is described. The issues of modeling the movement of a robot in the computer-aided design system Autodesk Inventor are considered. The dynamic characteristics of the manipulator have been obtained, on the basis of which it is possible to select drives, bearings and kinematic pairs.

Purpose To verify whether lateral hinge fracture (LHF) affects correction accuracy in open-wedge high tibial osteotomy (OWHTO) and to identify the fracture characteristics responsible for inaccurate correction, including LHF type and hinge location. Methods Patients undergoing OWHTO with locking plate fixation between 2010 and 2016 were retrospectively reviewed. Patients who did not have a minimum 2-year of follow-up or postoperative long-standing hip-to-ankle radiographs were excluded. Correction accuracy was assessed using the weight-bearing line ratio: 57% to 67%, planned correction; 50% to 70%, acceptable correction; otherwise, inappropriate correction. The association between LHF and correction accuracy was assessed using the χ2 test. To identify the fracture characteristics responsible for inaccurate correction, LHF type (stable type 1 and unstable types 2 and 3) and hinge location (shallow osteotomy, deep osteotomy, and occult complete osteotomy) were analyzed using ordinal logistic regression analysis, taking other related demographic and radiologic factors into account. Clinical outcomes according to LHF type were evaluated using the Hospital for Special Surgery scores. Results A total of 148 cases were included; 41 (27.7%) showed LHF: type 1, 32 cases; type 2, 7 cases; and type 3, 2 cases. Planned, acceptable, and inappropriate corrections were noted in 63 (42.6%), 36 (24.3%), and 48 (32.4%) cases, respectively. LHF had a significant association with correction accuracy (P = .010). Regarding fracture characteristics, unstable LHF and occult complete osteotomy were significant risk factors (P = .016 and P = .004, respectively). Specifically in cases of stable LHF, occult complete osteotomy adversely affected correction accuracy (P = .025). No difference was found in the final Hospital for Special Surgery scores according to LHF type (P = .816). Conclusions LHF affected the accuracy of coronal alignment correction in OWHTO. Unstable LHF or occult complete osteotomy were risk factors for inaccurate correction. Even among stable LHFs, those with occult complete osteotomy could lead to inaccurate correction. Level of Evidence Level III, retrospective cohort study.

Compliant mechanisms are state of the art in micropositioning stages due to their many beneficial features. However, their design usually compromises between motion range, motion accuracy and design space, while mechanisms with distributed compliance are mostly applied. The further use of flexure hinges with common notch shapes strongly limits the stroke in existing high-precision motion systems. Therefore, this paper presents a high-precision compliant XY micropositioning stage with flexure hinges capable of realizing a motion range of ± 10 mm along both axes. The stage is based on a novel plane-guidance mechanism, which is optimized to realize a precise rectilinear motion of the coupler link while keeping the rotation angles of all hinges below 5 ° . The XY motion is then achieved by coupling two of these mechanisms in a serial arrangement. Next, the synthesis of the monolithic XY stage is realized by replacing all revolute joints of the rigid-body model with flexure hinges using optimized power function notch shapes. Emphasis is also placed on the embodiment design of the stage and the actuator integration to minimize possible error sources. Finally, the quasi-static behavior of the compliant stage is characterized by a simulation with a 3D FEM model and by an experimental investigation of a prototype. According to the results, the developed compliant XY micropositioning stage achieves a maximum positioning deviation of less than 10 μm in both axes and a yaw error of less than 100 μrad over a working range of 20 mm × 20 mm with a comparably compact design of the compliant mechanism of 224 mm × 254 mm.

This work introduces a three-dimensional (3D) right circularly corner-filleted flexible hinge composed of four planar segments that are serially connected and located in two planes of the global Cartesian frame. The 3D hinge configuration realizes full load-displacement coupling in terms of the six degrees of freedom (DOF) at its free end, enhancing thus the motion capability, range and versatility. A linear analytical compliance model is developed to describe the load-deformation behavior of this hinge using matrix formulation. Thorough finite element simulation confirms the analytical model results. A comprehensive study is performed based on the analytical model to identify the influence of the hinge geometric parameters on its deformation response. A parallel-connection hinge is also introduced, which consists of three identical 3D Cartesian hinges joined to a rigid link and resulting in a tripod stage. A prototype stage is manufactured and experimentally tested whose results validate the analytical model predictions. Further analysis studies the static regular and parasitic behavior of the stage in terms of its defining geometry.

This paper focuses on the configuration design of flexure hinges with a prescribed compliance matrix and preset rotational center position. A new method for the topology optimization of flexure hinges is proposed based on the adaptive spring model and stress constraint. The hinge optimization model is formulated by maximizing the bending displacement with a spring while optimizing the compliance matrix to a prescribed value. To avoid numerical instability, an artificial spring is used as an auxiliary calculation, and a new strategy is developed for adaptively adjusting the spring stiffness according to the prescribed compliance matrix. The maximum stress of flexure hinge is limited by using a normalized P-norm of the effective von Mises stress, and a position constraint of rotational center is proposed to predetermine the position of the rotational center. In addition, to reduce the error of the stress measurement, a simple but effective filtering method is presented to obtain a complete black-and-white design. Numerical examples are used to verify the proposed method. Topology results show that the obtained flexure hinges have the prescribed compliance matrix and preset rotational center position while also meeting the stress requirements.

Hinge motions are essential for many protein functions, and their dynamics are important to understand underlying biological mechanisms. The ways that these motions are represented by various computational methods differ significantly. By focusing on a specific class of motion, we have developed a new hinge-domain anisotropic network model (hdANM) that is based on the prior identification of flexible hinges and rigid domains in the protein structure and the subsequent generation of global hinge motions. This yields a set of motions in which the relative translations and rotations of the rigid domains are modulated and controlled by the deformation of the flexible hinges, leading to a more restricted, specific view of these motions. hdANM is the first model, to our knowledge, that combines information about protein hinges and domains to model the characteristic hinge motions of a protein. The motions predicted with this new elastic network model provide important conceptual advantages for understanding the underlying biological mechanisms. As a matter of fact, the generated hinge movements are found to resemble the expected mechanisms required for the biological functions of diverse proteins. Another advantage of this model is that the domain-level coarse graining makes it significantly more computationally efficient, enabling the generation of hinge motions within even the largest molecular assemblies, such as those from cryo-electron microscopy. hdANM is also comprehensive as it can perform in the same way as the well-known protein dynamics models (anisotropic network model, rotations-translations of blocks, and nonlinear rigid block normal mode analysis), depending on the definition of flexible and rigid parts in the protein structure and on whether the motions are extrapolated in a linear or nonlinear fashion. Furthermore, our results indicate that hdANM produces more realistic motions as compared to the anisotropic network model. hdANM is an open-source software, freely available, and hosted on a user-friendly website.

This paper content is structure subjected sudden story drift as a result from earthquakes, forming hinges and eventually collapsing. The aim of this paper is to develop building thirty story building for seismic in Khartoum using finite element method (FEM) and the equivalent lateral force (ELF) procedure of American code ASCE 7-16. In current work the thirty-story reinforced concrete building was considered is to analyze the seismic behavior of the reinforced concrete structure to find the drift between the story by finding the maximum displacement from the program that causes the building to collapse, by choosing the shear wall as the support system to resist the lateral load and by looking to model the building inclined to the horizontal plane. Calculations were also made on the drift between the story to compare with the allowable drift. It is implemented in the Robot structural program - an ingenious program for designing and analyzing lateral (seismic) loads.

This paper presents a topology optimization method to design the piezoelectric stick–slip actuator. In particular, the vertical input displacement can be converted to the oblique displacement by the flexure hinge driving mechanism, and the large-stroke motion is realized. Based on the solid isotropic material with penalization (SIMP) model and combined with the motion characteristics of the stick–slip actuator, in order to obtain a larger output displacement and limit the parasitic displacement, the ratio of output displacement to input displacement is maximized as the objective function, and the relationship between parasitic displacement and output displacement is considered as a constraint condition. The method of moving asymptotes (MMA) is used to solve the optimization problem, and the driving mechanism structure is designed by the topology optimization result. The feasibility and reliability of the driving mechanism are verified by finite element analysis (FEA), then the prototype is fabricated. Experimental test results indicate that the velocity of the actuator reaches 15.25 mm/s under the locking force of 1 N and frequency of 650 Hz, and the resolution of 96 nm is achieved. This work shows that the topology optimization method can be used to improve the performance of the actuator.

Made available in DSpace on 2022-05-01T09:31:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 Machining of advanced ceramics in the green state aims to achieve complex geometry with near-net-shape dimensions minimizing machining steps after sintering, good surface finish, economic efficiency and flexibility, and reduced process costs, in addition to the removal of the outer layer with potential defects and prior correction of distortions expected during sintering. However, the pressure exerted by the cutting edge plus the removal of lumps can introduce damage such as chipping to the green part due to its low mechanical strength, especially with inappropriate cutting parameters. Ultrasonic-assisted machining on the cutting tool has been applied to improve machining performance by improving surface finish, reducing machining forces, and reducing tool wear. This paper proposes a study on ultrasonic-assisted turning (UAT) of ceramic materials in a green state where a flexure hinge was developed for allowing tool vibration only toward the depth of cut direction. A central composite design of experiments (DOE) with a full factorial design was performed to determine the proper condition of the cutting parameters. The results showed that the UAT on ceramic materials in a green state compared to conventional turning (CT) provided process benefits through improved surface finish due to reduced lump pull-outs, decreased tool flank wear by 34%, and reduced machining forces (10%). Finally, ultrasonic vibration promoted intermittent part-tool contact releasing the removed debris, which increases material removal at the chip-tool interface and consequently diminishes material adhesion on the tool. Department of Mechanical Engineering São Paulo State University (Unesp) Department of Mechanical Engineering University of São Paulo (USP) Department of Mechanical Engineering Federal Technological University of Paraná Department of Mechanical Engineering São Paulo State University (Unesp)

Multiframe PC box-girder bridge with intermediate hinges is a kind of bridge having complex structural characters, which is very quintessential in California. In this study, a typical bridge was adopted to establish a nonlinear dynamic model through OpenSees platform. Intermediate hinge and inhibiting devices in it were elaborately simulated. Meanwhile, pushover analysis was used to reinstate a specimen of column test, which has the similar ratio of reinforcement to the typical bridge, and the hysteretic model parameters of the longitudinal steels inside columns were obtained. The damage indexes of column and hinge, which are primary components, under different limit states were acquired by moment-curvature analysis. Taking into account the uncertainty, nonlinear time-history analysis of the bridge was carried out through a suite of synthetic ground motions. Subsequently, a probabilistic seismic demand model was developed, and fragility curves were further focused on. According to fragility assessment, the conclusion shows that columns and hinge restrainers exhibit high fragility, and bridge system fragility is gradually determined by column fragility along with aggravating of the damage state. Unseating of girder can hardly occur at abutments and intermediate hinges. Moderate limit state could be exceeded in the positions of plug-type concrete structures in intermediate hinges, which tends to create transverse and vertical cracks, furthermore causing reinforcements yield. It indicates that it would severely underestimate the seismic fragility of intermediate hinges without considering the elaborate simulation of hinges.

Rolling bearings are widely used in the products of aviation and space technology. To ensure their long-term trouble-free operation, it is necessary to have accurate and reliable information about the forces acting on the bearings. The required values of forces and, accordingly, the required durability of bearings are usually determined on the basis of the traditional design scheme of a double-support beam (smooth beam mounted on two hinged supports). The paper presents a new interpretation of the features of the operation of bearing units on ball radial single-row bearings installed according to the cross located arrangement. It is shown that under conditions of combined loading, including radial and axial forces, the generally accepted theoretical model of a doublesupport beam is not implemented. There is no single calculation model that adequately reflects the nature of the interaction of bearing parts over the entire range of external loads. In the most general case, this model can be represented by a sequence of five statically indeterminate calculation schemes, which are modified and transformed into one another. So, with an increase in the external radial force, the cantilevered beam with additional hinge support scheme is first implemented, which, then, is transformed into the double-sided jamming scheme, and that, later, is transformed into the two double hinge supports scheme. It is also possible to implement two intermediate transition schemes. A specific example shows that in the products of aviation and space technology, determining the durability of bearings based on the traditional model is not advisable, since it can give an overestimated value with an error of 28,37 to 26663,9 times.

Vertical mass isolation approach is a new technique in which an individual structure is divided into two distinct subsystems and each possesses different characteristics. Such two subsystems–mass and stiff subsystems– are interconnected with passive dampers in vertical layers at the height of the frame. The primary task of such passive devices is to reduce the structure's seismic reactions by dissipating more of the seismic forces, as well as regulating the amount of structure displacement. In this paper, two models of stiff subsystem placement are introduced, the inner stiff subsystem(ISS) and the outer stiff subsystem(OSS). Structural models are introduced in two types of five and ten-story for both ISS and OSS systems. Metallic dampers were used as fuses to reconnect the isolated structures. For all models under seven distinct earthquake ground motions, nonlinear time history analyses were executed. The findings related to base shear forces, the shape of plastic hinges in structural components, the responses of roof acceleration, and the dampers’ hysteresis behavior are studied. Based on the numerical data, the ISS system has a minor advantage over the OSS system in improving the structure's seismic efficiency and reducing seismic reactions.

In the extension project of the China National Academy of Painting, the radial spherical plain bearing (RSPB) is used in a structural joint with an inserted plate. This new structural RSPB joint has complicated mechanical behaviors and universal rotational performance. In this work, the simulation and experiment methods were used to investigate the RSPB joint mechanical properties (uniaxial ultimate bearing capacity, failure mode) and reliability. Furthermore, the out-of-plane rotational performance was studied with eight finite models for the application. According to FEA and test results, this new RSPB joint has functional mechanical properties. It is useful in steel truss structures and provides a possibility for engineers to design hinge joints in building structures.

A three-dimensional (3D) FBG accelerometer was proposed by installing three FBGs in an integrated oscillator structure which consists of two pairs of flexible hinges, a thin cylinder mass block and a base. The theoretical model of the proposed 3D accelerometer was established, and the dynamic response characteristics of the 3D accelerometer with optimal structural parameters were simulated using finite element software. Lots of sensing tests were finished and the sensing data showed that the sensitivities of the proposed 3D accelerometer in X-, Y-, and Z-directions are 108.7 pm/g, 144.2 pm/g, and 27.9 pm/g respectively, the working frequency range in X- and Y- directions are 40 – 300 Hz, and the acceleration amplitude range is 1 – 10 g. The proposed 3D accelerometer has the advantages of small size (28 mm $\times38$ mm $\times38$ mm), light weight (42 g), and simultaneous measurement of multi-dimensional acceleration.

To mitigate the deficiency of the conventional steel frames, a novel steel frame system using rocking truss (SFWRT) and self-centering energy dissipative devices (SCED) was developed. The SCED consists of structural members, pre-tension tendons, abutting element and friction dissipation devices, which exhibits excellent self-centering and energy dissipation capacity. This new structural system is analyzed using Incremental Dynamic Analysis method (IDA). A scaled earthquake acceleration response spectrum from a specified ground motion was used in this analysis. It is found that the formation of the plastic hinges of the structural components includes four stages: emergence, developing, degradation and completely bearing capacity loss. A comparative study is also made to investigate the development of these plastic hinges under different ground motions in both traditional steel frame and SFWRT. The results for evaluating the lateral collapse resistance capacity indicate that the rocking truss can significantly decrease the structural dynamic response and improve the seismic performance of buildings. The collapse probability curves of the steel frame and SFWRT based on three limit states are compared. It is found that the rocking truss is helpful to reduce the collapse probability under earthquakes. The damage of the steel frame as well as the expected loss of the main structure after an earthquake can be significantly reduced with the help of rocking truss, which would also reduce the repair cost and improve the structural resilience under earthquakes significantly.

The present work deals with the improvement of the seismic performance of a Single Story-Single Bay Special Truss Moment Frame (STMF) by incorporating Shape Memory Alloys (SMAs) as dissipation devices in the special segment, which can recover their initial geometry after mechanical distortion by unloading through the phase transformation (martensitic-austenitic phase). STMFs were initially designed with a special segment located in the middle of the truss to dissipate the input energy through the formation of plastic hinges at the four corners of the chord members. This mechanism is replaced with the input energy dissipation through the SMA deformation in a pin-ended special segment. In what follows, the frame at hand is examined incorporating SMA bars per diagonal of either 0.025 m or 0.035 m in diameter, restrained against buckling, simulated via a 4-DOF mechanical model consisting of two lumped masses, under selected ground motions. To further evaluate the performance of the frame with SMAs incorporated and at the same time verify the model, a non-linear dynamic time-history analysis is conducted using SeismoStruct Finite Element software. The response of the proposed system is compared with the one of the conventional one. Results show that the proposed system leads to a decrease of the maximum displacement and potentially allows a much lighter construction.

The stiffness of the stiffener plate of a tube-gusset plate joint (TGPJ) with a multi-ring stiffener plate is much larger than that in the chord wall. The load on the gusset plate will be concentrated in the area where the stiffener plate is located, and the joint will eventually fail in this area as a result of the ultimate state of the ring stiffener plate. This study investigated the stiffness and ultimate strength of a ring stiffener plate under an axial load. First, an experimental study was carried out on X-shaped TGPJs with double-ring stiffener plates. The failure mode of the joints was clarified, the variation law of the joint stiffness was revealed, and the rationality of using a 3% chord wall deformation as the criterion for determining the ultimate state of joints was verified. Then, based on the test results, finite element models (FEMs) of the X-type joint and ring stiffener plate were established, and their accuracy was verified. Numerical analysis results clarified the synergistic mechanism of the double-ring stiffener plate of an X-type joint, and the equivalence between the joint failure and the single-ring stiffener plate failure was revealed. Different nominal yield strength parameters (345 and 420 MPa), different dimensions (D/t = 32.3–55.9 and R/tr = 6–33.3), and different load conditions (tension and compression) for ring stiffener plates were analysed, and the accuracy of the calculation methods for the limit state of the ring stiffener plates proposed in this paper was verified. A comparison showed that the ‘four-hinged ring beam model’ proposed in this paper did not consider the changes in the curvature of the ring beam between plastic hinges. Thus, the calculation results of the model were obviously conservative, and the ‘deformation stiffness model’ was more accurate than the calculation results of other methods mentioned in this paper.

Although research on epistemic injustice has focused on the effects of prejudice in epistemic exchanges, the account of prejudice that emerges in Fricker's (2007) view is not completely clear. In particular, I claim that the epistemic role of prejudice in the structure of testimonial justification is still in need of a satisfactory explanation. What special epistemic power does prejudice exercise that prevents the speaker's words from constituting evidence for the hearer's belief? By clarifying this point, it will be possible to address two more general issues concerning the nature of prejudice: its resistance to counterevidence and the steps involved in overcoming prejudice. I propose a hinge account of prejudice, based on the recent perspective of hinge epistemology, to help clarify these aspects. According to the hinge account, prejudices share a fundamental feature with hinges: they work as norms of evidential significance, and as such, they determine what can and cannot count as evidence for belief.

In order to obtain a new structure of beam flexure hinge with good performance, the flexure hinge based on the X-lattice structure is researched in this paper. The truss model in the finite element method is used to model the 6-DOF compliance of the flexure hinge based on the X-lattice structure. The influence of structural parameters on the compliance and compliance ratio of flexure hinges is analyzed based on this model, and the performance is compared with the traditional beam flexure hinge of the same size. In order to design a flexure hinge based on the X-lattice structure with good comprehensive performance, this paper proposes an intelligent structure optimization method based on a genetic algorithm. The feasibility of the optimization algorithm is verified by an example.

The experience of running drives of most of heavy-duty rolling mills shows that the designs of universal spindles with blade hinges under conditions of increased alternating loads are most acceptable comparing with other spindles types. Open friction surfaces are the drawbacks of these types of spindles, which complicate the matter of continuous supply of lubrication. Perfected effective system of forced lubrication of rolling mill spindles hinges proposed. The facility for their lubrication has a bearing support of balancing design, spindle, in radial holes of which spring-loaded plungers are installed in a diametrically opposite order. Besides, the facility has suction valves and force valves installed in the spindle axial holes, connecting with the radial ones. A methodology proposed to select the eccentricity of the internal cylindrical surface of the bearing support of the spindle hinge, the axis of which is located eccentrically relative the spindle rotation axis. A calculating scheme and a mathematical model of the process of lubrication supply into joints of rolling mill spindle hinge elaborated. A differential equation of lubrication motion in the conical slot of the hinge between a blade and insertions drawn up. Parameters of hydrodynamic motion of lubrication in the conical slot established. Modes of the lubrication motion in the conical slot between roller blade and hinge insertion determined. Based on experience of operation of friction couple bronze-steel, a lubrication for rolling mills universal spindles proposed. To improve the operation characteristics of hinges based on the friction couple bronze-steel, a thick lubrication having antifriction properties namely based on oils with additives ИП-10, КП-10 and ДФ-11 proposed. Dependence of pressure distribution along the length of the hinge conical slot presented for various lubrications of low viscosity (ИП-10 + ДФ-11) and high viscosity (КП-10 + ДФ-11). The quality effect of the speed of roller blade movable wall on distribution of speeds of lubrication layer motion over the height of the hinge conical slot for comparatively low and comparatively high boundary speeds demonstrated.

Within the framework of traditional approaches to checking for resistance of reinforced concrete buildings and structures to the progressive collapse development, membrane (chain) forces in a damaged structural system are calculated separately, without considering its non-linear bending behavior during the formation of the plastic hinges and without checking the possibility of achieving large deflections.The authors propose an approach to modelling a nonlinear quasi-static reaction of a damaged structural system in an accidental design situation. This approach considers non-linear bending and the resistance of reserved horizontal ties, considering their ultimate ductility. The authors verified the proposed approach based on the results of experimental studies by others researchers.An example of the application of the proposed approach in assessing the robustness of a structural system made of precast concrete with a sudden removal of the central column is considered. In accordance with the provisions of the energy approach, an analysis is made of the contribution of individual resistance mechanisms to the total quasi-static and dynamic resistance of the damaged structural system.We show that the proposed calculation model adequately describes the behavior of a damaged structural system in an accidental design situation, and therefore to carry out parametric studies and check the robustness of building structures.

Este estudo é a avaliação do método arbitrário de determinação do eixo intercondilar da mandíbula em confronto com a determinação do mesmo por meio de um arco facial cinemático., This study is for the arbitrary intercondilar to the real intercondilar hinge axis, with the help of a kinematic face bow. In the 21 patients we determined the real and the arbitrary hinge axis, registering the results in a melimetred paper. The results obtained were compared confirming that 58% the real intercondilar hinge axis was localized into a radius of 4 mm from the arbitrary intercondilar hinge axis.

The continuing efforts of automotive technology aim to deliver even greater safety benefits and reduce the weight of a vehicle. Thin-walled beams (TWB) are widely used as strengtheners or energy absorbers in vehicle bodies due to their lightweight and excellent energy absorption capacity. Thus, researchers are interested in the collapse behaviour and mechanical properties of thin-walled beams under static and dynamic loadings. Circular TWB is commonly used in vehicle side doors. In the event of a side collision, this beam deforms and absorbs the greatest amount of impact energy. In this study, the energy absorption capability and crashworthiness of polygonal cross-section TWBs subjected to lateral impact was investigated using numerical simulations. Polygonal TWB ranging from square to dodecagon, as well as circular cross section, were selected for this study. Energy absorption (EA), specific energy absorption (SEA) and crash force efficiency (CFE) crashworthiness indicators are employed to evaluate the bending collapse performance. Because TWB thickness and weight have a greater impact on bending performance, they were kept constant across all polygons. In ABAQUS explicit dynamic software, finite element simulations are performed, and plastic hinges and flattening patterns of all polygons are examined. The results show that heptagon, octagon, and nonagon cross-section TWB perform better in crashworthiness than square and circular TWB.

In order to improve the key performance of the compliant actuators, it is necessary to parametrically optimize the compliant actuators based on the compliance features of flexible hinges. A new structural parameter λ, the compliance ratio, which could reflect the sensitivity of the main form of the output displacement, was proposed and analyzed in detail. A compliant lever actuator was developed, and it was optimized by making use of the parameter λ. The optimization was also validated by finite element method (FEM) simulation and experiment. The simulation and experiment results both show that the magnification ratio of the compliant actuator could be enlarged effectively based on the compliance features of flexible hinges. Finally, an actual application of the linear positioning platform that was driven by the compliant lever actuator directly was carried out, and the experiment data also show that the platform with the optimized actuator has different degrees of optimization in terms of the key performance, including the resolution, the motion speed, and the working stroke. It is helpful to develop the compliant actuators and apply it into the precision engineering.

The documents for risk management and assessment of concrete bridges with half-joints, concrete bridges with deck hinges and post-tensioned concrete bridges in the Design Manual for Roads and Bridges (DMRB) have been rewritten and updated as part of a project to update the entire DMRB suite of documents; they have also been given the new document codes CS 465, CS 466 and CS 467. In bringing these documents up to date there have been significant technical changes introduced, including: a change to the risk management process for half-joints and deck hinges; an update of assessment methods for evaluating half-joints and deck hinges; and improvements to the risk management of post-tensioned bridges. This technical paper outlines the technical background to the key changes and highlights some of the improvements and efficiencies that can be delivered using the new documents.