Hinge Mechanism Research Articles

An Experimental Study of Auxetic Tubular Structures

Auxetic tubular structures are widely known structures, characterized by a negative Poisson’s ratio upon stretching and deformation in the axial and transverse directions, which have numerous application possibilities. In this paper, tubular structures were realized by rolling up planar auxetic structures and using rigid square frames as unit cells. Planar and tubular structures were built from square frames that were 3D printed with plastic or laser-cut from metal. The changes in linear dimensions of the studied structures were based on a hinge mechanism, the functioning of which was experimentally verified on different solutions leading to square unit cells. To connect the square frames of the structure, an innovative solution was used in the form of rotation axes on their surface at a preset distance from the edge of the square frame. The geometric parameter thus introduced was used to determine the relative change in the size of the structure when stretched (i.e., when moving from the closed to the open position).

Achieving smooth motion of stick–slip piezoelectric actuator by means of alternate stepping

Piezoelectric actuators are widely used in various precision instruments owing to their rapid response, high motion accuracy, and immunity to electromagnetic interference. However, achieving smooth motion with a load is difficult when using existing piezoelectric actuators because of their unique driving principle, which limits their application. To achieve smooth motion with a load, a stick–slip piezoelectric actuator using the alternating stepping method was proposed in this study. The two driving feet collaborate to push the slider through a single piezoelectric stack. After considering the structure and working principle of the actuator, a feasibility analysis was performed. Subsequently, the pseudo-rigid-body method, elastic beam method, and finite element method were applied to calculate the displacement relationship of the flexure hinge mechanism. Finally, the prototypes were processed to evaluate their output performance. The comparative experiments explain the role of driving feet-A and B and demonstrate that biped synergy can achieve smooth motion. The subsequent test results show that the designed actuator has exceptionally high adaptability, and the output performance is relatively stable when the pre-tightening deformation is between 50 µm and 200 µm. Most importantly, the designed actuator has good smoothness under no-load and horizontal load conditions, and the maximum speed and resolution are 24.42 mm/s and 0.80 µm, respectively. This is conducive to broadening the application range of piezoelectric actuators.

Postural analysis of side impact WorldSID 50th ATD in highly reclined seats

Objective The anthropomorphic test device (ATD) used in NCAP frontal impact, the Thor 50th, has undergone substantial changes for safety restraint systems testing of upcoming autonomous vehicles (AVs), resulting in the Thor-AV 50 M. Likewise, a deep analysis of the ATD for lateral impacts, the WorldSID 50th, is needed to determine the requirements it has to fulfill to accurately replicate the human body response under lateral impact. This study sets out general considerations regarding the WorldSID 50th ATD design in order to assess its suitability for AV testing scenarios. Methods The WorldSID 50th ATD was placed in a driver seat at a conventional upright driving posture. Relevant body landmarks and angles as well as profile streams of the mockup and the ATD were recorded. The seatback was then reclined stepwise. The ATD was repositioned and the recording procedure repeated at every posture until the seatback was fully reclined. Examination of the ATD assemblies and hinge mechanisms was performed, searching for limitations that could result on inadequate positioning or performance under impact. An eventual SAEJ3016 Level 3 cross-legged posture (SAE J3016, 2021) was considered for examination as well. Results Most relevant anthropometric constraints were noticed at the abdomen and the shoulder and neck assemblies: At the abdomen, a gap between the pelvis and the lower torso appeared at seatback recline angles larger than 30°, likely promoting belt intrusion in case of a test event, and the lumbar spine rubber deformed progressively in a manner that might cause tearing damage. The number and arrangement of the shoulder clevis detents, on the other hand, did not allow the arm to be placed at intermediate positions. Finally, the current neck bracket design allowed head orientation only along the sagittal plane. The head could neither be level at seatback angles larger than 43° nor be placed resting on the head restraint for seatback angle values larger than 59°. Conclusions The WorldSID ATD stands as an accurate 50th percentile human being surrogate in upright and low/mid reclined postures. Some limitations that might constrain its use in AV scenarios, though, appeared at mid/high reclined positions. Hence, design updating of the lumbar, neck and shoulder clevis assemblies, and the implementation of instrumented lower abdomen and lower arms assemblies should be taken into consideration.

Mechanical Design of Self-Reconfiguring 4D-Printed OrigamiSats: A New Concept for Solar Sailing

In this article, a self-reconfiguring OrigamiSat concept is presented. The reconfiguration of the proposed OrigamiSat is triggered by combining the effect of 4D material (i.e. origami’s edges) and changes in the local surface optical properties (i.e., origami’s facets) to harness the solar radiation pressure acceleration. The proposed OrigamiSat uses the principle of solar sailing to enhance the effect of the Sun radiation to generate momentum on the Aluminised Kapton (Al-Kapton) origami surface by transitioning from mirror-like to diffusely reflecting optical properties of each individual facet. Numerical simulations have demonstrated that local changes in the optical properties can trigger reconfiguration. A minimum of 1-m edge size facet is required for a thick-origami to generate enough forces from the Sun radiation. The thick-origami pattern is 3D-printed directly on a thin Al-Kapton film (the solar sail substrate which is highly reflective). An elastic filament (thermoplastic polyurethane TPU) showed best performance when printing directly on the Al-Kapton and the Acrylonitrile Butadiene Styrene with carbon fiber reinforcement (ABS/cc) is added to augment the origami mechanical properties. The 4D material (shape memory polymer) is integrated only at specific edges to achieve self-deployment by applying heat. Two different folding mechanisms were studied: 1) the cartilage-like, where the hinge is made combining the TPU and the 4D material which make the mounts or valleys fully stretchable, and 2) the mechanical hinge, where simple hinges are made solely of ABS/cc. Numerical simulations have demonstrated that the cartilage-like hinge is the most suitable design for light-weight reconfigurable OrigamiSat when using the solar radiation pressure acceleration. We have used build-in electric board to heat up the 4D material and trigger the folding. We envisage embedding the heat wire within the 4D hinge in the future.

Hinged Adaptive Fiber-Rubber Composites Driven by Shape Memory Alloys-Development and Simulation.

Adaptive structures based on fiber-rubber composites with integrated Shape Memory Alloys are promising candidates for active deformation tasks in the fields of soft robotics and human-machine interactions. Solid-body hinges improve the deformation behavior of such composite structures. Textile technology enables the user to develop reinforcement fabrics with tailored properties suited for hinged actuation mechanisms. In this work, flat knitting technology is used to create biaxially reinforced, multilayer knitted fabrics with hinge areas and integrated Shape Memory Alloy wires. The hinge areas are achieved by dividing the structures into sections and varying the configuration and number of reinforcement fibers from section to section. The fabrics are then infused with silicone, producing a fiber-rubber composite specimen. An existing simulation model is enhanced to account for the hinges present within the specimen. The active deformation behavior of the resulting structures is then tested experimentally, showing large deformations of the hinged specimens. Finally, the simulation results are compared to the experimental results, showing deformations deviating from the experiments due to the developmental stage of the specimens. Future work will benefit from the findings by improving the deformation behavior of the specimens and enabling further development for first applications.

Design and Structural Analysis of Trailer Sliding Underrun Protection Device Complied with ECE R58.03 Regulation

In this study, a new, innovative design and structural analysis of trailer sliding rear underrun protection device (RUPD) that complied with UN ECE R58.03 regulation has been made. The technical design norms that determined by United Nations (UN) were considered the key factor for the design parameters. Finite Element Analyses (FEA) were carried out considering the strength test standards specified in the UN ECE R58.03 regulation. Stress distribution was evaluated in the analyzes applied to RUPD. According to stress result of the P1 test condition analysis, the highest stress value was obtained as 839 MPa on hinge mechanism’s pins and also during the P2 condition the stress level on same pins were above 1100 MPa. Considering the stress datas from FEA, it was concluded that the design had to be revised. After revision the stress levels decreased, but levels were close to the yield strength of materials that used. Based on all data obtained, authors decided that design is trustworthy enough to be produced and physical tested, but after the physical testing additional minor revisions may be needed.

On the Geometric Definition of a Hinged Mechanism, Kempe’s Theorem, and Overripe Mathematics

On the Geometric Definition of a Hinged Mechanism, Kempe’s Theorem, and Overripe Mathematics

Plastic behavior and fracture cross section of coiled tubing in the ram shearing process of subsea blowout preventer

For studying the plastic behavior and fracture cross section of sheared drill pipe are of important aspects for evaluating the rams' shear performance of subsea blowout preventer, the plastic deformation and fracture cross section of drill pipe are analyzed based on the plastic deformation theory and the hypothesis that the deformation process of drill pipe is a four-plastic hinge or an eight-plastic hinge mechanism, respectively, according to different ram structure configuration. The elastic-plastic deformation process of CT90 tube in the simulated shearing process is obtained, the final fracture cross section of CT90 tube is approximately a rhombus circle, which is agreeing with the analytical and experimental results. Furthermore, the structure parameters research shows that ram or pipe structures have limited effect on the peak/terminal value of pipe stress. The major length of rhombus circle increases first and then decreases with the increase of ram's blade mouth thickness, decreases with the increase of ram's V-shape angle and pipe wall thickness, while the minor length shows an opposite trend. The larger pipe outer diameter is, the greater major/minor length of rhombus circle is and the growth rate of major length is significantly faster than that of minor length.

Configuration spaces of hinged mechanisms, and their projections

Abstract Our subject is the geometry of planar hinged mechanisms. The article contains a formalization of basic concepts of the theory of hinged-lever constructions, as well as some information from real algebraic geometry needed for their study. We consider mechanisms with variable number of degrees of freedom and mechanisms that have more than one degree of freedom but each hinge of which moves with one degree of freedom. For the last type we find the dimension of the configuration space. We give a number of examples of mechanisms with unusual geometric properties and formulate open questions. Bibliography: 17 titles.

Mathematical Description and Study of the Vibration Deck of a Grain Sorting Machine

This article presents the results of a study of the vibrations of the deck of a pneumatic sorting machine. The purpose of this work is to describe the design and technological parameters of the soundboard for the implementation of a mathematical model of the technological process of the grain sorting machine. A kinematic study of the flat hinge mechanism of the deck of a grain sorting machine has been carried out, for which all geometric dimensions are known and the laws of motion of the leading link-the electric drive of the deck based on an asynchronous electric motor – have been determined. As a result, the following were determined: kinematic modes of deck vibrations under various technological conditions; the laws of motion of all links of the deck mechanism, displacement, speed and acceleration of the driven links; a mathematical model of the kinematic scheme of the deck of a grain sorting machine driven by an asynchronous electric motor has been developed.

Design of Pointing Control Mechanism for Spacecraft Antenna Communication

Satellite antennas are widely used in satellite communications and now have become an indispensable part of satellite. It affects and restricts the performance and functions of the entire wireless communication system. Flexible pointing and low power consumption are required for antennas installed on satellites, which makes the design of the pointing mechanism of the satellite antenna more challenging. This paper focuses on the design and analysis of the pointing control mechanism to help improve the flexibility of satellite communication. An optimized structure consisting of spring hinge mechanism, manipulator arm and universal adjustment mechanism is proposed. The material selection and mechanical analysis are also made. Finally, the pointing angle is described based on the mathematical model of the pointing control mechanism.

Wind-induced collapse mechanism and failure criteria of super-large cooling tower based on layered shell element model

Many wind-induced collapse events of super-large cooling tower have been taken place in history. Existing norms are limited within local excessive strength or buckling failure of the tower body, but ignore the follow-up phenomena after the general continuous collapse caused by local damages. Hence, they are difficult to disclose the wind-induced collapse mechanism and failure mechanism of super-large cooling tower. A case study on the world highest (228 m) cooling tower under construction in Northwest China was carried out. Variations of multi-scale wall thickness and reinforcement ratio at different positions of the tower body were considered by the layered shell element modeling method. The wind loads on the cooling tower surface were acquired through a wind tunnel test of pressure measurement on the rigid body. Displacement and internal force responses of the tower body under typical wind speeds were analyzed by combining the incremental dynamic analysis (IDA), thus determining the critical wind speed. Three redistribution of internal forces mechanisms during collapse of tower body were extracted based on the stress variation indexes before and after the node failure. Moreover, the development paths of three collapse mechanisms among units with different thicknesses of the tower body were discussed. Finally, the wind-induced failure criteria of super-large cooling tower structure were proposed based on throat deformation of the tower body. Research results demonstrated that the layered shell element model could simulate the full process of collapse of super-large cooling tower effectively and a central damage area from the throat of windward side to the center of tower body was formed. Subsequently, a crack network was formed after diffusion of the damage area along the circumferential and meridian until the complete collapse. Three redistribution mechanisms of internal forces during the collapse of the super-large cooling tower were proposed, including the sliding surface mechanism, rotating hinge mechanism and slipping surface mechanism. The super-large cooling tower structure developed wind-induced failure and collapse when the deformation failure index is δ ≥ 1.5%. It is of great significance to the design and construction of super-large cooling towers.

Piezoelectric stick-slip actuators with flexure hinge mechanisms: A review

Piezoelectric stick-slip actuators (PSSAs) are famous for ultimate working condition adaptability, simple structure, and positioning accuracy. To meet the demand of industrial application, lots of PSSAs designed with flexure hinge mechanisms (FHMs-PSSAs) have been developed to realize the requirements of translational motion, rotational motion, multi-degree-of-freedom (multi-DOF) motion. The output performance of the FHMs-PSSAs has been greatly improved, including load capacity, speed, and accuracy; moreover, some approaches to solve the problem of the backward motion are provided as well. In this work, the working principle of FHMs-PSSAs is introduced, and the excitation signals applicable to FHMs-PSSAs are summarized. Based on the current research and development status, the progress of structure design of FHMs-PSSAs is introduced in accordance with translatory FHMs-PSSAs, rotary FHMs-PSSAs, and multi-DOF FHMs-PSSAs. Additionally, the developed analysis methods and design schemes to improve the performance are introduced, including theoretical analysis methods, consistency scheme of forward and reverse performance, suppression scheme of the backward motion, and improvement scheme of positioning accuracy. The significance of this work can be regarded as a further supplement to the previous review articles on the PSSAs, which will provide a reference and guidance for the future development of FHMs-PSSAs.

Configuration spaces of hinged mechanisms, and their projections

Предмет статьи - геометрия плоских шарнирных механизмов. Статья содержит формализацию основных понятий теории шарнирно-рычажных конструкций, а также сведения из вещественной алгебраической геометрии, необходимые для изучения шарнирных механизмов. Исследуются механизмы с переменным числом степеней свободы и механизмы с числом степеней свободы, большим единицы, у которых каждый шарнир движется с одной степенью свободы. Для последних механизмов полностью решен вопрос о размерности их конфигурационного пространства. Приведен ряд примеров механизмов с необычными геометрическими свойствами, сформулированы нерешенные вопросы. Библиография: 17 названий.

Concept of Convex Hinge Mechanisms for Self-Deployable Panels

Developing 2-dimensional large self-deployable panel structures with higher flatness, we proposed a convex hinge and investigated the folding properties by experimental model. In the experiments, two types of configurations of convex hinge were evaluated in the load testing with the Miura-ori folded panel structures. The result showed the performance of folding properties for convex hinges. Finally, possibility of convex hinges for applying 2-dimensional self-deployable structures were discussed.

Head-shield brooches of the Roman Iron Age from the Tarand cemeteries of the eastern Baltic

This study is dedicated to the head-shield brooches from the tarand cemetery area in Estonia, Latvia and lands west of the Izhora plateau. Its aim is to better understand their development through a combined typological, compositional and chronological analysis and explore their social role in the identity politics of the people wearing them. The compositional evaluation was supported with portable X-ray florescence spectrometry (XRF), to improve our understanding of the metal choices made by their ancient craftsmen. The typological study suggests that one of the earliest brooches found in the tarand cemetery area belongs to the Almgren 100 brooches, most of which have a semi-circular shield on the front part of the bow, a multiple-piece spring, and a triangular foot. The evidence suggests that they emerged in the 2nd century. Subsequently, a local form developed in the northeast part of the tarand cemetery area towards the end of the century. This local type has a squared-off foot, a multiple-piece spring construction, and a short semi-circular head-shield. Many were also tinned, meaning their colour was deliberately changed to a shiny silvery-white. During the 3rd century, a further group of locally produced head-shield brooches also emerged. They have a hinged mechanism, a knob, and a decorative rib at the end of the foot. These local brooches likely represented a regional style and aesthetic. They could have played a visual role in connecting the wearer to their affiliated group, or played a part in a differing social role within the society from which they came.

Multilinear model for progressive collapse response of reinforced concrete frames under penultimate column removal scenario

When local damage occurs due to unexpected events, compressive arch action (CAA) and catenary action (CTA) increase the progressive collapse resistance beyond the conventional plastic hinge mechanism. To investigate the progressive collapse behavior, large-scale structural tests and/or finite element analysis are performed, which are time-consuming and requires in-depth professional knowledge. In the present study, a multilinear model was developed to evaluate the progressive collapse resistance of moment sub-frames after the removal of a penultimate column. To estimate the load-carrying capacity and corresponding deformation at each mechanism, the effects of boundary condition, and the geometric and material properties of the beam section on the structural performance were considered. The validity of the proposed method was verified by comparison with the existing test results of moment sub-frames under progressive collapse. Further, a parametric study was performed to investigate the effects of concrete strength, reinforcement ratio, beam section size, and beam span on the progressive collapse resistance of the substructure. The analysis results showed that increasing the beam depth or beam top rebar ratio significantly increased the progressive collapse resistance.

Influence of composite floor slab on seismic performance of steel plate shear walls

Steel plate shear walls (SPSWs) consisting of unstiffened thin steel plates attached to the horizontal and vertical boundary steel elements are often used as the lateral force-resisting systems in buildings. The presence of composite floor slabs may not only alter the force demands on the boundary elements but also influence the failure mode of SPSW systems under seismic loading. This study addresses this research gap through experimental investigation of a single-story single-bay SPSW with floor slab subjected to constant gravity load and gradually increasing reversed cyclic lateral displacement. A ductile detailing of beam-column joint has been proposed as an alternative to the conventional reduced beam sections. The test specimen demonstrated a stable hysteretic response up to 5.5% story drift without significant reduction in the lateral strength. The proposed connection ensured the desired hinge mechanism and high ductility of the SPSW specimen. Additionally, numerical analysis of SPSW systems with and without composite slabs has been conducted to predict their load-resisting capacities and modes of failure under lateral loading. The presence of the floor slab increased the axial load demand on the vertical boundary element and the shear deformation demand on the horizontal boundary elements of the SPSW system.

A fast and accurate method for the seismic response analysis of reinforced concrete frame structures considering Beam-Column joint deformation

Many previous investigations of reinforced concrete (RC) frame structures have demonstrated that beam-column joints may experience significant nonlinearities under earthquake excitations. However, most available analysis methods assume that the joint region remains rigid. Because joint failure may result in strength and stiffness losses and even induce structural collapse, it is difficult for an analytical model with a rigid joint assumption to obtain an accurate prediction of the structural nonlinear response. The behavior of a joint is mainly affected by the shear deformation of the joint core and bond-slip of beam longitudinal reinforcements in the joint. Although many different types of modeling approaches have been presented to effectively represent the behavior mechanism of beam-column joints, the introduction of joint models inevitably increases the complexity of the analytical model of the global structure and the effort of the solution process. Therefore, achieving highly efficient analysis on the premise of accurately predicting the seismic response of RC frame structures is still a topic that deserves investigation. This study presents an efficient analysis method for the accurate evaluation of the nonlinear response of RC frames considering the effect of beam-column joint deformation based on the concept of local inelasticity separation. The proposed method captures the bond-slip behavior at beam ends by adding inelastic rotation hinge mechanisms to the ends of the existing inelasticity-separated fiber beam-column model and uses a sliding hinge mechanism to simulate the inelastic shear response of the joint core. A small number of additional inelastic degrees of freedom that are separated from the global displacement degrees of freedom of the structure is introduced to describe both the inelastic rotation behavior and the inelastic deformation of the proposed bond-slip hinge mechanism and the sliding hinge mechanism. Consequently, the Woodbury formula can be utilized for nonlinear iterative solutions to avoid updating the global stiffness matrix, thus significantly improving the computational efficiency. The exactness of the proposed method is verified against experimental data, and its application is illustrated through a seismic response analysis example.

The risk factors for mechanical complication in endoprosthetic reconstruction of knee osteosarcoma

BackgroundThe increased limb survival rates and higher functional demands have also increased the mechanical complication rates of megaprostheses. This study aimed to analyse possible risk factors which can predispose patients to mechanical complications. MethodsPatients with knee osteosarcoma referred to our clinic from 1992 to 2014 were investigated retrospectively. The patients who underwent surgical resection and endoprosthetic reconstruction with at least 5 years of follow up were analysed. The revision of the megaprosthesis due to a mechanical complication was accepted as an endpoint. The possible risk factors, including cement usage, implant material, joint mechanism, neoadjuvant radiotherapy, and anatomical localization of the lesion, were analysed for any association with mechanical complication rates. ResultsA total of 118 patients were included for final analysis. The average age was 24.5 years (standard deviation ±10.1, range: 15–64). Mechanical complication rate was 22% which included 19 aseptic loosenings and seven implant failures. The average time to mechanical complication was 32.5 months. Overall, 5-year implant survival was 78%. Multiple regression analysis revealed that cement usage is an independent risk factor for mechanical complication (P = 0.007). Although the 5-year implant survival was higher in rotating hinge and titanium implants compared with fixed hinge and cobalt chrome, the multiple regression model did not yield a correlation with mechanical complication rates. ConclusionCemented implants showed significantly higher mechanical complication rates compared with cementless ones in this series of knee osteosarcoma patients who underwent megaprosthetic reconstruction. Hinge mechanism and implant material did not have a significant effect on mechanical complication rates.