Large Moment Research Articles

Role of secondary shear-layer vortices in the development of flow asymmetry on a cone–cylinder body at high angles of incidence

Vortex asymmetry develops on slender bodies at high angles of incidence, leading to large side-forces and yaw moments even in symmetrical flight conditions. In the present experimental study, the flow over a slender body consisting of a conical forebody and a cylindrical aftbody is studied at high angles of incidence at low speeds. Experiments consisted of force measurements using a six-component strain gauge balance and velocity field using Particle Image Velocimetry. Results show that a pair of counter-rotating vortices develop nearly symmetrically over a polished cone but become asymmetric over the cylinder. Several secondary shear-layer vortices develop at the cone–cylinder junction and over the cylinder due to sharp turning angle, surface imperfections, and joints. These secondary shear-layer vortices then merge with the primary vortex pair, leading to the flow asymmetry. The flow characteristics and side-forces vary significantly when the conical forebody is rotated about its axis of symmetry and set to different azimuthal positions. The results strongly suggest that a change in the geometry at the cone–cylinder junction and surface imperfections present on the cylindrical aftbody play an important role in determining the overall flow-asymmetry and the magnitude of side-forces generated on the slender body at high angles of incidence.

Biomechanical Posture Assessment of Salted Fish Industry Workers in West Aceh

Salted fish is dried fish that is preserved by adding salt as the preservative medium. The process of production starts with cleaning, salting, boiling, drying, sorting, and packing. The length and complexity of the process lead to an increase in the risk of MSDs and posture complaints among the workers. This study aimed to find out the factors that caused the complaints with the biomechanical posture method. Six subjects were measured for the tension at erector spinae and the moment at (lumbar 5 sacrum 1) L5-S1 vertebral joint created by body segments and load, the calculation of the workers’ body segment weight, the distance of the body’s center point to the lumbar 5 sacrum 1 (L5-S1), and biomechanics at L5-S1. The largest body segment weight was found at the cleaning station, which dealt with the process of manually lifting the fish, with a bodyweight value of 70 kg, Wtrunk: 350 N, Whead: 58.8 N, Warm: 35.7 N and Wload: 300 N. The farthest distance from the body’s center point to L5-S1 was found at the drying station, which deals with the process of drying the fish, with values of the distance of head (dhead): 54.78 cm, distance of trunk (dtrunk): 59.26 cm, distance of arm (darm): 67.39 cm and distance of box (dbox): 86.11 cm. The largest moment in force on L5-S1 was found at the packing station, which deals with the fish transferring and packaging process, with the value of the moment of force at 5351.86 N and 4215.28 N. Therefore, it is suggested that the salt fish industry finds solutions, re-designing the work station, decreasing the lifting load, and producing proper equipment to assist workers during labor to improve their safety and health.

Centrifuge Modeling of the Impact of Local and Global Scour Erosion on the Monotonic Lateral Response of a Monopile in Sand

Abstract The majority of offshore wind turbines are founded on large-diameter, open-ended steel monopiles. Monopiles must resist lateral loads and overturning moments because of environmental (wind and wave) actions, whereas vertical loads tend to be comparatively small. Recent developments in turbine sizes and increases in hub heights have resulted in pile diameters increasing rapidly, whereas the embedment length to diameter ratio (L/D) is reducing. Soil erosion around piles, termed scour, changes the soil strength and stiffness properties and affects the system’s load resistance characteristics. In practice, design scour depths of up to 1.3D are routinely assumed during the turbine lifetime; however, the impact on monopiles with low L/D is not yet fully understood. In this article, centrifuge tests are performed to assess the effect of scour on the performance of piles with low L/D. In particular, the effect of combined loads, scour type (global, local), and depth are considered. A loading system is developed that enables application of realistic load eccentricity and combined vertical, horizontal, and moment loading at the seabed level. An instrumented 1.8-m-diameter pile with L/D = 5 is used. A friction-reducing ball-type connection is designed to transfer lateral loads to the pile without inducing any rotational pile-head constraint, which is associated with loading rigs in tests of this nature. Results suggest that vertical and lateral load interaction is minimal. Scour has a significant impact on the lateral load-bearing capacity and stiffness of the pile, leads to increases in bending moment magnitude along the pile shaft, and lowers the location of peak pile bending moment. The response varies with scour type, with global scour resulting in larger moments than local scour. The size of the local scour hole is found to have a significant impact on the pile response, suggesting that scour hole width should be explicitly considered in design.

Lateral dynamic bridge deck–pier interaction for ultra-high-speed Hyperloop train loading

The next generation of ultra-high-speed (UHS) trains, known as Hyperloop and TransPod, are aerospace type vehicles designed to carry passengers. The UHS employs a vehicle capsule within a protected vacuum tube deck, supported by reinforced concrete piers (i.e. multi-span viaduct). The tube environment allows multiple UHS vehicles to run in parallel simultaneously (i.e. twin tube deck) where asymmetric train loading will result in a large dynamic unbalanced moment on the piers. Therefore, exploring the lateral dynamic interaction of bridge deck (twin tube) and piers under such an unbalanced moment is an extremely important factor for the analysis of viaducts under dynamic UHS train loading. Hence, this paper analytically addresses the dynamic bridge deck–pier interaction under UHS train loading for lateral vibration.

Suggestion for Search of Malononitrile (CH2(CN)2) in a Cosmic Object: Potential Spectral Lines

Though accurate laboratory studies of malononitrile (CH2(CN)2), a dinitrile molecule, have been carried out from time to time, and it has large electric dipole moment $$\mu = 3.735$$ D, its detection in a cosmic object is still awaited. Because of two equivalent hydrogen atoms, it has ortho and para species. In order to obtain information about some potential spectral lines of malononitrile, which may play important role for its identification in a cosmic object, we have carried out Sobolev large velocity gradient (LVG) analysis, using spectroscopic data, for each of the species. We have calculated energies of 250 lower rotational levels (up to 98 cm–1) for each species and the Einstein $$A$$ and $$B$$ coefficients for 1231 (ortho) and 1229 (para) radiative transitions between the levels. The collisional rate coefficients, required for the analysis, are calculated with the help of a scaling law. Very exciting results are obtained; we have analyzed 6 potential transitions for each species of CH2(CN)2, which may play important role in the identification of malononitrile in a cosmic object.

Synchronous generators for traction mechanisms

This article shows the principle of operation, experimental characteristics, comparison with other types of generators, functional diagrams of an electric generator set based on a field regulated reluctance machine. Attention is drawn to the high specific performance and favorable performance characteristics of these power generating sets. The simplicity of the design ensures high manufacturability of the electric machine, the non-contact design in combination with a “cold” winding-free rotor increases the reliability of the bearings and the entire machine, the ability to make the rotor massive (the rotor poles and the shaft are from one solid billet) significantly increase it strength and lateral stiffness. Also it allows obtaining high angular velocities and large moment overloads. Small control powers along the excitation circuit with a sufficiently high speed of this channel contribute to the achievement of high accuracy of maintaining a given voltage at favorable mass and dimensional parameters of the electric power plant.

Growth and characterization of novel Ir1–xCrxO2 thin films

Novel Ir1–xCrxO2 thin films have been prepared by reactive co–sputtering deposition. Composition, structure and electric and magnetic behavior have been analyzed by different techniques including EDX, XRR, XRD, SQUID magnetometry, electrical resistivity and XANES and XMCD spectroscopies. Despite the difficulty in growing CrO2 by physical deposition techniques, an Ir1–xCrxO2 solid solution phase could be achieved for 0 ≤ x ≤ 0.8, where the oxidation state of Cr is found to remain as 4+. Both the electrical and the magnetic behavior are shown to starkly depart from those of the parent IrO2 (paramagnetic metal) and CrO2 (half–metal ferromagnet) compounds. In particular, they show a semiconducting behavior, dρ/dT < 0 and giant magnetic coercivity at low temperatures. XMCD reveals a significant contribution of Ir to the magnetic response of the Ir1–xCrxO2 films. In addition, the nature of the magnetic moment of the Ir4+ ion (〈ml〉/〈ms〉 = 0.09) is completely different from the large orbital moment that is a hallmark of insulating Ir4+ oxides. This suggests a Cr–induced magnetic moment, which is a remarkably surprising result for an oxide.

Vehicle contact network based on fluid coupling analysis of load of operational status detection device

Based on the analysis of aerodynamic load and structural strength of the vehicle contact network monitoring device, the distribution of aerodynamic moments and surface pressure of the monitoring device is calculated by means of fluid-solid coupling. The calculated load is applied to the surface of the device for structural analysis, mainly to investigate the maximum deformation and maximum equivalent stress of the device. The study found that air flow separation occurred above the ear region when driving forward, the pressure was higher, and the air flow below the ear region flowed around the ear region. The pressure difference between the upper and lower ears produced a downward force of about 150N in a single ear region, and produced a large rolling moment, after checking its connection strength with the central body to meet the requirements for use.

Structural evaluation of Félix Candela’s 8-sided hyperbolic paraboloidal umbrellas

Structural artist Félix Candela pioneered the 8-sided hyperbolic paraboloidal (hypar) umbrella by introducing a parabolic discontinuity bisecting each quadrant of the classical 4-sided form. While artistically striking, such structures have never been rigorously examined from a structural engineering perspective. This paper formulates equations governing the geometry of 8-sided hypars, facilitating the in-depth analysis and comparison against their more common 4-sided variants via finite element modeling. A parametric investigation based on two historical case studies identified that 8-sided umbrellas exhibit larger deflections and stresses relative to 4-sided renditions, thus rebuking Candela’s hypothesis concerning the improvement to structural efficiency offered by the parabolic fold. While corner deflections and principal stresses generally decrease with increasing curvature, the discontinuity present in 8-sided forms disrupt the flow of internal forces, resulting in stress concentrations at the parabolic apex manifesting as large moment demands. However, it was demonstrated that 8-sided hypars exhibit increased resistance to shell buckling over 4-sided variants as revealed through a simplified analytical approach.

Recovery From a Forward Falling Slip: Measurement of Dynamic Stability and Strength Requirements Using a Split-Belt Instrumented Treadmill

Aim: Falls commonly occur from trips and slips while walking. Recovery strategies from trips and backward falling slips have been extensively studied. However, until recently, forward falling slips (FFSs) have been considered less dangerous and have been understudied. This study aimed first to create an application to realistically simulate FFSs using a split-belt instrumented treadmill and then to understand the biomechanical requirements for young adults to recover from an FFS.Methods: We developed a semi-automatic custom-made application on D-Flow that triggered FFSs by briefly and unexpectedly increasing the speed (a = 5 m·s−2) of the right belt during stance. To validate the protocol, we tested against criteria defined for an ecologically and experimentally valid FFS: unexpected occurrence of the slip, increased foot velocity, forward loss of balance during the slip and consistent perturbation timing. We evaluated the recovery strategies of 17 young adults by measuring dynamic stability, joint moments and ground reaction force (GRF) vector angles before, during and on 15 steps following the FFS.Results: The application successfully triggered FFSs, according to the criteria we defined. Participants' balance returned to normal for a minimum of three consecutive steps in 10.9 (7.0) steps. Recovery from the FFSs was characterised by larger hip flexor and knee extensor moments to support the centre of mass during the slip, and a longer first recovery step with large hip extensor moments to arrest the fall followed by large knee extensor moments to raise and advance the centre of mass into the next step (p < 0.001 compared with normal gait). Subsequent steps progressively returned to normal.Conclusion: This is the first study to experimentally simulate FFSs meeting the aforementioned criteria, and to measure their effects on the dynamic balance and kinetic parameters. The split-belt instrumented treadmill proved a promising tool to better study the mechanisms of falls and recovery. The required large hip and knee joint moments generally agree with findings on trips and backward falling slips and provide an indication of the functional capacities that should be targeted in fall-prevention interventions. These findings should be used to better understand and target the mechanisms of balance loss and falls in older adults following FFSs.

Differences in muscle mechanics underlie divergent optimality criteria between feeding and locomotor systems.

Tetrapod musculoskeletal diversity is usually studied separately in feeding and locomotor systems. However, direct comparisons between these systems promise important insight into how natural selection deploys the same basic musculoskeletal toolkit-connective tissues, bones, nerves, and skeletal muscle-to meet the differing performance criteria of feeding and locomotion. Recent studies using this approach have proposed that the feeding system is optimized for precise application of high forces and the locomotor system is optimized for wide and rapid joint excursions for minimal energetic expenditure. If this hypothesis is correct, then it stands to reason that other anatomical and biomechanical variables within the feeding and locomotor systems should reflect these diverging functions. To test this hypothesis, we compared muscle moment arm lengths, mechanical advantages, and force vector orientations of two jaw elevator muscles (m. temporalis and m. superficial masseter), an elbow flexor (m. brachialis) and extensor (m. triceps- lateral head), and a knee flexor (m. biceps femoris-short head) and extensor (m. vastus lateralis) across 18 species of primates. Our results show that muscles of the feeding system are more orthogonally oriented relative to the resistance arm (mandible) and operate at relatively large moment arms and mechanical advantages. Moreover, these variables show relatively little change across the range of jaw excursion. In contrast, the representative muscles of the locomotor system have much smaller mechanical advantages and, depending on joint position, smaller muscle moment arm lengths and almost parallel orientations relative to the resistance arm. These patterns are consistent regardless of phylogeny, body mass, locomotor mode, and feeding specialization. We argue that these findings reflect fundamental functional dichotomies between tetrapod locomotor and feeding systems. By organizing muscles in a manner such that moment arms and mechanical advantage are relatively small, the locomotor system can produce broad joint excursions and high angular velocities with only small muscular contraction. As such, the anatomical organization of muscles within the limbs allows striding animals to move relatively rapidly and with minimal energetic expenditure. In contrast, the anatomical configuration of muscles in the feeding system, at least m. superficial masseter and m. temporalis, favors their force-producing capacity at the expense of excursion and velocity.

Wearable Shoulder Exoskeleton with Spring-Cam Mechanism for Customizable, Nonlinear Gravity Compensation.

Wearable, mechanically passive (i.e. spring-powered) exoskeletons may be more practical and affordable than active, motorized exoskeletons for providing continuous, home-based, antigravity movement assistance for people with shoulder disability. However, the biomechanical moment due to gravity is a nonlinear function of shoulder elevation angle and, thus, challenging to counteract proportionally across the shoulder elevation range of motion with a spring alone. We designed, fabricated, and tested an integrated spring-cam-wheel system that can generate a nonlinear moment to proportionally compensate for the expected antigravity moment at the shoulder. We then incorporated the proposed system in a benchtop model and a novel wearable passive cable-driven exoskeleton that was intended to counteract half of the gravitational moment during shoulder elevation movements. The rotational moment measured from the benchtop model closely matched the theoretical moment during simulated positive shoulder elevation. However, a larger moment (up to 12.5% larger) was required during simulated negative shoulder elevation to stretch the spring to its initial length due to spring hysteresis and friction losses. The wearable exoskeleton prototype was qualitatively tested for assisting shoulder elevation movements; we identified several aspects of the prototype design that need to be improved before further testing on human participants. In future studies, we will quantitatively evaluate human kinematics and neuromuscular coordination with the exoskeleton to determine its suitability for assisting patients with shoulder disability.

Numerical Simulation of Cu-Al-Mn Endodontic Instruments under Bending and Torsional Conditions

This study focuses on the development of endodontic instruments manufactured from Cu-Al-Mn shape memory alloys (SMAs) which are more economical and easier to process as compared to conventional NiTi SMAs. Finite element analysis of three different numerical instruments was performed using material parameters of Cu-Al-Mn and conventional superelastic NiTi. Flexural and torsional stiffness of these instruments with the resulting von Mises stresses were evaluated under bending and twisting based on the ISO 3630-1 specification. All the studied Cu-Al-Mn endodontic files exhibited superior flexibility and lower reaction stresses as compared to NiTi endodontic files during bending, resulting from their low elastic modulus and starting stress value for the martensitic transformation. However, low torsional stiffness and high von Mises stress values related with the high angular displacement were obtained for Cu-Al-Mn endodontic instruments under torsional loading. Geometric differences of different models have been an important factor in adjusting the stiffness of endodontic instruments. Consequently, it was determined that Cu-Al-Mn SMA could be used as an alternative material in the manufacture of endodontic files that have large cross-sectional area and moment of inertia.

Magnetic and electronic properties of layered Sr2NiO2Cl2 with square planar coordination

Local coordination geometry is crucial in determining the physical properties of transition metal compounds. In this work, we report a detailed density functional theory study on the magnetic and electronic properties of layered Sr2NiO2Cl2, which possesses an unusual square planar coordination. Due to the crystal field and spin splitting, Ni 3d electrons fully occupy the dxz, dyz, and dxy orbitals, while partially occupy the dz2 and dx2-y2 states, leading to the high spin state of Ni2+ ions and strong antiferromagnetic in-plane nearest-neighbor exchange interaction J1. Thus, Sr2NiO2Cl2 is predicted to exhibit a G-type magnetic ground state, which all nearest-neighbor magnetic moments are antiparallel to each other in the NiO2 plane. A band gap is opened irrespective of the specific magnetic state since the unique square planar crystal field splitting. Finally, large orbital moments and giant easy-plane magnetocrystalline anisotropy energy are obtained, which is again related to the unique coordination environment.

Bulk and Nanocrystalline Cesium Lead-Halide Perovskites as Seen by Halide Magnetic Resonance.

Lead-halide perovskites increasingly mesmerize researchers because they exhibit a high degree of structural defects and dynamics yet nonetheless offer an outstanding (opto)electronic performance on par with the best examples of structurally stable and defect-free semiconductors. This highly unusual feature necessitates the adoption of an experimental and theoretical mindset and the reexamination of techniques that may be uniquely suited to understand these materials. Surprisingly, the suite of methods for the structural characterization of these materials does not commonly include nuclear magnetic resonance (NMR) spectroscopy. The present study showcases both the utility and versatility of halide NMR and NQR (nuclear quadrupole resonance) for probing the structure and structural dynamics of CsPbX3 (X = Cl, Br, I), in both bulk and nanocrystalline forms. The strong quadrupole couplings, which originate from the interaction between the large quadrupole moments of, e.g., the 35Cl, 79Br, and 127I nuclei, and the local electric-field gradients, are highly sensitive to subtle structural variations, both static and dynamic. The quadrupole interaction can resolve structural changes with accuracies commensurate with synchrotron X-ray diffraction and scattering. It is shown that space-averaged site-disorder is greatly enhanced in the nanocrystals compared to the bulk, while the dynamics of nuclear spin relaxation indicates enhanced structural dynamics in the nanocrystals. The findings from NMR and NQR were corroborated by ab initio molecular dynamics, which point to the role of the surface in causing the radial strain distribution and disorder. These findings showcase a great synergy between solid-state NMR or NQR and molecular dynamics simulations in shedding light on the structure of soft lead-halide semiconductors.

Wind Turbines Optimal Operation at Time Variable Wind Speeds

The wind turbine’s operation is affected by the wind speed variations, which cannot be followed by the wind turbine due to the large moment of the power plant’s inertia. The method proposed in this paper belongs to the wind turbine power curves (WTPC) approach, which expresses the power curve of the permanent magnet synchronous generator (PMSG) by a set of mathematical equations. The WTPC research papers published before now have not taken into consideration the total power plant inertia at time-variable wind speeds, when the wind turbine’s optimal operation is very difficult to be reached, and its efficiency is thus threatened. The study is based on a wind turbine having a large moment of total inertia, and demonstrates, through extensive simulation results, that the optimal values of the PMSG’s power can be determined based on the kinetic motion equation. This PMSG’s optimal power represents an ideal time-varying curve, and the wind turbine should be controlled so as to closely follow it. For this purpose, proportional integral (PI) and proportional integral derivative (PID) type-based control methods were implemented and analyzed, so that the PMSG’s power oscillations could be reduced, and the PMSG’s angular speed value made comparable to the optimal one, meaning that the wind turbine operates within the optimal operation area, and is efficient. The simulations are actually the numerical solutions obtained by using the Scientific Workplace simulation environment, and they are based on the wind speed measurements collected from a wind farm located in Dobrogea, Romania.

Effect of Load Cases and Hanger-Loss Scenarios on Dynamic Responses of the Self-Anchored Suspension Bridge to Abrupt Rupture of Hangers

Self-anchored suspension bridges with large prestressed girders have proven to be suitable bridge structures where external anchorage systems cannot be easily provided. However, these bridges cannot overcome the major limitation that their hangers may suddenly break under hazardous circumstances, which may cause the potential risk of progressive collapse. In this paper, the effects of hanger-loss scenarios and load cases on the structural performance of the self-anchored suspension bridge are studied. To conduct the investigation, several issues related to the nonlinear dynamic simulation are presented. The results obtained from a case study on a concrete self-anchored suspension bridge show that the dynamic effects caused by the hanger-breakage event are heavily dependent on the duration of the breakage process. Compared to the sudden breakage of a single hanger, the asymmetrical loss of two hangers can cause a large torsional moment in the girder and tensile stress in hangers. The influence of load cases on the structural dynamic responses is significant, while the effect on the dynamic amplification factor (DAF) corresponding to hangers and the stiffening girder is not obvious. In addition, it is shown that structural robustness can be better enhanced with double-type hangers than with single-type hangers. Finally, several useful recommendations are proposed for concrete self-anchored suspension bridges to improve structural safety and avoid progressive failure of hangers.

Stable control of the high-speeding magnetically suspended rotor based on extended state observer and two-degree freedom internal model control for control moment gyros with serious moving-gimbal effects

For a magnetically suspended control moment gyro (MSCMG), which is an ideal attitude actuator for its large outputting control moment and fast response, the moving-gimbal effects due to the coupling between the moving gimbal and high-speeding rotor will make the magnetically suspended rotor (MSR) unstable. To improve control precision, both the dynamic model of MSR and the feedback linearization control are done to decouple tilting motion, and poles of the system are reconfigured to reduce control error. To suppress the varying disturbance moments caused by moving-gimbal effects, an extended state observer (ESO) is originally designed to estimate and compensate them timely and accurately. To improve system robustness, a two-degree freedom internal model control (2-DOF IMC) is researched to suppress model error. Compared with existing proportional integral derivative (PID) control method, simulations done on a single gimbal MSCMG with 200 N.m.s angular momentum indicated that this presented control method with ESO and 2-DOF IMC can suppress the moving-gimbal effects more effectively and make the rotor suspension more stable.

Seismic control of a single-tower extradosed railway bridge using the E-Shaped steel damping bearing

An extradosed bridge is a hybrid structure that combines the main elements of the classic cable-stayed bridge and continuous girder bridge. Almost all extradosed bridges have the main girder transversely restrained at the pier locations, which may cause extremely large transverse shear force and bending moment on bridge substructures during strong earthquakes. This study thoroughly investigates the efficacy of using the E-shaped steel damping bearing (ESSDB) for lateral seismic control of a prototype extradosed railway bridge. Firstly, high-fidelity finite element models are developed for nonlinear time history analyses for both the ESSDB isolated bridge and two conventional non-isolated configurations (i.e., rigid frame system and continuous system). Parametric sensitivity study is then carried out, which indicates a tendency of decreasing transverse deck displacements and increasing pier base transverse forces with the increase of the ESSDB yield force. The optimal ESSDB yield force is thus selected mainly based on a tradeoff between maximizing the structural force reduction and limiting the deformation demand of the ESSDB. Finally, through detailed comparisons of bridge seismic responses with the two non-isolated cases, it shows that the ESSDB can significantly reduce the transverse seismic force demands in bridge substructures, at a cost of a moderate increase in superstructure displacements and formation of permanent inelastic deformation in the ESSDB. It is concluded that the ESSDB can provide a simple and efficient solution to the transverse seismic control of the extradosed railway bridge.

Electronic Structure and Magnetic Anisotropy of Single-Layer Rare-Earth Oxybromide.

The discovery of intrinsic magnetism in two-dimensional (2D) limit has triggered increasing investigations in layered magnetic materials. However, most of the available candidates involves 3d transition metals, while the layered rare-earth magnetic materials are largely unexplored at present. Here, we proposed a series of 2D rare-earth magnetic semiconductors REOBr (RE = Tb, Dy, Ho, Er and Tm) with large magnetic moments and magnetic anisotropy energies using the PBE + U method. Our calculations indicate a half-metallic meta-stable state and a low-energy semi-conducting ground state in these 4f single-layers, which can be characterized by the location of the two-fold degenerate x(x2 – 3y2) orbital. The dynamical stability of single-layer REOBr is further confirmed using phonon dispersions. The predicted energy gaps ranging from 2.47 to 4.26 eV decrease with the atomic number of the rare-earth element. Meanwhile, very large spin moments and orbital moments up to 6.018 and 2.872 μB are found, which seem to be insensitive to the magnetic state. Furthermore, the magnetic anisotropy energies are evaluated and understood by a fourth-order non-uniaxial anisotropy mode. Diverse anisotropy energy landscapes including easy cone, easy plane, and easy axis are found, and an extremely high magnetic anisotropy energy of about 8 meV per RE atom is found in the single-layer DyOBr. Our investigations provide a unique insight into layered rare-earth magnetic materials and suggest the single-layer REOBr as competing candidates for low-dimensional data storage applications.