Torque Moment Research Articles

Principles and biomechanical response of normal gait cycle to measure gait parameters for the alignment of prosthetics limb: A technical report.

The limb amputations caused due to emergent incidents of trauma injuries and vascular diseases currently represent crucial global problems. The patients/amputees with limb amputation who lost the residual limb (knee-ankle foot system) must depend on the prosthetic limb. Prosthetic clinicians and technicians have attempted to develop optimal limb prosthetics that will enhance the ability and functional elements of the patients/users. However, the amputees still do not gain the same level of comfort and functional stability as compared to normal limbs (without amputation). Thus, to provide that comfort and stability, proper construction with accurate positioning and alignment of constructed prosthetic limb is crucial to reconstitute these amputees/patients to do their activities for daily life. The objective of technical report is to provide the brief summary about basic principle and biomechanics regarding gait analysis, construction, and alignment of prosthetic limb during gait cycle. The study also summarized the kinematics and kinetic biomechanical response of prosthetic limbs to assess the biomechanics of limb prosthetics, socket assembly principle, gait parameters, and static and dynamic alignment during walking. The basic principle of positioning and alignment with different flexion and torque moment at hip, knee, and ankle joint has been analyzed.

Modelling the Prioritisation of Technical Objects Using the EPN Indicator

The objective of this article is to analyse and evaluate the effectiveness of predictive maintenance for machines performing key functions within a production structure. This article presents a methodology for determining the Equipment Priority Number (EPN), calculated based on parameters such as energy consumption, the criticality of machines in the value stream, and their impact on the continuity of the supply chain. The experimental implementation of a system for monitoring operational parameters—including current consumption, vibrations, and torque moments—enabled the prediction of potential failures and the planning of maintenance actions, which contributed to improving operational stability and reducing the risk of unplanned downtime. The obtained results confirm the effectiveness of the proposed methodology and demonstrate that a predictive maintenance system supported by the EPN indicator enables accurate prioritisation of maintenance activities in an actual production system. The findings also show that implementing the EPN algorithm allows for more precise prioritisation in highly customised production environments. Furthermore, the analysis of the collected data suggests the potential for further optimisation through the integration of data-driven diagnostics and artificial intelligence methods, which could enhance the efficiency and competitiveness of the system. This study’s conclusions provide a foundation for advancing predictive maintenance methods in industrial production.

Comparative Analysis of Displacements and Stress Produced by Square and Rectangular Bracket Slot With Incremental Torque: A Finite Element Analysis Study.

This study aimed to perform a comparative analysis of stresses and displacements with incremental torque on the maxillary incisors and surrounding cortical bone using conventional metal brackets with rectangular slots and passive self-ligating brackets with square slots using finite element analysis (FEA). An in vitro FEA study was conducted, in which a three-dimensional (3D) model of the maxilla was built using ANSYS softwareversion 18 (ANSYS Inc., Canonsburg, PA). The conventional McLaughlin, Bennet, and Trevisi (MBT) bracket (3M Unitek, Monrovia, CA) of 0.022 × 0.028-inch slot with a 0.019 × 0.025-inch rectangular stainless steel (SS) archwire (model 1) was compared with the Pitts 21™ self-ligating bracket system (OC Orthodontics, McMinnville, OR) of 0.021 x 0.21-inch slot with a 0.020 × 0.020-inch square SS archwire (model 2) at incremental torques of 5°, 10°, 15°, and 20°. The von Mises stress was evaluated at the maxillary incisors and surrounding cortical bone. The torque moment, tipping angle, and displacement of the maxillary incisors were also measured and compared between the bracket systems. The highest torque expression of 13.8 N-mm was observed in model 2, compared to a torque expression of 10.68 N-mm in model 1. The torque expression increased in both models from 0°to 20°. There was a play of 6.2°at 20°torquein model 2, whereas it was 9.32°​​​​​​​play in model 1. The torque expressions were better for the lateral incisors than for the central incisors. Increased incremental torque was associated with increased proclination of the incisors, and this movement was more pronounced for the central incisor and model 1. Furthermore, it was revealed that the stresses on the cortical bone and teeth were higher in model 2 than in model 1. It was concluded that the Pitts 21™ passive self-ligating system produced better torque expression and less play with square SS archwire compared to conventional brackets with rectangular SS archwire.

Bio-functionalization of fillers with natural phytic acid for sustainable flame-retardant agents for natural rubber composites

The current challenge for sustainable flame retardants has led to innovative approaches, including the utilization of natural substances to enhance the fire resistance of elastomer composites. This paper presents the design of eco-friendly hybrid flame-retardant additives based on mineral fillers (hydrotalcite (LDH) and sepiolite (SEP)) modified with aminosilane (APTS) and phytic acid (PA) for natural rubber (NR) biocomposites. The synergistic effects of the PA and silanized mineral fillers resulted in NR composites with improved thermal, mechanical, and barrier properties, as well as increased flame retardancy. Importantly, it was proven that direct in-situ application of PA into elastomer cured with sulphur-based crosslinking systems is ineffective, due to its negative effect on the curing process (significantly reducing torque moment). Binding the PA onto silanized fillers enabled the creation of hybrid additives that leverage the flame-retardant benefits of PA without compromising the other properties of the polymer. The addition of PA-modified fillers to NR reduced the heat release rate (HRR) by around 40 %, indicating outstanding flame retardancy. This work makes a significant contribution and expands the understanding of using eco-friendly natural compounds to reduce the flammability of sulfur-cured elastomers.

Torque moments and stress analysis in two passive self-ligating brackets across different incisor inclinations: A 3-dimensional finite element study

ObjectiveTo compare torque expression characteristics between rectangular slot (0.022″ x 0.028″) Damon Q passive self-ligating brackets (Ormco, Glendora, Calif) and square slot (0.021″ x 0.021″) Pitts 21 brackets (OC Orthodontics) using 0.019″ x 0.025″ Stainless Steel and 0.020″ x 0.020” Titanium Molybdenum alloy wires at various incisal inclinations using finite element analysis. The null hypothesis was that there were no differences in torque expression in both tested groups. MethodsReporting guidelines for in-silico studies using finite element analysis in medicine (RIFEM) were used. Damon Q and Pitts 21 brackets were scanned and 3D models generated. Brackets were placed on a 3-D model of a maxillary central incisor with its long axis inclined at 0⁰,5⁰,10⁰,15⁰ and 20⁰ to the occlusal plane. Final 0.019″ x 0.025″ SS and 0.020″ x 0.020” TMA archwires were inserted into slots of both tested brackets. Geometric models were converted into finite element models. Material properties were assigned for involved structures with automatic meshing performed by software. Torque movements were simulated with the FE program Ansys Space claim R 22. ResultsTorque moment values, torque expression and Von - Mises stress was higher in Pitts 21 than Damon Q at all inclination angles. There was a gradual increase in the magnitude of values with decrease in incisal inclination. ConclusionSquare slot passive self-ligating brackets show superior torque expression characteristics as compared to rectangular wire-rectangular slot combinations. The FEM results should be validated with in-vivo studies in order to confirm the findings.

A unified linear intrinsic alignment model for elliptical and disc galaxies and the resulting ellipticity spectra

Alignments of disc galaxies were thought to result from tidal torquing, where tidal field of the cosmic large-scale structure exert torquing moments onto dark matter haloes, determining their angular momentum and ultimately the orientation of galactic discs. In this model, resulting intrinsic ellipticity correlations are typically present on small scales, but neither observations nor simulations have found empirical evidence; instead, simulations point at the possibility that alignments of disc galaxies follow a similar alignment model as elliptical galaxies, but with a weaker alignment amplitude. In our article we make the case for the theory of linear alignments resulting from tidal distortions of the galactic disc, investigate the physical properties of this model and derive the resulting angular ellipticity spectra, as they would appear as a contribution to weak gravitational lensing in surveys such as Euclid’s. We discuss in detail on the statistical and physical properties of tidally induced alignments in disc galaxies, as they are relevant for mitigation of alignment contamination in weak lensing data, comment on the consistency between the alignment amplitude in spiral and elliptical galaxies and finally, estimate their observability with a Euclid-like survey.

Analytical Solutions of the 3-DOF Gyroscope Model

The motion of a rigid body (a gyroscope) is one of the key issues in classical mechanics. It remains a significant challenge, as evidenced by its extensive practical implementations in various scientific disciplines and engineering operations. It is important to obtain analytical solutions, as they provide solutions that depend directly on the system’s parameters, which can be definitively interpreted. The coupling of numerical and analytical solutions allows for a more precise representation of the real phenomenon. The main objective of the article was to formulate analytical solutions for the motion of a Cardan suspension gyroscope subjected to controlling torque moments. Analytical solutions for the proposed mathematical model were developed using the Laplace transform and Green’s function. Subsequently, they were validated by numerical tests. The obtained analytical solutions are universally applicable, regardless of the type of controlling moments.

Study on Vehicle-Bridge Coupled Vibration of Curved Girder Bridges under Different Road Surface Grades

This study explores the impact of different levels of road surface smoothness on the dynamic response of bridges. By conducting a detailed analysis under five different conditions of road surface smoothness, the mechanisms by which road surface irregularities affect the dynamic characteristics and safety performance of bridge structures are revealed. The research employs the finite element simulation method to compare and analyze the changes in key dynamic indicators such as vertical displacement, torsional angle, torque, and bending moment of bridges under different grades of road surface smoothness. The results indicate that a decrease in road surface smoothness significantly increases the dynamic response of bridges. The findings provide important reference information for bridge engineers in the design and maintenance of bridges.

Influence of wind gusts on aeroelastic loads of NREL 5MW wind turbine

This study employs blade-resolved computational fluid dynamics simulations to investigate the aero-elastic loads on a yawed NREL 5MW wind turbine subject to full and partial wind gusts. A novel spatial gust representation, tailored towards application to large eddy simulations, is introduced. This methodology permits the injection of gusts with customizable spatial dimensions inside the flow domain. Simulations are conducted with gusts having the same diameter as the turbine rotor, half rotor diameter, and asymmetric impact with respect to the center of rotation of the turbine. Simulations of the turbine under yawed conditions are also considered. The flow characteristics are reported using contours and iso-surfaces of velocity magnitude and Q-criteria. Insights into the load characteristics of the turbine are described using torque, thrust, and root bending moments. This research highlights that partial gust impact contributes to noteworthy load fluctuations and blade tip deformations, stemming from the imbalance in force distribution across the rotor plane.

Generalized Deplanation Hypotheses for Linear and Angular Deformations in Reinforced Concrete Structures under Combined Torsion and Bending

Statement of the problem. The analysis of the deplanation hypothesis for linear and angular deformations in reinforced concrete in bending with torsion has been carried out. Results. A simple new method from the method of grids has been developed for complex functions under the combined action of bending and torsion. Diagrams of linear and angular deformities and a new hypotheses have been analyzed. Complex functions have been found to determine the linear and angular deformations, bending and torque moments in the compressed area of concrete. The author has found the projection coefficients of linear and angular deformations using diagrams of compressed concrete and main reinforcement. Deplanations from a special geometric figure of deformations in a complex function have been found. There are vectors of several triangles and gradients where the proportions of a hypotenuse, cathetuses and vectors have been derived. Conclusions. It is also important that similar relative values can be obtained for any vectors. A field of small squares have been plotted and jumps from lateral, normal and other cracks appear have been determined. Fillings of the deformation (stress) diagrams have been obtained for the analysis of the moments in bending with torsion using simple expressions or in a full form. The research on the complex function of linear and angular deformations and the approximation of a function from Timoshenko-Goodyear have been carried out. The error of the deformations value of using the complex function at the points under study is 2% and is 7% at any points of the cross section.

Biomechanical Simulation of Orthodontic En-Bloc Retraction Comparing Compound Technique and Sliding Mechanics Using a HOSEA Robotic Device.

En-bloc retraction is a common procedure in orthodontic therapy. The application of palatal root torque moments is required to control incisor inclination during retraction, yet studies comparing forces and moments with respect to different mechanics are lacking. This study aimed to investigate the forces and moments during orthodontic en-bloc retraction using a robotic biomechanical simulation system, comparing two distinct approaches: (I) compound technique [stainless steel (SS) combined with nickel-titanium (NiTi)] using industrially pretorqued retraction-torque-archwires (RTA) in combination with NiTi closed coil springs; (II) conventional sliding mechanics using SS archwires with manually applied anterior twist bends in combination with elastic chains. Two dimensions (0.017" × 0.025" and 0.018" × 0.025") and ten archwires per group were investigated using 0.022" slot self-ligating brackets. Kruskal-Wallis tests with a significance level of α = 0.05 were conducted. The biomechanical simulation showed that en-bloc retraction was characterized by a series of tipping and uprighting movements, differing significantly regarding the examined mechanics. Collateral forces and moments occurred in all groups. Notably, RTA exhibited fewer extrusive forces. The most bodily movement was achieved with the compound technique and the 0.018" × 0.025" RTA. Sliding mechanics exhibited maximum palatal root torque moments of more than 20 Nmm, exceeding recommended values.

Incisor torque expression characteristics in two passive self-ligating brackets placed at different heights. A finite element investigation

ObjectiveThis study investigated torque expression in maxillary incisors using two passive self-ligating bracket types (Damon Q and Pitts 21) placed at different heights using the Finite element method. Materials and methodsTwo passive self-ligating brackets, Damon Q (Ormco, USA) and Pitts 21 (OC Orthodontics, USA) were 3D modeled using micro-computed tomography. Damon Q (0.022ˮ x 0.028″ slot size) and Pitts 21 (0.021ˮ x 0.021″ slot size) brackets were placed on a maxillary central incisor at predetermined vertical heights. Arch wires of size 0.019ˮ x 0.025″ stainless steel (Damon Q) and 0.020ˮ x 0.020” Titanium Molybdenum (Pitts 21) were placed in the bracket slots. ResultsPitts 21 brackets showed higher torquing moments at all bonding heights as compared to Damon Q brackets. The minimum torquing moment was 9.03Nmm at 5 mm for Damon Q and the maximum torquing moment was 14.92Nmm for Pitts 21 at a bracket bonding height of 8 mm. Total deformation for Pitts 21 at a height of 5 mm from the incisal edge was 0.61 × 10−6mm as compared to that of Damon Q which was 0.41 × 10−6mm. Lowest Von Mises stress values were at 27.07 MPa in Damon Q brackets at a bracket height of 5 mm from the incisal edge. Highest Von Mises stress values were 36.80 MPa for Pitts 21 brackets at a bracket height of 8 mm from the incisal edge. ConclusionPitts 21 brackets exhibited superior torquing characteristics compared to Damon Q. Total deformation in Pitts 21 was higher than Damon Q at all tested bracket bonding heights.

Formula Student car chassis – research on the torsional stiffness

In the article, the torsional stiffness of a formula student's space frame was analyzed. The article mainly focuses on the comparison of the stiffness between different frame designs, which were used in three consecutive formula student cars designed by the weracing™ team as well as a comparison of the result of two calculation methods. The calculations were made in computer-aided engineering software, i.e. ABAQUS dedicated to analyzing Finite Elements models. The assumption for analysis was to check the rotation of the frame after applying a 5000 Nm load. The torsional load was introduced by first fixed the four rear bulkhead joint and then subsequently applying a force couple to the upper front wishbone mounts. Having a distance between joint from the central line and torque moment, the force for specific nodes can be calculated. The calculation for each model was performed. The obtained differences result from the construction of frames and applied methods of calculations.

Review of Methods for Determining the Moment of Inertia and Friction Torque of Electric Motors

Review of Methods for Determining the Moment of Inertia and Friction Torque of Electric Motors

Efficacy of in-house clear aligner therapy mechanics on root torque: an in-vitro study

Abstract Background This study aimed to evaluate the torque effectiveness of different attachment types and power ridges used in clear aligner therapy (CAT) on the upper lateral incisors. Methods A typodont model simulating oral conditions was developed. Two hundred lateral incisor samples were divided into five groups based on attachment types and clear aligner modifications: no attachments (NA), horizontal ellipsoid attachment (HEA), vertical ellipsoid attachment (VEA), buccal power ridge (BPR), and buccal and palatal power ridge (BPPR). Subsequently, a 5° palatal torque moment was applied to the lateral incisors. In-house clear aligners were inserted, and 3D scanning was performed after each aligner step. Post-treatment 3D models were compared with pre-treatment models. The lateral incisors were assessed for torque, tipping, and rotational movements. Results The HEA group (41.6%) and the BPPR group (40.8%) showed significantly higher torque effectiveness than the NA group (20%) when 5° of torque was delivered. The planned movement was approximated when 1° and 2° of torque were applied in the NA group (114% and 98%, respectively). The NA and BPR groups showed the highest loss of anchorage. Conclusions When more than 3° of torque was applied, HEA and BPPR were more effective than NA in achieving the CAT’s planned torque of the upper lateral incisors, although with an efficacy rate of approximately 40%. Highlights It is challenging to achieve torque movement using CAT. When less than 3° of torque was required, additional mechanics were not necessary. BPPR and HEA showed higher effectiveness when 5° of torque was applied. The efficacy of BPR was similar to that of NA.

Determination of internal efforts in the base finite elements of SAFEM

The principles of calculating the internal efforts of a circular finite element in the semi-analytical finite element method (FEM) based on the obtained components of the stress tensor and the peculiarities of the approach associated with the use of the moment scheme of the finite element (FEM) are considered. Formulas for determining longitudinal, shear forces, bending and torque moments have been obtained.
 A special place, among the variety of objects considered with the help of analytical and numerical methods, is occupied by bodies of revolution of complex shape and cross-sectional structure, formed by the movement of some creative surface along a closed or opened line without breaks. The selected geometric class is used as natural structures of nodes and details in construction of mechanical engineering. The sufficiently wide distribution of the specified forms in the construction and machine-building industries, on the one hand, and the possibility of significantly simplifying the solving relationships by taking into account their geometric features, on the other hand, provide a basis for the development and use of various modifications of the finite element method (FEM). The semi-analytical finite element method (SAFEM) is one such approach that has gained widespread use for solving problems whose objects are prismatic bodies and bodies of revolution of complex shape and cross-sectional structure. Due to the introduction of additional hypotheses that do not reduce the accuracy of the approximation, the representation of deformations and stresses in physical terms and in accordance with the moment scheme of the finite element (MSFE), on the one hand, it is possible to avoid the time-consuming procedure of numerical integration over the cross-sectional area of the finite element (FE), on the other hand - maintain the high efficiency of 3D discretization.
 Despite the large number of publications devoted to the semi-analytical method of finite elements, the question of determining internal forces, which are often component factors of the strength criteria laid down in state building codes, is inappropriately neglected. The use of SAFEM in combination with МSFЕ creates some mathematical features of calculating internal longitudinal, shearing forces and moments.

Cascaded 2D Micromirror with Application to LiDAR.

This paper introduced a novel approach to enhance the vertical scanning angle of a large aperture 2D electromagnetic micromirror through the utilization of a cascaded torsional beam design. The primary objective was to increase the vertical scanning angle without compromising the robustness, which was achieved by optimizing the trade-off between the rotation angle and the first mode of resonant frequency. The cascaded design provides flexibility to either increase the outer frame's rotation angle without sacrificing torsional stiffness or enhance the torsion beam's stiffness while maintaining the same rotation angle, thus elevating the first-mode resonant frequency and overall robustness. The effectiveness of the cascaded design was demonstrated through a comparative study with a non-cascaded 2D micromirror possessing the same aperture size, torque, and mass moment of inertia. Theoretical analysis and finite-element simulation are employed to determine critical parameters such as the stiffness ratio between the cascaded torsion beams, and to predict improvements in the scanning angle and primary resonant frequency brought by the cascaded design. Prototypes of both cascaded and non-cascaded designs are fabricated using a flexible printed circuit board combined with Computer numerical control (CNC) machining of a Ti-alloy thin film, confirming the superior performance of the cascaded 2D micromirror. The cascaded design achieved vertical scanning angles up to 26% higher than the traditional design when both were actuated at close resonance frequencies. Additionally, the micromirror was successfully integrated into a 3D LiDAR system. The light detection and ranging (LiDAR) system was modelled in Zemax OpticStudio to find the optimized design and assembly positions.

Milling Force Modeling Methods for Slot Milling Cutters

The slot milling cutter is primarily used for machining the tongue and groove of the steam turbine rotor, which is a critical operation in the manufacturing process of the steam turbine rotor. It is challenging to predict the milling force of a groove milling cutter due to variations in rake, rake angles and cutting speeds of the main cutting edge. Firstly, based on a limited amount of experimental data on turning, we have developed an equivalent turning force model that takes into account the impact of the rounded cutting edge radius, the tool’s tip radius and the feed rate on tool’s geometric angle. It provides a more accurate frontal angle for the identification method of the Johnson–Cook material constitutive equation. Secondly, the physical parameters, such as shear stress, shear strain and strain rate on the main shear plane, are calculated through the analysis of experimental data and application of the orthogonal cutting theory. Thirdly, the range of initial constitutive parameters of the material was determined through the split Hopkinson pressure bar (SHPB) test. The objective function was defined as the minimum error between the theoretical and experimental values. The optimal values of the Johnson–Cook constitutive equation parameters A, B, C, n and m are obtained through a global search using a genetic algorithm. Finally, the shear stress is determined by the governing equations of deformation, temperature and material. The axial force, torque and bending moment of each micro-segment are calculated and summed using the unit cutting force vector of each micro-segment. As a result, a milling force prediction model for slot milling cutters is established, and its validity is verified through experiments.

Force-Controlled Biomechanical Simulation of Orthodontic Tooth Movement with Torque Archwires Using HOSEA (Hexapod for Orthodontic Simulation, Evaluation and Analysis).

This study aimed to investigate the dynamic behavior of different torque archwires for fixed orthodontic treatment using an automated, force-controlled biomechanical simulation system. A novel biomechanical simulation system (HOSEA) was used to simulate dynamic tooth movements and measure torque expression of four different archwire groups: 0.017″ x 0.025″ torque segmented archwires (TSA) with 30° torque bending, 0.018″ x 0.025″ TSA with 45° torque bending, 0.017″ x 0.025″ stainless steel (SS) archwires with 30° torque bending and 0.018″ x 0.025″ SS with 30° torque bending (n = 10/group) used with 0.022″ self-ligating brackets. The Kruskal-Wallis test was used for statistical analysis (p < 0.050). The 0.018″ x 0.025″ SS archwires produced the highest initial rotational torque moment (My) of -9.835 Nmm. The reduction in rotational moment per degree (My/Ry) was significantly lower for TSA compared to SS archwires (p < 0.001). TSA 0.018″ x 0.025″ was the only group in which all archwires induced a min. 10° rotation in the simulation. Collateral forces and moments, especially Fx, Fz and Mx, occurred during torque application. The measured forces and moments were within a suitable range for the application of palatal root torque to incisors for the 0.018″ x 0.025″ archwires. The 0.018″ x 0.025″ TSA reliably achieved at least 10° incisal rotation without reactivation.

Research on low speed control position observer for accumulator electric locomotive PMSM

The PMSM of accumulator electric locomotive is generally controlled without position sensor, but the traditional position observer has the low speed observation accuracy, and the nonlinear factors of many mechanical parameters, such as torque feedback and moment of inertia, interfere with the low dynamic performance of the motor control system. A position observation model based on the nonlinear expansion observer is designed. The position observation model is constructed by using the relationship among the speed of the motor, the position angle of the rotor and its angular acceleration as well as the nonlinear function. Because it can avoid measuring the load torque and using the nonlinear expansion observer to estimate the uncertain disturbance, it is easy to realize. The simulation results show that the position observer can make the electric locomotive run stably under low speed control and has good low speed dynamic performance.