Torque Moment Research Articles

A new simple method for shell vibration analysis with initial stress accounting

This paper presents a simple semi-analytical approach for free vibration of cylindrical shell with initial prestress based on equivalent load method and the Donell-Mushtari theory. In most practical applications, shells are subjected to static loadings causing internal stress field. The presence of such initial forces like internal pressure, axial force, centripetal force and torque moment significantly affects the natural frequency spectra. According to Calladin’s equivalent load method initial stress field create additional curvatures and can be added as additional terms to the basic equations. The results of presented method agree well with experimental data found in the literature. Effects of elastic support stiffness, the shell length and radius to thickness ration on natural frequencies are investigated.

Diagrid systems coupled with closed- and open-section shear walls: Optimization of geometrical characteristics in tall buildings

Nowadays diagrid systems are employed worldwide for the realization of tall buildings since they allow to achieve remarkable architectural effects while providing an efficient mechanism to limit lateral displacements. Furthermore, being composed by an assembly of trusses on the exterior of the structure, they are suitable for optimization procedures if changing geometrical parameters, such as the inclination of the external diagonals. Such optimization procedures are generally carried out by means of Finite Element models, focusing mostly on diagrid lateral rigidity. In the last few decades, in order to perform the structural analysis of tall buildings, an analytical formulation, called General Algorithm (GA), was developed by some of the authors, which is much less time-consuming than FE calculations, while allowing to capture important insights on the structural behavior. Moreover, a matrix-based method has been recently proposed for the analysis of diagrid systems, which was shown to be suitable for insertion into the GA and able to provide information on the diagrid lateral and torsional flexibility. In this contribution, we analyze the structural behavior of external diagrid systems coupled with closed-section (CS) and open-section (OS) shear walls using the GA. The analysis was performed by considering lateral forces and torque moments distributed along the height of the building. By the GA, defined the building height and plan geometry, the optimal inclination of the external diagonals was sought, in order to minimize lateral displacements and torsional rotations. The effect of the shear wall type, i.e. CS or OS, was also investigated on the structural response, and it was found to have a significant impact on the torsional rotations.

Developing a Stand for Evaluating Technical Condition of Volumetric Hydraulic Drives with a Hydraulic Loading Device

Introduction. The article deals with the development of a device for evaluating technical condition on of volumetric hydraulic drives made in Russia and abroad at repair and service centres. Materials and Methods. The study uses the statements of theoretical mechanics and hydrodynamics, the basic principles of mechanisms and machines production. For technical condition evaluating of volumetric hydraulic drives, the method of hydraulic loading of hydraulic motor was applied. Reliability of results was confirmed during experimental settings of the hydraulic loading device stand. Results. A stand design with the hydraulic loading device was developed and put into practice for new technical condition evaluating of volumetric hydraulic drives, made in Russia and abroad, at repair and service centres. A property of the stand is the use of the hydraulic loading method when the torque (braking) moment on the shaft of the tested hydraulic rotor is created using a hydraulic machine. The stand consists of data processing and measurement units. The data processing unit is based on a multifunctional data acquisition board connected with a personal computer. The structure of the data measurement unit includes a frequency converter connected to an electric motor, a drive shaft for connecting the shaft of the tested hydraulic pump; hydraulic system having a hydraulic tank; suction, control, drain, and discharge lines and reversible flow chokes installed in discharge lines and connected with the hydraulic pump and hydraulic rotor; loading device with the reversible hydraulic pump, drive shaft joined with the shaft of the tested hydraulic motor. Additionally, reversible throttle flow meters are connected via special ports and electric lines to the data acquisition board. The developed stand allows evaluating the technical condition of most widespread models of volumetric hydraulic drives used in modern agricultural and road construction equipment. The stand is characterized by good energy efficiency, simplicity of design, low costs, good technical characteristics that make it competitive. Discussion and Conclusion. The new stand design with the hydraulic loading device allows implementating of the dynamic testing methodology and guarantees high accuracy of evaluating the technical condition of the most widespread Russian and foreign volumetric hydraulic drives at repair and service centres. Further improvement of the evaluating the technical condition of volumetric hydraulic drives is related to the development of specialized software for processing and analysing test results in real-time.

EXPERIMENTAL INVESTIGATION OF WIND ENERGY PLANT WITH HELICOIDAL ROTOR

The article is devoted to design and investigation of a helicoidal wind rotor in the wind tunnel, which is a modification of the Darrieus rotor – the most promising rotor type for vertical axis wind turbines. The graphs of power and rotation of the investigated wind generator depending on the incoming air flow speed are obtained. Investigation of the helicoidal rotor in a large wind tunnel has shown that the helicoidal rotor type has a high potential for use in vertical axis wind turbines. The high cut in speed of the incoming air flow is caused by the phenomenon of "sticking" of the axial generator with steel cores, as well as by the absence of an additional starting Savonius rotor, which could create the initial torque moment at rhe low speed of the incoming air flow.Iit is necessary to enlarge diameter of the generator and to reduce the air gap between the magnets and the stator to increase electric power.

The influence of upper-body mechanics, anthropometry and isokinetic strength on performance in wrist-spin cricket bowling

ABSTRACTDelivering a cricket ball with a wrist-spin (WS) bowling technique is considered one of the game’s most difficult skills. Limited biomechanical information exists for WS bowlers across skill levels. The purpose of this study was to compare biomechanical, isokinetic strength and anthropometric measures between elite (12) and pathway bowlers (eight). Data were collected using a motion analysis system, dynamometer and a level-two anthropometrist. A regression analysis identified that performance was best explained by increased wrist radial deviation torque and longitudinal axis rotational moments at the shoulder and wrist. From back foot impact (BFI) to ball release (BR), elite bowlers rotated their trunks less, experienced less trunk deceleration resulting in a more front-on position and increased pelvis rotation angular velocity. They also displayed an increased shoulder internal rotation moment as the upper arm moved from external into internal rotation and was a major contributor in the subsequent differences observed in the distal segments of the bowling limb. Anthropometric differences were observed at the wrist and finger joints and may be used to form the basis for talent identification programmes. This study highlights the important contribution to bowling performance of the musculature responsible for producing long axis rotations of the bowling limb.

Simulating Torque Converter on a 3 GTs Fishing Vessel using Computational Fluid Dynamics

Torque converter is needed to reduce the difference distance on an engine power curve and propeller operating load curve. Torque converter works by removing and cutting the flow of power from engine to transmission shaft automatically in order to adjust with fluctuative propeller load. Torque converter works on a fluid clutch principal hence it has ability to absorb and reduce excessive torque moments. This research aims to determine the effect of impeller distance against dynamic characteristics of torque converter on a 3 GT fishing vessel. Based on the designed torque converter dimension, a simulation using computational fluid dynamics (CFD) in an ANSYS 16.0 simulation software was conducted. The simulation was done on three distances between impellers i.e. 2.5 mm, 5 mm, and 7.5 mm and on five rotations i.e. 600 rpm, 1000 rpm, 1400 rpm, 1800 rpm, and 2200 rpm. Information obtained from the CFD simulation includes: pressure and shear stress distribution on impeller, flow velocity on the torque converter shell, torque value, as well as maximum transmission power of torque converter. The result shows that the ideal impeller gap for the 3 GTs fishing vessel from the dynamic characteristics parameter of torque converter is 7.5 mm.

Dynamic balancing of drive mechanism of roller forming installation with energy balanced drive

In order to increase reliability and durability dynamic balancing of drive mechanism of roller forming installation with energy balanced drive is considered. When simulating the process of balancing the drive mechanism, two tasks of dynamic balancing are solved: balancing of inertia forces applied in cents of masses of movable links, and balancing of torque moment brought to the axis of rotation of the drive shaft resulting from the action of inertia forces. At the same time all kinematic characteristics of forming trolleys of the installation are defined, functions of kinetic energy of each element and the whole system, forces of inertia of each element of the installation and total force of inertia, total moment from action of inertia forces are recorded. On the basis of Lagrange equations of the second kind, the equation of the motion of the installation is compiled and the generalized force and driving moment on the shaft of the drive motor are determined. Unbalance of drive mechanism is estimated by maximum and standard values of total inertia force and torque total moment from action of inertia forces, dimensionless coefficients expressing a ratio of the standard values of the total inertia force and inertia forces reduced to the center of mass of the apparatus; acting on each trolley, and ratio of standard values of moment from action of inertia forces of the whole mechanism and components of moment from action of inertia forces of individual elements. It has been found that in an energetically balanced drive unit, the best balancing of the inertia forces applied in the centers of mass of the links and the torque brought to the rotation axis of the drive shaft resulting from the action of the inertia forces is observed at the value of the displacement angle of the cranks 120 0 . The received results can be used further for the specification and improvement existing engineering by method of calculation of driving mechanisms of cars of roller formation both at design/designing stages and in the modes of real operation.

Integrated design of control allocation and triple-step control for over-actuated electric ground vehicles with actuator faults

Over-actuated electric ground vehicles (EGVs) with four individually activated in-wheel motors can satisfy the requirements for the total wheel torque and yaw moment through control allocation (CA), which improves not only the driving flexibility, active safety and energy efficiency but also the probability of in-wheel motor faults due to the significantly increased system complexity and number of actuators. This paper studies the development of an active fault-tolerant control (AFTC) strategy that integrates CA and triple-step control (TSC) to produce a nominal feedback controller and simultaneously handle actuator faults. The closed-loop system under control is stabilized with input-to-state stability (ISS). A theoretical architecture of the proposed AFTC strategy for over-actuated EGVs is presented with a robust CA design and novel TSC with adaptive control compensation (ACC). In addition, a numerical iterative algorithm is proposed for the implementation of the ACC, and the convergence condition is given. The effectiveness of the proposed scheme is validated for a high-fidelity full-vehicle model constructed by the commercial software veDYNA.

Parameter Identification of Induction Motor by Using Cooperative-Coevolution and a Nonlinear Estimator

Induction motors are one of the critical industrial drivers due to its simplicity, inexpensiveness, and high resistance. Such motors have a nonlinear model divided into two electrical and mechanical equations in terms of modeling. Knowing the values of electric parameters and mechanical moment of inertia is critically important for speed controlling and induction motors’ position. In many algorithms, electric parameters can be obtained by the locked rotor and unloaded tests, conducting these methods in laboratory would probably cost a lot of time and money. In this paper electrical parameters and moment of inertia are used approximately, without doing the above test by currents, voltages, and motor speed sampling in motor normal operation. This paper applies cooperative co-evolution method to remove certain costly tests that are required for induction motors. Two identification algorithms are suggested for all electrical parameters and moment of inertia. All inductances and resistances which are the two input parameters measured in electric equations using Cooperative-Coevolution algorithm. Mechanical model estimated the moment of inertia and load torque by using a nonlinear method based on Lyapunov. Computerized numerical simulations show that electric parameters, moment of inertia, and load torque were properly estimated by integrating the two smart and classic methods. The results show that the stator inductance error is about 1% and rotor inductance error is around 20%. Rotor and stator resistance error and self-Inductance is also less than one percent.

Critical Output Torque of a GHz CNT-Based Rotation Transmission System Via Axial Interface Friction at Low Temperature.

It was discovered that a sudden jump of the output torque moment from a rotation transmission nanosystem made from carbon nanotubes (CNTs) occurred when decreasing the system temperature. In the nanosystem from coaxial-layout CNTs, the motor with specified rotational frequency (ωM) can drive the inner tube (rotor) to rotate in the outer tubes. When the axial gap between the motor and the rotor was fixed, the friction between their neighbor edges was stronger at a lower temperature. Especially at temperatures below 100 K, the friction-induced driving torque increases with ωM. When the rotor was subjected to an external resistant torque moment (Mr), it could not rotate opposite to the motor even if it deformed heavily. Combining molecular dynamics simulations with the bi-sectioning algorithm, the critical value of Mr was obtained. Under the critical torque moment, the rotor stopped rotating. Accordingly, a transmission nanosystem can be designed to provide a strong torque moment via interface friction at low temperature.

Parameterized optimization analysis with finite elements, using ANSYS®, of a reference point under a torque action

To determine the elastic/plastic deformation value of the part, we used Ansys R19.0 software(CAE), to simulate a torque moment applied to the functional area part, which provided the information set about the part behavior. The mold of the part has 4 cavities, and the part material is a polyamide. Having a requirement imposed by the customer on the drawing, we considered this finite element analysis it is necessary before start manufacturing the molding and starting injection the parts to demonstrate that the customer requirement is achievable. The results obtained from the analysis with finite elements in ANSYS R19 showed that the constructional part could not fulfill the design requirement, namely to withstand a torque of 4500Nmm the part being fixed in the hole with a diameter of 2.5 mm. After analyzing the results, the client will have to modify the current drawing based on the results obtained by us, namely to reduce the torque value from 4500Nmm to 4000.3 Nmm.

Young Athletes Upper Knee Muscular Strength Isokinetic Testing / Izokinetičko testiranje snage natkolene muskulature mladih sportista

This research main goal is to determine differences in maximum upper knee musculature torque moment of judo, football and handball players. For the needs of the research, 30 respondents were tested, of which 10 were football, 10 handball players and 10 judo athletes. Testing was conducted in Isokinetic Diagnostic Cabinet of the Provincial Institute for Sports and Sports Medicine in Novi Sad on the isokinetic dynamometer “Easytech prima DOC”. Significant differences were noted in the maximum torque moment of both legs extensors force (PTQR, PTQL) between judo athletes and football players, in favor of judo. Obtained results between observed groups can be attributed to the various sports branches training processes specificities, i.e. performing certain techniques in the sport itself

Full-Turn Actuator with Cylindrical Wedge Mechanism

Features of existing designs of actuators of ball valves are considered. An essentially new type of actuator capable of rotating 360° is presented. Data on the torque and specific moment of the proposed full-turn actuator are presented.

Load Torque and Moment of Inertia Identification for Permanent Magnet Synchronous Motor Drives Based on Sliding Mode Observer

In this paper, a load torque observer and two moment of inertia identification methods are developed for permanent magnet synchronous motor drive systems. First, the load torque identification method is proposed based on sliding mode observer, in which the mismatches of moment of inertia, electromagnetic torque, and viscous friction are all considered. It is analyzed that the chattering phenomenon will be well weakened if appropriate observer parameters are chosen. Second, based on the property that the mismatch of the moment of inertia will cause the load torque observation error, two types of moment of inertia identification methods, called direct calculation (DC) method and proportional integral (PI) regulator method, are presented to identify the moment of inertia. In addition, the identification errors of the DC and PI regulator methods are also analyzed theoretically. Simulation and experimental results show that compared with the conventional identification method of the moment of inertia, the proposed DC and PI methods have improved estimation accuracy. Moreover, the presented load torque observer also has high observation precision and fast convergence speed.

Pengaruh Jumlah Sudu Terhadap Kinerja Turbin Savonius

Savonius wind turbines are wind turbines that canoperate at low wind speeds, this type of turbine is very suitable tobe used in several places in Indonesia. The research aims toimprove the performance of the Savonius wind turbine withvariations in the number of turbine blades as well as variations inthe velocity of wind speed. The research method wasexperimental where wind turbine testing was carried out withvariations in the number of turbine blades with number of 2, 3and 4 blades, other variations carried out were wind speed at 3.5;4,5; 5.5 and 6.5 m/s. The study results show that the 2-bladeturbine produces greater rotation, but the torque moment islower than the 3 and 4 blade turbines, this can be seen in the lowefficiency of the 2 blade turbine at low wind speeds with highloading. At 3.5 m / s wind turbines 2 blade turbines haveefficiency that tends to be the same as 3 and 4 blade turbines upto 0.5 N but at loads of 0.6 - 1.2 N 2 blade turbines have lowerefficiency, while at wind speeds of 4.5 - 6.5 m / s 2 blade turbineshave greater efficiency than turbines 3 and 4 blades up to a loadof 1.2 N but if the load is added then the efficiency of 2-bladeturbines can be smaller than efficiency 3 and 4-blade.

An energy-efficient torque-vectoring algorithm for electric vehicles with multiple motors

In electric vehicles with multiple motors, the individual wheel torque control, i.e., the so-called torque-vectoring, significantly enhances the cornering response and active safety. Torque-vectoring can also increase energy efficiency, through the appropriate design of the reference understeer characteristic and the calculation of the wheel torque distribution providing the desired total wheel torque and direct yaw moment. To meet the industrial requirements for real vehicle implementation, the energy-efficiency benefits of torque-vectoring should be achieved via controllers characterised by predictable behaviour, ease of tuning and low computational requirements. This paper discusses a novel energy-efficient torque-vectoring algorithm for an electric vehicle with in-wheel motors, which is based on a set of rules deriving from the combined consideration of: i) the experimentally measured electric powertrain efficiency maps; ii) a set of optimisation results from a non-linear quasi-static vehicle model, including the computation of tyre slip power losses; and iii) drivability requirements for comfortable and safe cornering response. With respect to the same electric vehicle with even wheel torque distribution, the simulation results, based on an experimentally validated vehicle dynamics simulation model, show: a) up to 4% power consumption reduction during straight line operation at constant speed; b) >5% average input power saving in steady-state cornering at lateral accelerations >3.5 m/s2; and c) effective compensation of the yaw rate and sideslip angle oscillations during extreme transient tests.

Numerical Estimation of Glass Fiber Reinforced Plastic Propeller Performance Using Rigid and Flexible Model

Composite materials have offered some improvements on the performance of hydrodynamic and structures of marine constructions. The high strength to weight and stiffness to weight ratio might be tailored through the exploitation of the fiber orientation in order to reduce the load and the stress distribution of the structure. In order to fully explore the performance of the developed glass fiber reinforce plastics (GFRP) B-series propeller for traditional purse seine boat in the North Coast of Central Java, the aim of the research is focused on the comparison of the rigid and the flexible model adopted for the simulation analysis of the propeller performance. The thrust force, the torque moment and the efficiency of the two propeller models are discussed.

CFD Validation of a Model Wind Turbine by Means of Improved and Delayed Detached Eddy Simulation in OpenFOAM

With the ongoing increase in the size of wind turbines, experimental investigations have become more complicated and expensive. Therefore, computational models have proven to be a viable solution for design purposes. This article aims to validate CFD simulations of an experimental model wind turbine (MoWiTO 1.8) using Delayed Detached Eddy Simulation (DDES) and Improved DDES (IDDES) turbulence modelling approaches. For the purpose of validation, integral quantities (such as power, thrust, torque and blade-root bending moment in the flapwise direction) measured in the wind tunnel are compared with numerical results obtained with OpenFOAM. In general, the computational results show a very good agreement with the measurements for most of the monitored quantities. In particular, the blade-root bending moment presents the largest difference, taking into account that the simulation assumes the turbine blades are rigid. Nevertheless, the simulation does achieve in recreating the turbulent behavior as can be evidenced by the Power Spectral Density graphs, and the wake’s velocity measurements. In general, the IDDES turbulent model achieves a better agreement to the experimental results, while maintaining a very similar computational time as the DDES model.

Using fidget spinners in teaching some physics concepts

In this article, the use of fidget spinners, which have recently become popular with students, is recommended to increase student motivation for the learning of certain topics in physics and their understanding of them, namely: friction, moment of inertia, torque and conservation of angular momentum.

Dihedral Angle Calculations To Elucidate the Folding of Peptides through Its Main Mechanical Forces.

This study reports a general method to calculate dihedral angles (φ and ψ) of a given amino acid sequence, focusing on potential energy and torque moment concepts. By defining these physical measures in relation to the chemical interactions that occur on each single amino acid residue within a peptide, we analyze the folding process as the result of main mechanical forces (MMFs) exerted in the specific amino acid chain of interest. As a proof of concept, Leu-enkephalin was initially used as a model peptide to carry out the theoretical study. Our data show agreement between calculated Leu-enkephalin backbone dihedral angles and the corresponding experimentally determined X-ray values. Hence, we used calcitonin to validate our MMF-based method on a larger peptide, i.e., 32 amino acid residues forming an α-helix. Through a similar approach (although simplified with regard to electrostatic interactions), the calculations for calcitonin also demonstrate a good agreement with experimental values. This study offers new opportunities to analyze peptides' amino acid sequences and to help in the prediction of how they must fold, assisting in the development of new computational techniques in the field.