Torsional Shaft Research Articles

Hierarchical distributed model predictive control of hybrid wind and solar generation system

Distributed networked generation (DNG), which incorporates renewable energy and clean energy into information networks, has become increasingly important for modern power systems. In DNG, wind power and solar power generation are considered as intermittent systems with multiple constraints. The coordinated optimization of the wind power and solar power generation can effectively meet the load demand while guaranteeing the safety of power grids by reducing the wear and tear of generating units and prolonging the lifetime of grids. This study aims to construct a hierarchical distributed model predictive control (HDMPC) for large-scale, geographically dispersed wind-solar power generation systems. In HDMPC, the upper layer utilizes an iterative distributed control strategy to coordinate the power dispatch. Thus, it attains economic objectives, including the reduction in the torsional shaft torque transmitted to the gearbox in the wind turbine system and the generation cost. The lower layer utilizes the supervisory predictive control to realize economic and tracking properties. HDMPC enables the plug-and-play of distributed energy through the coordinated optimization of subsystems. Simulation experiments validated the advantages of the proposed method, which can meet the demands of safe, reliable, highly efficient, flexible, and interactive microgrid controlling.

Influence of Emergency Load on the Residual Strain Value of Torsion ShaftsInfluence of Emergency Load on the Residual Strain Value of Torsion Shafts

Scope of the research: when operating the torsion shaft in alternating mode the emergency loads may occur, upon which the resulting stresses will exceed the yield strength of steel. In this case, the Bauschinger effect is exhibited, consisting in the reduction of the plastic deformation resistance of steel after preliminary plastic deformation of opposite sign. The studies of the Bauschinger effect aspects at the alternating torsion are practically not available. An effective way to improve elastic properties of steel is stress tempering. The purpose of this work has been to investigate the influence of the deformation value and the direction at stress tempering specimens of hardened medium-carbon Cr-Ni-Mo steel on the residual strain under alternating emergency load. Main results: it has been found out that after tempering with plastic deformation the manifestation of the Baushinger effect, when twisting the specimens to emergency angle in one direction and then in the reversed one, is of ambiguous character. This effect depends on the plastic deformation ratio of steel during heat treatment and on the direction of test strain. The anisotropy of properties observed constitutes an essential disadvantage for elastic elements operating under alternating loads. Practical significance: it has been found out that the lowest residual strain in the specimen is observed when the strain value during steel tempering corresponds to the deformation produced by emergency load. The obtained results will be useful in development of torsion shaft processing technology that provides reducing of anisotropy properties under alternating emergency load.

REPAIRING THE MAIN SHAFT OF DRYER TOASTER

Introduction. The sources of damage and wear of the main shaft of the drier toaster are analyzed. The repair know-how and welding operations execution limitations which must be considered when developing the technique providing the restoration of the structure performance features are studied. The work objective is to develop a technique of repair without dismantling for the main toaster shaft. To solve the task, a design repair structure was installed, and postwelding operations that meet the engineering and regulatory requirements for this structure were performed.Materials and Methods. In “Kompas 3D” software, the following models were developed: integral shaft (project shaft design); damaged shaft as a result of long-term operation (more than 15 years); and damaged shaft with a welded repair structure. Numerical simulation of the stress-strain state (SSS) was carried out.Research Results. Software for the computational modeling of the repair structure SSS is developed. The repair shaft structure in which the maximum stresses do not exceed the shaft stresses in the project design is obtained using the model. To eliminate the aggressive medium effect on the corrosion fatigue strength of the shaft, an insulating method is used. A technique for mounting the repair structure to the shaft allowing for the outrun limitation 0.12 mm is developed.Discussion and Conclusions. Torsion shafts damaged deeply by wear and corrosion are considered. To restore their structural integrity, it is worthwhile using the following complex of techniques:— constructive (consists in the installation of optional parts that compensate for insufficient strength, and provides a reduction in stress concentration in the most loaded zones);— processing (reduces residual welding stresses due to the reasonable sequence of deformation that contributes to generating favorable residual compressive stresses);— isolation (is based on the application of anticorrosion coatings).The economic expediency of the developed repair technique is obvious. The repairing of the shaft without dismantling costs 180,000 rubles, while a new shaft costs 3.8 million rubles.

Nonlinear Delamination Analysis of Mulyilayered Functionally Graded Circular Shafts in Torsion

Nonlinear Delamination Analysis of Mulyilayered Functionally Graded Circular Shafts in Torsion

Анализ трещиностойкости торсионных валов гусеничной машины при эксплуатационных нагрузках

Анализ трещиностойкости торсионных валов гусеничной машины при эксплуатационных нагрузках

The Effect of the Shaft Diameter and Torsional Stiffness on the Whirling Speed of the Ship Propeller Shafting System

Finding the whirling speed of the shaft of the ship propeller is presented on this paper. Power generated from the engine is transmitted to the propeller directly/indirectly using gearbox. This is important to find the natural frequencies of the shafting system in order to prevent resonance. So, multi-DOF (degree of freedom) is considered on this study including engine, gearbox and propeller, flywheel and etc. connecting by the shaft. Whiling speeds of the shaft are determined at various conditions as well as the effect of the shaft torsional stiffness and shaft diameter are presented and discussed.

Innovative theory for the compliance computation in rotors

The conventional energy release rate approach to the computation of the crack compliance in rotors is critically reviewed and its shortcoming is highlighted. The state functions and the generic compliance are introduced, de ned, and veri ed. The proposed functions are de ned based on the end states' conditions and are exact. The crack compliance of the shaft in torsion is explicitly de ned as the function of the crack depth ratio and recommended as a good alternative to the classical procedure of the energy release rate method. The accuracy and eciency of the work are veri ed by concise mathematical formulation and comparison of the results of the work with the others in four examples.

Electromagnetic induced voltage signal to magnetic variation through torquing textured Fe81Ga19 alloy

The results of a study on the suitability of Fe-Ga alloys for torque sensor applications are presented. A Fe81Ga19 rod with a ⟨100⟩ preferred orientation along the length direction is prepared for the torque shaft and as the electromagnetic induction sensitive element, which is wound with three coils for signal excitation, signal pickup, and applied bias magnetic field, respectively. An apparent decrease in the induced voltage signal (peak voltage) of 3.88 mV is observed as the torque loading is 50 N m in the presence of a sine excitation signal (10 V, 1 kHz) and a bias current of 0.5 A. Meanwhile, a good repeatability and stress sensitivity are obtained, especially in the low torque range. These behaviors stem from the stress induced decrease in the magnetic permeability and the rotation of the arranged magnetic moment. Here, we use the Fe81Ga19 alloy as the shaft material; nevertheless, in practical use, the same effect can be achieved by forming a Fe-Ga layer with large magnetostriction on the surface of the torsion shaft. This work shows the prospect of Fe-Ga alloys for non-contact torque sensing, for the large magnetostriction and high sensitivity of magnetization to stress.

Improved Power Pulsation Suppression of DFIG for Wind Shear and Tower Shadow Effects

This paper analyzes and simulates wind shear and tower shadow effects in doubly-fed induction generators, which are known to induce a low-frequency oscillation. Such oscillation is called a 3p oscillation, which can cause shaft torsion load aggravation and shaft torque oscillation, it inevitably lead to electromagnetic torque and power fluctuation in the generator and further affect the whole wind power system. By analyzing a two-mass model, it can be known that a flexible drive train has a low-damping characteristic and an amplification of the input of low-frequency wind torque disturbances. Based on this point, this paper presents a new control scheme to restrain 3p oscillation is presented, which is a damping torque observation. A novel torque observer is designed to ascertain the required damping torque. A small-signal model is established for the system and used to analyze the system's static and dynamic characteristics. The effectiveness of the proposed strategy is finally verified by simulation and experimental results.

SPECIALIZED MEASURMENT SYSTEM FOR EXPERIMENTAL RESEARCH OF SUSPENSION SYSTEM LOADING CONDITIONS OF A HIGH MOBILITY TRACKED VEHICLES

Loading of cushioning systems, as a condition caused by external influences and operating conditions, for highspeed tracked vehicles is determined by the characteristics of the track profile and motion modes. The most reliable estimate of the operational parameters of loading of parts and suspension assemblies is obtained experimentally using specialized measuring equipment. Within the conducted investigations for determining of kinematic and force parameters of loading of the elements of the cushioning system of a 14-ton tracked vehicle while driving on forest ground roads, a measuring system has been developed that realizes estimation of the loading characteristics by the angular position of the suspensions relative to the vehicle body. The measuring system consists of the hardware and software subsystems and records angles of twisting of torsion shafts as a function of time, with subsequent conversion and statistical processing of obtained data into the loading characteristics of elastic elements and suspension arms. According to received sample data, the software subsystem calculates average durability of torsion shafts in order to determine the most loaded suspensions. The advantage of the study is in relative simplicity and versatility. The hardware subsystem and rigging of the sensor equipment attachment do not require making changes in the construction of the undercarriage and allows to carry out investigations on most types of tracked vehicles. The software subsystem can be adapted for studies of loading of tracked machines of different weight categories. Reliability of the test equipment, as well as stability of formation and recording of measuring signals, was evaluated in polygon tests during motion of a tracked vehicle in difficult road conditions along 350 km tracks.

Elastic-plastic fracture of functionally graded circular shafts in torsion

Analytical investigations were performed of a longitudinal crack representing a cylindrical surface in circular shafts loaded in torsion with taking into account the non-linear material behavior. Both functionally graded and multilayered shafts were analyzed. It was assumed that the material is functionally graded in radial direction. The mechanical behavior of shafts was modeled by using non-linear constitutive relations between the shear stresses and shear strains. The fracture was studied in terms of the strain energy release rate. Within the framework of small strain approach, the strain energy release rate was derived in a function of the torsion moments in the cross-sections ahead and behind the crack front. The analytical approach developed was applied to study the fracture in a clamped circular shaft. In order to verify the solution derived, the strain energy release rate was determined also by considering the shaft complimentary strain energy. The effects were evaluated of material properties, crack location and material non-linearity on the fracture behavior. The results obtained can be applied for optimization of the shafts structure with respect to the fracture performance. It was shown that the approach developed in the present paper is very useful for studying the longitudinal fracture in circular shafts in torsion with considering the material non-linearity.

Shaft Torque Limiting Control Using Shaft Torque Compensator for Two-Inertia Elastic System With Backlash

This paper aims to present a solution for torsional vibration suppression and shaft torque limitation simultaneously in servo system with backlash. The existence of backlash, which would make conventional notch filter invalid, will aggravate the mechanical vibration and bring the risk of unsafety to the system. In order to solve that problem, a novel shaft torque compensator is proposed, which would make the system similar to a rigid system with one inertia. What is more, this compensator can limit shaft torque as expected, making the system relatively safe under any situation with different load inertias and torques. The limiting control is based on the adaptive online identification of load inertia in order to improve robustness of the system and ensure not only the accuracy, but also the arbitrariness of shaft torque limit. Simulation and experimental results are presented to illustrate the favorable behavior of the drive with the robust shaft torque compensator.

복합하중을 받는 복합소재 중공 토크바 설계

복합하중을 받는 복합소재 중공 토크바 설계

Increase of durability for torsion shafts and long details by surface plastic deformation

Device for hardening of external cylindrical surfaces of long details by surface plastic deformation is proposed. Device provides an impact interaction of surface of the detail with massive hardener that eccentrically mounted on it. Spherical deformable bodies are set on working surface of the hardener. Manageable depth for hardening of constructional steel details is 0,10 ÷ 0,20 mm

Reliability design of the hinge kit system subjected to repetitive loading in a commercial refrigerator

A newly designed hinge kit system (HKS) of a commercial refrigerator was subjected to a robust reliability methodology during the design phase of the system. This methodology included setting the overall parametric accelerated life test (ALT) plan of product and identifying failure mechanisms and modes in field. The ALT included a sample size equation to improve several of the HKS design parameters. Reliability of the new HKS was targeted to be 10 years over B1. Failure sites in the HKS were identified through returned products from the field. The first ALT confirmed a failure that occurred at the housing of HKS. The missing design parameters of HKS housing for the refrigerator were that it had no support ribs in the original design. The supporting structure of HKS in the refrigerator was modified based on the action plan. Cracks were identified in a second ALT that was generated in the torsional shaft. Due to it having squared off corners, the HKS torsional shaft did not have not enough strength to withstand repetitive stresses. The shaft was modified as a consequence of the ALTs. The reliability of redesigned HKS is now guaranteed as B1 10 years. The design methods - load analysis and three ALTs were very effective in identifying the missing design parameters during the design phase. The robust design method presented in this paper might be applicable to the other mechanical systems.

FBG光ファイバセンシングによる回転軸表面のねじりひずみ分布計測

Structural health monitoring has been used to confirm the durability evaluation and safety of a structure in which long-term use is required. Because the transmission loss of the optical fiber sensor is extremely small, it can measure the present status of structures from far away. Generally the FBG (Fiber Bragg Grating) optical sensing systems are often used to get reliable indices from structures. The shipping industry recently, there has been a growing interest in fuel efficiency improvements and energy regulation in international shipping. Therefore, during sailing, to measure the exact power of the main shaft of the ship has become important. We proposed the monitoring system using space optical transmitting of the FBG optical fiber to get information from a rotational shaft. And we evaluated the performance of the space optical transmission of the FBG optical fiber sensing system for rotational shaft in the previous study. Consequently, we reported that it can be effectively measured and space optical transmission metric is effective for performance prediction. In this paper, the strain and the temperature on the rotating torsion shaft, is measured by the FBG optical fiber sensor and the space optical transmission. We confirm reliability of the information that is retrieved from the rotating shaft subjected to torsion in the experiment. The conditions for reliable data from the rotating shaft under loading is obtained on the basis of the experimental results of the proposed systems.

Wind turbine drive train dynamic characterization using vibration and torque signals

Dynamic analysis of wind turbine drive train subjected to stochastic aerodynamic loads is carried out in the present study. The longitudinal wind speed at the turbine site normally consists of a mean value superimposed with ramp, gust and turbulence components. In the present study, the aerodynamic torque is obtained by considering wind speed parameters of a typical wind turbine site. The dynamic model accounts for time varying gear mesh stiffness, bearing elasticity and torsional shaft stiffness. The dynamic analysis is done with stochastic aerodynamic loads and the vibration responses are obtained in time and frequency domains. It is observed that the entire spectral content of the vibration signals is confined to low frequency region, whereas higher frequencies are hidden. In order to capture the hidden frequency information from vibration signals, the wavelet decomposition technique is used. The dynamic analysis using torque signals is also discussed. The present study shows that, from the internal resistive torque all the characteristic frequencies can be clearly observed.

Vibration Suppression With Shaft Torque Limitation Using Explicit MPC-PI Switching Control in Elastic Drive Systems

In this paper, the application of model predictive control (MPC) for torsional vibration suppression and shaft torque limitation control in the elastic drive system is demonstrated. Standard MPC is converted to fast explicit MPC (EMPC) to solve its difficult online implementation issues. Constraint condition of shaft torque limitation control is first proposed through theoretical derivation, implying that the responses of shaft torque vary with the changed critical value of shaft torque, but the limitation function can still be available. Eventually, the EMPC-PI switching control is used for the application of shaft torque limitation control into the typical drive successfully, which can significantly reduce the amount of data storage, closer to practical industrial applications. Meanwhile, the advantage of eliminating the steady-state error provided from the PI controller can further enhance robustness of the system, compared with the pure EMPC controller. The switching criterion is based on the speed hysteresis value, which can be properly adjusted under different circumstances. Simulation and experimental results of speed step responses verify the EMPC-PI switching controller as a more effective approach compared with the PI controller designed by pole-placement method.

The Mechanism of Hardening and Internal Stress Stabilization in the Process of Laser Treatment

We propose a mathematical model of the temperature-field formation inside and outside the laser-irradiated region and study its dependence on the laser-pulse treatment conditions. We describe the process of summation of the surface temperatures due to close laser pulses and provide recommendations on choosing an optimum laser regime for treatment of moderately hard surfaces, such as torsion shafts.

Analysis of Action Viscous Torsional Vibration Damper of the Crankshaft Based on Transverse Vibration the Engine Block

The article presents an example of research results of the mechanical vibrations of the internal combustion engine with a viscous torsional vibration damper of the crankshaft for different values of the viscosity of silicone oil. A comparison of the crankshaft torsional vibration and the transverse vibration motor body was made. There was proposed the use of the information contained in the transverse vibration signals in order to determine the changes in the technical condition of the viscous damper (changes in viscosity of silicone oil fillingthe damper). Accepting the argument which assumes that there exists the coupling vibration and torsional shaft bent in transverse vibration signals, there should appear symptoms associated with changes in the torsional vibrations. In order to prove this thesis there was conducted active research experiment. Measurements of transients during engine acceleration were made. There was presented the example of the results of measurements of the crankshaft torsional vibrationand the transverse vibration of the motor body.