Shaft Weight Research Articles

Opportunities to Enhance sCO2 Power Cycle Turbomachinery with Bearingless Motor/Generators

Thermal power cycles using sCO2 as a working fluid place extreme demands on their turbomachinery components and their electric motors/generators. In this paper, new system topologies for sCO2 turbomachinery are proposed which take advantage of “bearingless” electric machine technology to improve performance. Bearingless motors/generators are a new type of electric machine which integrate the functionality of active magnetic bearings into the existing hardware of an electric motor/generator. The existing electromagnetic surfaces and materials are reused to enable controllable production of radial forces on the machine shaft. This is envisioned to improve hermetic direct-drive turbomachinery systems by either augmenting existing bearings (i.e., bearing assist) or replacing existing bearings (i.e., bearing removal). The state-of-the-art technologies for several bearing types (gas foil bearings, externally pressurized porous (EPP) gas bearings, and active magnetic bearings) and electric machines are reviewed to motivate the introduction of bearingless technology. Two system designs using bearingless machines are proposed and compared against existing commercial solutions in terms of maximum shaft weight, number of passthroughs into the hermetic environment, cost, and complexity. A case-study bearingless motor/generator is assessed via simulations and a hardware prototype to investigate practical considerations for using bearingless technology in sCO2 turbomachinery. The proposed bearingless solutions have potential to enable a new generation of sCO2 turbomachinery with improved reliability, reduced complexity, and lower cost. This paper shows that by transforming the motor/generator already present in turbomachinery into a bearingless motor/generator, the technical challenges involved with sCO2 can be overcome without adding significant cost.

A π-Theorem-Based Advanced Scaling Methodology for Similarity Assessment of Marine Shafting Systems

This paper introduces a rigorous and comprehensive approach to the assessment of marine shafting systems through the utilization of an advanced π-Theorem-based scaling methodology. Integrating journal-bearing similarity assessment and shaft-line scaling methodology with advanced dimensional analysis, the study aims to provide a methodology foundation for systematic replication and analysis of marine shafting systems through scaled models. The proposed scaling methodology ensures geometric and mechanical similarity in terms of shaft-line deflection, considering key scaling parameters such as shaft length, diameter, weight, loads, rotational speed, material properties, bearing locations, and offsets. The advanced dimensional analysis computes specific non-dimensional ratios to guarantee a close resemblance between a real-size system and a scaled lab model. The methodology is analytically derived and validated with numerical simulations for a case study, conducting comparative analysis, evaluating discrepancies, and utilizing the integrated framework for experimentation.

Strength-to-Weight Optimization of Driver Shafts: A Comparative Analysis of Material Selection, Manufacturing Methods, Generative Design, and Topology Optimization using Fusion 360

This study presents a comprehensive comparative analysis of strategies for optimizing the strength-to-weight ratio of driver shafts in automobile applications. The research focuses on four key areas: material selection, manufacturing methods, generative design, and topology optimization. Firstly, a range of materials commonly used in driver shaft manufacturing is evaluated, considering factors such as strength, weight, durability.. Various manufacturing methods, including traditional techniques and advanced processes like additive manufacturing, are assessed for their impact on shaft performance. The study also delves into the application of generative design and topology optimization techniques. Generative design algorithms are employed to explore innovative shaft geometries that enhance structural integrity while minimizing weight. Topology optimization algorithms are utilized to optimize material distribution within the shaft, further improving strength-to-weight characteristics. The findings highlight the potential benefits of integrating advanced design methodologies with appropriate material selection and manufacturing processes. This research contributes valuable insights for optimizing driver shafts, enhancing automobile performance, and achieving efficient utilization of materials in automotive engineering. Key Words: Driver Shaft design, Strength and weight optimization, Generative Design, Topology Optimization, Material and manufacturing Consideration.

A CFRP/steel hybrid rotating shaft for a high-speed motorized spindle

Most key industry machines have a rotating structure for power transmission, which plays a crucial role in diverse engineering practices. In machine tools, a spindle is the heart of machining centers, and the quality of the spindle has a critical influence on overall machining errors across different manufacturing processes. Especially, axial growth due to thermal displacement of the shaft directly adds depth accuracy error of the tool. While additional compensation control techniques have been developed to cover such errors of spindles in practice, fewer efforts have been made to improve the actual amount of error in the spindle. This study introduces a new carbon fiber-reinforced composite (CFRP) fabricated hybrid design in a rotating shaft for a high-speed motorized spindle. With superior material characteristics of CFRP, it aimed to improve thermal displacement as well as light-weighting of the shaft. The developed spindle with composite shaft was tested in comparison with an equivalent spindle with a conventional single material shaft, and it achieved 18 % shaft weight reduction and 22 % improvement in shaft thermal growth. Furthermore, it was successfully tested in vertical face grinding of silicon carbide (SiC), providing accuracies over 99 %. Machining precision achieved conspicuous difference with 45.4 % enhancement at 3000 rpm and 27.3 % at 5000 rpm grinding. The significance of this study lies in that it suggests the first generalized method of adopting carbon fiber composite in rotating systems, including high-speed motorized spindles, which also proves its feasibility in actual machining.

The effects of different iron shaft weights on golf swing performance.

This study examined the effects of three 7-iron shaft weights on golf swing performance among golfers of varying skill levels. The study included 10 low-handicap (LH; 4.3 ± 2.4) and 10 high-handicap (HH; 29.1 ± 5.4) right-handed golfers as participants. The participants were randomly assigned 7-iron clubs with shaft weights categorized as light (77g), medium (98g), or heavy (114g), and they performed test shots. Kinematic data were captured using a motion analysis system with nine infra-red high speed cameras; a force platform connected to this system was used to record weight transfer patterns. Performance variables were assessed using a FlightScope launch monitor. A two-way mixed-design analysis of variance was used to determine the significance of the performance differences among both participant groups and golf shaft weights. The results indicated that during the backswing, the LH group exhibited significantly greater maximum rightward upper torso rotation, maximum X-factor, and maximum right wrist hinge rotation than did the HH group. During the downswing, the LH group exhibited significantly greater maximum upper torso angular velocity and maximum right wrist angular velocity than did the HH group. Moreover, the LH group produced significantly higher ball speeds, longer shot distances, and lower launch angles than did the HH group. The shaft weight neither greatly altered the golf swing nor displaced the center of gravity of the golfers. The lighter shafts were observed to facilitate faster clubhead speeds and initial ball velocities, thereby resulting in longer shot distances, especially among LH golfers. Although significant differences in swing mechanics and performance exist between HH and LH golfers, lighter shafts can contribute to increased shot distances for all golfers.

Influence of Axle Weight and Frequency on the Tribological Properties of Laser-Repaired 316L Stainless Steel Coatings in Railway Wheel Tread Braking

The impact of the complex braking environment on the service performance of the repair fusion cladding was studied, which is of great significance to improve the ability of the train wheel track system to resist the extremely harsh environment. In this paper, a 316L stainless steel coating was prepared using laser fusion cladding repair technology for the local damage location of the train wheel tread. The MS-HT1000 high-temperature wear tester was used for the experiment. Then, the influence of different braking conditions on the friction and wear performance of the repaired specimens at room temperature and high temperature was analyzed. The results showed that the microstructure of the laser-repaired 316L stainless steel coating was dendritic and eutectic, and its physical phase was mainly composed of austenite, Fe-Cr, and carbides. The wear rate increases with the rise in the shaft weight load, indicating that the higher the contact load, the more severe the wear. In contrast, the influence of the friction coefficient in a room temperature environment is less variable. With an increase in the braking frequency, the wear of the specimen firstly rises and then decreases, and when the frequency is 1 Hz, the value of the wear rate at room temperature is the largest, and the wear surface appears as more peeling layers, and a large amount of wear debris is randomly distributed, which manifests as the wear mechanism being characterized by abrasive wear and adhesive wear. Therefore, different factors affect the wear level of the material differently, with the axle weight load having the greatest influence. The relevant results help to provide corresponding theoretical references for the optimization of parameters under the braking condition of the wheel tread, which ensures the normal operation of the braking system when driving.

Design and Analysis of Propeller Shaft for Automobile

Almost all automobiles have transmission shafts. The propeller shaft have some loss due to weight. The weight reduction of the drive shaft can have a certain role in general weight reduction of the vehicle and is a highly desirable goal. Exploring composite materials in order to obtain reduction of weight without significant decrease in vehicle quality and reliability. To start the vehicle the most of the power consumed in driving transmission system, if we able to reduce the weight of the propeller shaft that surplus available power can be used to propel the vehicle.

Generalized Breathing Functions for Stiffness Model of Transversely Cracked Hollow Shaft

The exact breathing mechanism of the transverse crack in the hollow shaft that appears due to the shaft weight is important to analyze correctly the dynamic behavior of the rotor system. We discuss a breathing phenomenon which appears only in the hollow shaft rotation and determine the exact time-varying area moments of inertia for the cracked element cross-section. Considering the variation behavior of the area moments of inertia, generalized breathing functions are suggested to formulate the finite-element stiffness matrix of the crack element. The harmonic balance method (HBM) is employed to solve the finite-element model of the rotor-bearing-disk system. We study the influence of ratio of the internal and external diameter of shaft, dimensionless crack depth, location of crack and angle between the crack and imbalance directions. Some significant behaviors of the system are compared with some previously published results, and they can be contributed to detecting the crack in hollow shaft early. Comparison shows the generalized breathing functions are accurate to model the stiffness variation of shaft due to the crack.

“Fatigue Analysis Of Epoxy Composite Material Reinforcement On Propeller Shaft”

Propeller shaft, also known as propeller shaft is the most important component to any power transmission application; automotive propeller Shaft is one of this. A propeller shaft is a mechanical part that transmits the generated torque by a vehicle's engine into motive force which is usable to propel the vehicle. Substituting composite structures for metallic which is structures has many advantages because of higher specific stiffness and strength of composite materials. This work deals with the conventional replacement of steel propeller shafts with fiberglass epoxy composite propeller shaft for an automotive application. The parameters of design were optimized with the objective of minimizing the weight of a propeller shaft. The design optimization also improves the performance of propeller shaft. Present work deals with FEA analysis of composite shaft with different degree of orientation of glass fibers. It includes the modeling of shaft in CATIA. The meshing and boundary condition application will be carried using Hypermesh, Fatigue analysis of composite shaft will be carried out using ANSYS.

Design and comparison of the strength of propeller shaft for truck made of AA2024, AA7068, and Ti-6Al-4V using ANSYS

Now a day in the automobile field, immense interest in the weight-free material, for instance, fabric material developed combination of different macromolecules, is by all accounts a promising answer for this emerging interest. These materials stand out because of the need in the area of vehicles, aircraft, etc. The general goal of this work is to break down an alternate material propeller shaft to increase torque transmission. Subbing alloy material constructions to ordinary designs have numerous benefits on account of higher explicit hardness and strength of composite materials. This work manages the substitution of ordinary steel propeller shafts with an Aluminum alloy (2024 and 7068), Titanium alloy (Ti-6Al-4V) composite propeller shaft for automotive applications. Normally we use SM45C steel for propeller shafts. The intention is that decrease the weight of the propeller shaft. In this research, we estimate the deflection, tension, and other tests taken with weight by utilizing Finite element analysis (ANSYS). The design is done with CATIA V5. Moreover, an examination was done for the load utilizing Finite Element Analysis (FEA) Further comparing both steel and composite propeller shafts.

Finite element analysis of vehicle composite propeller shaft

When designing a new automobile, weight reduction has become a common practice. In order to comply with stricter environmental regulations, it is necessary to reduce weight. If you'll pardon my technical jargon, manufacturers have been working hard to reduce the overall weight of their vehicles since the prototyping stage. A passenger car's propeller shaft was analyzed and optimized for weight reduction in this study. The shaft's natural frequency and durability were studied using finite element analysis and testing. Based on the structural analysis, it is found that propeller shaft weight reduced by 6.1%.

Optimal Design of Transmission Shafts Using a Vortex Search Algorithm

This paper analyzes the problem of optimally sizing a transmission shaft via the vortex search algorithm (VSA) optimizer. The objective function was to minimize the shaft weight through an adequate selection of the diameters of each section of the device, and the constraints were the physical conditions that should be met to design safe, fatigue-proof shafts. The solution and the mathematical model were validated using Autodesk Inventor. In addition, the performance of the VSA was compared to that of the continuous genetic algorithm . The numerical results show that the programmed model has the physical and methodological characteristics needed to produce a better output than conventional design techniques. Therefore, this model can be a powerful tool to solve nonlinear non-convex optimization problems such as the case investigated here.

Periodic, Quasi-Periodic, and Chaotic Motions to Diagnose a Crack on a Horizontally Supported Nonlinear Rotor System

This work aims to diagnose the crack size of a nonlinear rotating shaft system based on the qualitative change of the system oscillatory characteristics. The considered system is modeled as a two-degree-of-freedom horizontally supported nonlinear Jeffcott rotor system. The influence of the crack size on the system whirling motion for the primary, superharmonic, and subharmonic resonance cases are investigated utilizing the bifurcation diagram, Poincaré map, frequency spectrum, and whirling orbit. The obtained numerical results revealed that the cracked system whirling motion is subjected to a continuous qualitative change as the crack size increases for the superharmonic resonance case, where the system can exhibit period-1, period-2, quasi-periodic, period-3, period-doubling, chaotic, and period-2 motions, sequentially. In addition, an asymmetry is observed in the system whirling orbit due to both the shaft weight and shaft crack. Moreover, it is found that the disk eccentricity does not affect the nature of these motions. Accordingly, we illustrated a simple method to diagnose the existence of such a crack and to quantify its size via monitoring the system lateral vibrations at the superharmonic resonance. Finally, all the obtained numerical results are concluded and a comparison with already published work is included.

Transmission error investigation of gearbox using rigid-flexible coupling dynamic model: Theoretical analysis and experiments

The transmission error (TE) is one of the most important excitations of gearbox vibration. In previous studies, simplified models composed of meshing gears alone were built to analyze the TE. However, the flexibility of other system components was ignored. In this study, a system-level TE investigation of gearbox is carried out by proposing a rigid-flexible coupling dynamic model. In this model, the meshing pair, flexible shaft, and bearing are established by a lumped mass element, beam element, and spring element, respectively. Housing flexibility is introduced into the analysis through model condensation, and a modal test is launched to verify its effectiveness. Moreover, a TE test rig is set up to compare the theoretical and experimental results. These results show that the TE increases with increasing load. Furthermore, the TE decreases when the housing flexibility is considered, especially when the gearbox is running at higher speed and when the housing is a thin-walled structure. Appropriately decreasing the stiffness of the housing can decrease the TE. Additionally, increasing the inner radius of hollow shaft simultaneously reduces the shaft weight and decreases the system TE.

Three-objective optimization of aircraft secondary power system rotor dynamics

Secondary power system based on gas turbine engine is usually used for starting the aircraft main engine at ground and finds similar application in air during the emergency. The secondary power system comprises of an auxiliary power unit (APU) and an air starter. APU provides stand-alone power to the main engine subsystems and air to the air starter for starting main engine. The main rotor system of APU is to be designed for safe operation during the ground critical speed crossing and maneuver loading. The weight of such a rotor system is an important design criterion. In the current work, multi-objective optimization using hybrid genetic algorithm (HGA) is employed for simultaneously minimizing the response at critical speed, the response during maneuvering, and shaft weight of the APU rotor system used in secondary power system of an aircraft. The shaft considered is a stepped one and is modeled using Rayleigh beam elements with three disks. Effects due to gyroscopic effect are also included in the analysis. A Pareto front is generated, and subsequently, an optimal solution is selected for the problem. The comparison with typical two-objective optimization result, having response at critical speed and shaft weight as objectives and response during maneuvering as constraint, has shown that the novel three-objective optimization has provided the designer with improved design choices for the selection of final compromise solution.

Study of an inducer and axial vortex stage

Increasing the intake capacity and reducing vibration loads of high-speed pumps is an important task in the development of power systems in the aerospace industry, as well as in the application of such pumps in the energy and oil production sectors. With an improvement in cavitation qualities, pumps can operate at a higher shaft speed, and at a given shaft speed, with lower net positive suction head, that is, at reduced inlet pressure. With increasing shaft speed, the dimensions and weight of the pumps decrease. To increase the cavitation qualities of the pumps, an axial vortex stage (AVS), which is an object of comparison with the inducer, is considered as an upstream device. It is necessary to study the fact of pressure pulsations decrease when using the AVS. The results obtained with computational fluid dynamics to analyze pressure pulsations in the inducer and in the AVS are used in this article.

Weight efficiency analysis of a ship carbon shaft manufactured by winding with various winding angles in layers

The task of the optimal winding parameters selection for the ship composite intermediate shaft has been formulated and the solution algorithm has been considered. A method for the shaft mechanical characteristics estimation on the base of the layer-by-layer method has been proposed. The shaft weight efficiency analysis for the various winding angles in the winding program has been carried out.

Analysis of Automobile Shaft for Optimizing Weight by Using Fem

Composites have been increasingly used in many engineering fields. Polymer composites are now widely used to build automotive components due to their exceptional rigidity and strength properties. Composite shafts for automotive applications are among the most recent research areas. A weight reduction can be achieved mainly with the introduction of a better material. The conventional system uses a metal shaft and has inherent limitations such as weight, corrosion, elasticity, vibration, storage and manufacturing problems increase with increasing shaft diameter. Advanced composites offer the opportunity to improve the transmission shaft by reducing weight, bearing load, misalignment and life cycle costs through the use of strategic materials, increasing the properties of resistance to fatigue, flexibility and vibration damping. The objective is the design and analysis of composite hollow shafts made of low density carbon fiber reinforced plastic (CFRP) for motor vehicles. And To investigate the vibrational effect of propeller shaft at different mode condition using FEA by ANSYS 18.2. In this result are the total weight of carbon fiber shaft is reduce. The total weight of the carbon fiber shaft is 2.6 kg is less then to previous material. And the previous study material of weight is 3.2kg.

Design and development of plantain fibre extraction machine

The traditional retting technique of extracting plantain fibres is faced with various constraints such as longer extraction time and poor fibre production rate. This study is targeted at overcoming the limitations associated with traditional methods of extracting plantain fibres through the development of electrically powered machine capable of extracting plantain fibres. The method employed involves the selection of appropriate materials, design, fabrication and assembly of the various components of the machine parts. From the analysis a 2 horsepower electric motor is required to drive the machine. The length of flat-belt required to drive the pulley was 1.47 m at an angle of lap on the smaller pulley of 2.87 rad. A resultant load of 174.87 N act on 11.6 mm diameter shaft with maximum bending moment of 10.33 Nm. The total weight of shaft, pulping drum and bearing on frame was 67.51 N. Also, a force of 150 N, 200 N and 250 N could pulp a thickness of plantain ribs of approximately, 6 mm, 6.5 mm and 7 mm, respectively. The test result showed that the machine could extract a sliced pseudo stem thickness between 4.0 mm and 10 mm at 27 and 42 seconds, respectively. It is expected that the plantain fibre extraction machine fabricated would save plantain fibre production time.Keywords: Plantain fibres, Pseudo stem, extraction machine, retting technique

Reserves for improving the design of shafts

Shafts are used in almost all machines and mechanisms. Unlike other parts, the destruction of the shafts is very rare. As it was supposed earlier, it is connected with high level of perfection of a technique of their calculation and design. The article analyzes the features of the three traditional methods of shaft design and shows that the shafts are not destroyed for the reason that traditional methods lead to a significant, up to 27 and more times, overestimation of the diameters of all the characteristic areas in comparison with the size sufficient in terms of the strength of the shaft. The area of its cross-section and, accordingly, the mass can be overestimated by more than 750 times. Such unjustified overestimation of the shaft diameter and weight cannot be considered as an indicator of the perfection of the shaft design and calculation methods, and, on the other hand, is an important reserve for the improvement of their designs. This is particularly true for those mechanisms that are subject to increased requirements in terms of minimum size and weight.