Arc Springs Research Articles

Review on Performance of Dual Mass Flywheel over Conventional Flywheel

The Dual Mass Flywheel is used for dampening the oscillations created at the time of working in automotive power transmission system.Dual mass flywheel is a multi-clutch device. The torsional frequency is defined as the rate at which the torsional vibration produced. When the torsional frequency of the crankshaft is equal to the transaxles torsional frequency an effect known as the torsional resonance occurs. When the operating speed of the engine is minimum, vibration occurs due to the torsional resonance and this can be avoided using dual mass flywheel.We explained detailed initial model in the paper. In this mainly having the two arc springs and two masses in the DMF and their nature. By experiment the Dual Mass Flywheel model is compared to convention flywheel. Finally the observation of the engine torque using the DMF is taken. The DMF is manufactured and done experiment or testing to see the results. And then results which came are compare with the conventional flywheel.

Structural design optimization of the arc spring and dual-mass flywheel integrated with different optimization methods

Abstract This paper is about the structural design optimization of the torsional arc spring and the dual-mass flywheel (DMF) using three different population-based optimization techniques: Particle swarm optimization (PSO), differential evolution (DE), and genetic algorithm (GA). For this purpose, the equations of the motions of the vehicle powertrain are derived and implemented into the dynamic analysis to minimize the vehicle torsional vibrations. The parameters and initial angles of the arc spring are optimized by considering the objective function that is the sum of the maximum acceleration amplitudes of the crankshaft vibrations. The results demonstrated that the proposed design procedure is able to provide a proper arc spring and DMF inertias to reduce the torsional vibration significantly. Moreover, it is indicated that the DE optimization techniques provide best performances than others. Finally, it is also shown that the natural frequencies can be reduced by the DMF and the optimization results are under the idling critical speed of the engine. The obtained results of this paper are of utmost importance for the arc spring manufacturer about the design process considering both DMF and spring parameters simultaneously to minimize torsional vibration of the vehicle powertrain.

Numerical Evaluation and High-Speed Rotating Test on Circular Arc Spring Dampers for Centrifugal Compressors

Abstract A circular arc spring damper (CASD) is a recently proposed fluid-film damper that has two or more arc-shaped centering springs and dual radial clearances formed by wire electric discharge machining (WEDM). CASD requires less space and weight than a conventional cage-centered squeeze-film damper (SFD). It provides linear stiffness and stable damping force in rotor-bearing systems to attenuate vibration due to imbalance or to improve rotordynamic stability. The authors have been investigated the dynamic characteristics of CASD in component-level experiments. However, their performance and applicability to real machines have not been confirmed in system-level experiments. Additionally, a theoretical means of evaluation for CASD should be established to predict its dynamic coefficients and to understand the mechanism of dynamic force generation. In the first part of this study, a numerical evaluation method using two-way fluid–structure interaction (FSI) analysis and its theoretical background is presented. Transient structural analysis and fluid-film flow analysis with a simple homogeneous cavitation model are coupled in the commercial multiphysics platform ansys. The accuracy of the method was validated by comparing the damping and added-mass coefficients with results from previous experiments. Furthermore, several aspects of the force generation mechanism and the difference from conventional SFD were studied numerically. The second part of the study addresses the application of CASD in a multistage centrifugal compressor. A combined 4-in. diameter, five-pad tilting pad journal bearing (TPJB) with four-arc type CASD was newly designed and manufactured. To prove the applicability of the developed damper bearing, a series of rotating tests were conducted at a high-speed balancing facility with a full-scale dummy rotor with a critical speed ratio (CSR) of approximately 3.1. The measured unbalance response showed a much lower amplification factor (AF) than that of the conventional TPJB without the damper, which infers a significant improvement in the stability. The measured responses agreed with the rotordynamic analysis, which uses the dynamic coefficients of CASD derived from the proposed numerical evaluation method.

Numerical Studies on the Stiffness of Arc Elliptical Cross-section Helical Spring Subjected to Circumference Force

Due to its excellent properties, elliptical cross-section helical spring has been widely used in automobile industry, such as valve spring, arc spring used in Dual Mass Flywheel and so on. Existing stiffness formulae of helical spring remain to be tested, and stiffness property of elliptical cross-section arc spring has been little studied. Hence, study on the stiffness of elliptical cross-section helical spring is significant in the development of elliptical cross-section helical spring. This paper proposes a method to study the stiffness property of elliptical cross-section helical spring that the experiment design method is adopted with finite element analysis. Firstly, the finite element analysis method was used to verify the cylindrical (circular cross-section and elliptical cross-section) springs. Then, the regression formula was designed and derived compared with the reference springs’ stiffness formulae by experimental design. Last, regression formula was verified with existing experiment data. The novelty in this paper is that simulation technology of arc spring was investigated and a stiffness regression equation of arc elliptical cross-section spring was obtained using orthogonal regression design, with significance in wide use of the arc elliptical cross-section helical spring promotion.

Experimental Evaluation of Dynamic Characteristics of Circular Arc Spring Dampers for Rotating Machinery

Abstract This study presents an experimental evaluation of the dynamic characteristics of the circular arc spring damper (CASD), which attenuates the vibration of rotating machinery. The CASD is a novel type of fluid film damper that has two or more arc-shaped beams and dual slits (radial clearances) formed by wire electric discharge machining (WEDM). A major advantage of CASDs over conventional squeeze film dampers (SFDs) with squirrel-cage springs is their compactness and low weight. The concept of CASDs was originally proposed by Kanki et al. (2005). However, the basic characteristics of this type of damper, including the influence of the geometries, added mass coefficients, and cross-coupled terms of dynamic coefficients have not been investigated. To clarify these characteristics, a series of excitation tests was conducted on three types of CASDs to identify their dynamic coefficients. The features of the newly developed test rig and experimental results are presented in this study. Tested dampers have the same outer diameter (160 mm) and damper width (44 mm) but different arc patterns (2-arc or 4-arc) and radial clearances (about 0.3 or 1.2 mm). All dampers were tested in both open-end and end-sealed configuration. The influence of the end-seal clearances (about 0.1–0.4 mm) was also examined. The following results were obtained: (1) 4-arc type CASDs have greater damping than that of 2-arc types; (2) CASDs have a considerable amount of added mass coefficients, especially in the end-sealed condition; (3) smaller end-seal clearances make the damping and added-mass coefficients significantly larger; (4) A large level of damping can be produced with dashpot configuration (large radial clearances and small end-seal clearances), though the added-mass effect becomes more prominent; (5) cross-coupled terms are very small in centered/small amplitude motion. These new findings can be utilized for the design and application of CASDs to real rotating machineries.

Characterization of the torsional vibration behavior of circular and rectangular cross-sectional arc springs: Theory and experiments

Abstract This paper is about the theoretical and experimental characterizations of the torsional vibration behavior of circular and rectangular cross-sectional arc springs. Firstly, the dynamic behaviors of arc springs with different cross-sectional wire profiles designed for a dual mass flywheel are modeled by mathematical formulations. After that, experimental tests are performed to verify these models and it is observed that the stiffness characterizations are in good agreement with experimental results. Lastly, the masses of two different arc springs are compared by regarding the same vibration stiffness criteria and it is demonstrated that the rectangular wire provides an arc spring with a 9.44 vol.-% lighter structure. Thus, the outcomes of this paper can be good references for the manufacturer about the numerical and experimental characterization of dual mass flywheel springs, especially for rectangular wire arc springs.

Discretization Method for Arc Spring in Torsional Damper

Discretization Method for Arc Spring in Torsional Damper

Modeling and Experimental Study on Dynamic Characteristics of Dual‐Mass Flywheel Torsional Damper

Theoretical modeling and experimental research are carried out on the dynamic torsional characteristics of a dual‐mass flywheel (DMF) in this paper. Firstly, the structure and working principle of the DMF are analyzed. Secondly, the arc spring is analyzed by the discrete element method. For the different frictional torques in the working process, the linear fitting and equivalent energy methods are used to model the frictional torque under the dynamic condition of the arc spring. The fractional derivative model is used to model the viscous damping of DMF. Then, the parameter identification and model verification are carried out on the model, and the model error is analyzed. Finally, an experimental study on the dynamic torsional characteristics of DMF is carried out. The results demonstrate that the torsional stiffness of the DMF varies with the excitation amplitude and frequency. This modeling and test method can be used for structural design and performance prediction analysis of DMF.

Analysis of Effect of Inlet Swirl In Four Stroke Single Cylinder Diesel Engine With Different Inlet Valve Geometries Using CFD

Flow patterns are essential to ensure that the engine can produce high performance with the presence of swirl and tumble effect inside the engine cylinder. This paper provides the simulation of air is simulated in the software to predict the flow pattern. The flow pattern is simulated by using the steady state pressure based solver. The domain used for the simulations predicated on the particular engine parameters. Mistreatment the CFD problem solver ANSYS FLUENT, the CFD simulation is earned for four totally different geometries of the valve. The geometries consist of Horizontal, Vertical, curve and arc springs. In this simulation, only the intake strokes are simulated. From this results show that the velocity of the air flow is high during the sweeps the intake stroke takes place. This situation is produced more swirls and tumble effect during the compression, hence enhancing the combustion rate in a whole region of the clearance volume of the engine cylinder. This will initiate to the production of tumble and swirl in the engine cylinder.

Static Torsional Stiffness Computation of Circumferential Arc Spring Dual Mass Flywheel

The iterative formulas of spring forces for Circumferential Arc Spring Dual Mass Flywheel (DMF-CS) were derived by discrete method, involving friction forces. The computation program was designed, and the curves illustrating transmitted torques over deformation angles of the outer and inner arc springs were plotted, which showed linear torque behavior. Thus two stages of torsional stiffness of DMF-CS were figured out to be 465.9923Nm/rad and 631.7980Nm/rad. The two stages of torsional stiffness without friction forces were calculated by this method, which were 434.6408Nm/rad and 591.3652Nm/rad. The experiment of static torque characteristic of DMF-CS was completed, obtaining the experimental torsional stiffness, which were 455.9923Nm/rad and 620.9412Nm/rad. Comparing the above values of torsional stiffness, the values with friction forces show more precise than ones without friction forces, and the values without friction forces are smallest. The results show that the friction forces contribute to the torsional stiffness of DMF-CS.

A Study of a Dynamic Vibration Absorber Using Circular Arc Springs and Magnetic Damping

A new type of two-dimensional dynamic vibration absorber which has a simple construction and low height has developed. The dynamic absorber is composed of a mass, semicircular arc springs, rare-earth magnets and free bears, and is able to move in every horizontal direction. The dynamic absorber is suitable for suppressing the vibration of small structures, such as three-story wooden houses, due to an earthquake, a wind or a ground motion. The modal mass and stiffness were calculated, and the optimum condition of the dynamic absorber was calculated using the fixed points theory and the area under the acceleration curve. The trial dynamic absorber was made and its resisting force characteristics were discussed experimentally and theoretically. The trial dynamic absorber was attached to the third story of a 3-story building model, and the frequency and seismic responses of the building model were measured using a permanent magnet type vibration table. The experimental results were compared with the calculated results, and the effects of vibration suppression of the dynamic absorber and the propriety of the calculations were confirmed.

Isolation Table Using Horizontal Circular Arc Springs and Magnetic Damping

In this paper, a two-dimensional isolation table using circular arc springs and a magnetic damper, which has a simple construction, low height and the capability of vibration isolation in every horizontal direction, is proposed. The isolation table is composed of eight circular arc springs, twelve free bears, a magnetic damper, a table board and a base board. It has approximately the same stiffness and damping coefficient in every direction in the horizontal plane. The response acceleration spectra of the isolation table for two kinds of actual seismic acceleration waves are calculated to confirm the effects of isolation on the seismic responses of the table. A trial isolation table was made and its resisting force characteristics were investigated theoretically and experimentally. The seismic responses and the frequency responses of the table which was installed with a mass or a tall furniture-type model were measured using an electrohydraulic-type vibration machine. The experimental results were compared with the calculated results, and the effects of vibration suppression of the table were confirmed.

3406 三次元防振・免震テーブルの開発研究(OS16 製造現場と設計・システムII)

In this paper, a three-dimensional vibration isolation table using semicircular arc springs, which is a seismic isolation table for horizontal directions and a vibration isolation table for vertical direction, and a vertical seismic isolation table using a rack and pinions were developed. The trial vibration isolation tables were made and their effects of vibration isolation were discussed experimentally and numerically.

A Study of an Isolation Table Using Horizontal Circular Arc Springs and Magnetic Damping

In this paper, a two dimensional isolation table using circular arc springs and a magnetic damper, which has a simple construction, low height and the capability of vibration isolation in every horizontal direction, is proposed. The isolation table is composed of eight circular arc springs, twelve free bears, a magnetic damper, a table board and a base board. It has approximately the same stiffness and damping coefficient in every direction in the horizontal plane. The trial isolation table was made and its resisting force characteristics were discussed theoretically and experimentally. The seismic responses and the frequency responses of the table installed a mass or a tower-like structure model were measured using an electrohydraulic-type shaking table. The experimental results were compared with the calculated results, and the effects of vibration suppression of the table were confirmed.

半円弧ばねと粘弾性体を用いた免震・防振テーブルの研究(GS-6 機械工学)

半円弧ばねと粘弾性体を用いた免震・防振テーブルの研究(GS-6 機械工学)

227 半円弧ばねを用いた簡易免震テーブルの研究

In this paper, a two dimensional isolation table using semicircular arc springs and a magnetic damper which has a simple construction, low height and the capability of vibration isolation in the horizontal direction, is proposed. The trial isolation table was made, and the seismic and frequency responses of the table installed a mass were measured using an electrohydraulic-type shaking table. The experimental results were compared with the calculated results, and the effects of vibration suppression of the table were discussed.