Steel Spring Research Articles

Influence of the cutting edge preparation of carbide punching tools for punching of ultra-high strength steel strips

In order to ensure a robust punching process of ultra-high strength steel spring strips using carbide punching tools, a high stability of the cutting edge is required. Here the cutting edge preparation process has a significant influence. In the presented study, high-pressure abrasive water jet technology for cutting edge preparation was designed, investigated and analysed. For defining the optimal cutting edge shape regarding stresses, a numerical analysis using LS-DYNA was conducted. Within this analysis, the influence of the cutting edge rounding and symmetry was numerically tested and evaluated. Based on the results, two cutting edge shapes were selected and prepared using the high-pressure abrasive water injection jet technology. The tools were applied in the punching process up to 50,000 strokes in order to analyse the cutting performance and tool wear. With regard to a highly wear resistant tool for punching, a combination of the abrasive water injection jet preparation routine and a CVD diamond coating are under further investigation and first insights are presented additionally.

钢弹簧浮置板轨道减振效果现场与实验室测评研究

钢弹簧浮置板轨道减振效果现场与实验室测评研究

Investigation on the effects of changing automotive vehicles leaf springs from steel to hybrid polymer composite leaf springs

Weight reduction is a critical factor in the vehicles and numerous researchers worked on better materials and design optimization to achieve that goal. This paper is focused to design a natural fibre reinforced hybrid polymer composite mono leaf parabolic spring to replace the existing steel multi-leaf semi-elliptical spring in an attempt of reducing the unsprung mass and to investigate its characteristics. The spring so designed is analyzed for its deflection and stiffness, by Virtual work method, whose complex integral was solved numerically by Gauss Quadrature. Along with this, SolidWorks was used to construct a model and ANSYS tests were used to compute the deflection, analyze the stress pattern and verify that the fail proof condition is met. Subsequently, three prototypes of the springs were fabricated by hand lay-up method. These springs were subjected to a static load test which results in deflection values similar to that of laminated steel springs with an appreciable 83 percent weight reduction. Modal Analysis conducted ensures that the fundamental frequencies of different modes are conveniently away from values of human discomfort and also from the nominal driving engine speed of 2000 rpm. The responses to harmonic disturbances which were studied experimentally, analytically and by ANSYS which indicates that vibration amplitudes due to average road undulations are under control, limiting the amplitude within 12 mm. The newly designed spring shall be recommended as a potential replacement, which can further be augmented by future works to be carried out on pot holes and studying the force transmitted on to the vehicle.

Assessment and Control of Metro-induced Vibration and Secondary Noise of TOD Buildings

Metro-induced vibration and structural secondary noise are becoming increasingly outstanding, which greatly restrict the further development of TOD (Transit-oriented development) project. To solve this problem, an evaluation methodology and dynamic model of vibration and secondary noise induced by metro train is developed firstly. Then the characteristic and distribution of vibration and secondary noise of the TOD subject to running train are studied. Finally, the control effect of steel-spring floating slab track (FST) on vibration and secondary noise of TOD project is evaluated. Results show that: when evaluating environmental problem caused by metro train, the standard of secondary noise is more strict than that of vibration. Main frequency of metro-induced vibration is concentrated in 40–63 Hz, and the second main frequency is concentrated in 6.3–16 Hz. The business building has the largest vibration due to its closest distance to the metro line. Secondary noises of most of the TOD buildings exceed the limit value, and the maximum exceeding value is 11.7 dB(A). FST is effective in controlling train-induced vibration and secondary noise of TOD buildings. FST cannot reduce vibrations in full frequency band, and vibration in some frequency bands are even amplified according to the stiffness of steel spring.

Airless tires in the LEON-T project: How can they reduce tire/road noise emission

For more than a century, pneumatic tires (inflated with air) have totally dominated the market for road vehicle tires. However, in the recent two decades, interest has grown in developing airless tires; tires whose load is not carried by the inflation by air, but by the mechanical structure that connects the belt and rubber tread with the hub. The EU project LEON-T includes a part in which prototypes for innovative heavy goods vehicle (HGV) tires are developed, with the main purpose to reduce noise emission by 6 dB. To reduce noise that much it is believed that airless tires are needed. In LEON-T, two airless tire prototypes are intended to be developed by partner Euroturbine, in cooperation with other partners and subcontractors. Originally, the load-carrying material was intended to by composite material (reinforced plastic), but initial calculations have shown that a stronger material is needed; consequently, steel springs are currently being used. This paper will describe the principle of airless tires but with focus on the version being developed in LEON-T. The main part of the paper will deal with the noise generation mechanisms and the ways that airless tires can reduce the noise emission are thoroughly identified and discussed.

Numerical investigation on the failure mode of the upper shear hinge in steel spring floating slab track

Fracture on hinge bars and fixed bolts of upper shear hinges is a common problem in prefabricated steel spring floating slab tracks (SSFST), adversely affecting train operation safety and comfort. To investigate the potential failure modes, this paper established a four-slab SSFST model to analyze the force condition of upper shear hinges. Force transmission between floating slabs as well as the stress level of the hinge bars and fixed bolts under the most unfavorable vehicle cases were respectively simulated by the structural mechanics method (SMM) and the FEA software ABAQUS. Stress influence lines of hinge bars and fixed bolts under the moving vehicle load resulting from ABAQUS were extracted to evaluate the fatigue behavior based on the fatigue S-N curve by the post-processing software FE-SAFE. Furthermore, the influence of different pre-tightening force on fixed bolts’ fatigue behavior was discussed. The results of the two simulation methods match well, suggesting that force between floating slabs is mainly transmitted by rails, while shear hinges only account for about 1/3 of the bending moment and 1/5 of the shearing force. Hinge bars and fixed bolts are both sufficient in strength, yet fatigue problem is likely to happen to the latter. The fatigue failure mode and location of fixed bolts are related to the value of pre-tightening force. Large stress range or high stress mean always exists as the pre-tightening force varies, meaning that bolt fatigue is an intrinsic failure mode of the upper shear hinge in SSFST.

Research on the mechanism of rail corrugation of steel spring floating slab track on metro

Steel spring floating slab track (SSFST) is an effective vibration and noise reduction measure, which is gradually used in urban rail transit in recent years. In order to better solve the problems of vibration noise and abnormal rail corrugation on metro lines, the dynamic model of vehicle-track system including metro vehicle and track structure is established by using the simulation software. The relationship between the passing frequency of vehicle and the vibration frequency of track structure, as well as the resonance characteristics of the elastic track structure are analyzed so as to obtain cause of rail corrugation on SSFST. The results show the following: (1) It is a more obvious resonance phenomenon between the inner rail and the floating slab at the vibration frequency of 116 and 161 Hz (R300 m), 262 Hz (R1000 m) and 320-387 Hz (R1500 m), and the simulation of rail corrugation wavelength is closer to field measured data. (2) Comparing the vibration frequency distribution of ordinary track and SSFST under the same curve radius, the rail corrugation is related to the natural vibration characteristics of track structure. (3) The vibration characteristics of the track structure and the periodic wear characteristics of the rail are the key factors for the formation of rail corrugation.

Improving the Sealing Efficiency of Compressor Cylinders of Gas Engine Compressors in the System of Gas-Lift Production of Offshore Fields

An increase in the efficiency of gland seals in compressor cylinders with cast iron rings pressed against the contact surface of the piston rod using a steel spring in reciprocating compressors used in offshore oil and gas-condensate fields for gas-lift oil production systems is considered. Studies of a gas engine reciprocating compressor working directly on the operating gas-lift system have shown that in order to increase the time of normal operation of gland seals, it is necessary to adjust the clearance using lubricant up to 0.1 mm. After increasing the spring stiffness, the serviceability and number of working hours of the gland seal increased twofold, from 850 to 1700 h.

Component Mode Synthesis Based on the Energy Method for Frequency Domain Dynamic Response Analysis of Ballastless Track Structure

Used extensively in structural dynamics analysis, the energy method is advantageous for transforming boundary value problems of differential equations into variational extremum problems. Recent applications include analyzing the wave and vibration characteristics of track structures. However, traditional energy methods for dynamic modeling and analysis of ballastless track structures require obtaining the global stiffness matrix and mass matrix of the entire coupled system, which decreases computational efficiency. The EM-CMS algorithm for frequency domain dynamic response analysis of ballastless track structures has been proposed to address this issue. The core of EM-CMS is the development of model reduction strategies within the framework of the energy method to reduce matrix dimensions and thereby improve computational efficiency. Specifically, the steel spring floating slab track is the focus of this research. Utilizing the energy functional variational method, the modal properties of the rail and floating slab structures are obtained, and truncation is performed. A reduced-order model for the steel spring floating slab track is established by considering the boundary conditions between the rail-floating slab and the floating slab foundation (connected through fastener springs and steel springs, respectively, and considering the springs’ elastic potential energy). Comparatively, the computational efficiency of EM-CMS is approximately ten times greater than that of the energy method. The method’s accuracy is also carefully validated against finite element simulations.

Effect of novel phononic crystals vibration isolator on vibration reduction for floating slab track considering the random dynamical load of the vehicle

ABSTRACT The vibration caused by urban rail transit has led to numerous severe environmental issues. The floating slab track (FST) plays an important role in vibration control and noise reduction for rail transit. In this study, a novel phononic crystal vibration isolator (NPCVI) is developed based on the principle of local resonance to address the deficiencies in the low frequency vibration reduction of existing FST with steel spring vibration isolators (SSVI). The vibration equation of the NPCVI is derived and an analytical method for the dynamic interaction between vehicle, track, and tunnel is proposed. The pseudo excitation method (PEM) is introduced to solve the random vibration response of the vehicle-track-tunnel coupled system under the excitation of full-band track random irregularity. The numerical simulation results are compared with the field measurement results to verify the correctness of the solution model. The vibration reduction analysis of FST using NPCVI is conducted within a system dynamics framework, and a comparison is made between the performance of the conventional SSVI and the proposed NPCVI while a train is passing. The vibration reduction optimization effect of the NPCVI is evaluated using the vibration level (VL) of the tunnel structure. The results demonstrate that the NPCVI exhibits a superior band gap width as compared to that of the SSVI.

A new design of seat suspension using different models of negative stiffness structure

Three models of seat suspension using the negative stiffness structure including steel springs (SS), roller springs (RS), and tuned mass damper (TMD) are proposed and studied to improve the driver's seat ride comfort. Based on the dynamic models of the SS, RS, and TMD, their isolation efficiency and driver’s ride comfort are evaluated via two indexes of the root mean square displacement and acceleration of the seat (zws and aws) under two excitations of the random road surface and bumpy road surface. The results show that under the random road surface, the zws and aws with the seat's RS are reduced by 10.31 % and 20.32 % in comparison with the seat’s SS; whereas the zws and aws with the seat's TMD are smaller than that of the seat's RS by 19.15 % and 26.13 %; and the seat’s SS by 27.49 % and 41.15 %, respectively. Besides, the seat's displacement and acceleration responses with the seat’s TMD are also lower than that of both the SS and RS under the bumpy road surface. Therefore, the structure of the TMD should be designed and added to the seat suspension to enhance the driver’s seat ride comfort.

Design and analysis of newly developed two-wheeler shock absorber helical spring

The Elasticity property/Spring theory indicates that a long lasting spring is always showing small deflection and high stiffness and this property makes it comfortable for any applications. The present investigation deals with a comparative analysis carried out on the basis of sustainability of helical spring that is extensively used in suspension system, to increase the work efficiency of the shock absorber. A suspension system or a shock absorber is a mechanical device that is used to absorb shocks when riding in rough terrains. Stainless Steel grade (AISI316 & AISI302), High Carbon Steel (Music wire grade ASTM A228 & Hard drawn grade ASTM A227) and Alloy Steel (Chrome vanadium grade ASTM A231 & Chrome silicon grade ASTM A401) springs have been utilized throughout the study followed by applying compressive load. In order to enhance the mechanical property of the helical spring, alloy steel based material has been used instead of stainless steel. During this investigation a new shock absorber spring has been designed with the help of Solid Works software and the static structural analysis of the so formed model has been conducted via FEA.

Design and Analysis of Leaf Springs with Structural Steel and Chromium Vanadium Steel

Abstract: Leaf springs are part of the suspension system on most vehicles and add weight to vehicles due to the traditional steel material. The automotive industry is interested in replacing traditional materials such as steel with other materials for various reasons, such as different mechanical properties. Intensive research is being carried out into replacing the leaf spring with a composite material. The composite material meets various test requirements of automotive standard due to its good elastic properties, high strength-to-weight ratio and lighter weight than steel. The purpose of the article is to focus on various topics such as weight, stresses during construction, modelling and experimental testing of composite leaf springs. In this work, the stress and deflection analysis of the leaf spring is calculated using the finite element method. Leaf springs are analyzed for stress and deflection in ANSYS 14.5. The results show, based on various calculations and observed data that with similar load capacities, induced stresses and deformations are minimized by replacing the steel leaf springs with fibre composite leaves. The analysis was performed considering the leaf spring engine model with the same dimension geometry to reduce the leaf spring weight. A composite material is chosen for the leaf spring. The analysis was performed on the ANSYS 14.5 spring with the same load condition as the steel and composite leaf springs in terms of strength and weight. From the static analysis and test results, after the design change and stress analysis, the composite leaf springs were minimized by about 71.73% and the stress was reduced by 50-80%.

Gurson-Tvergraad-Needleman model-based damage analyses of stainless steel springs at high temperature

In this paper, the Gurson-Tvergraad-Needleman (GTN) model is used to study the damage of stainless steel springs at high temperatures. The basic material and GTN damage parameters are determined from the stress-strain curves of tensile tests. Then the damage evolution of springs at 300 °C to 900 °C is analyzed based on finite element simulations. The results show that below 600 °C, the change of volume fraction of holes in the spring, along with the increase of load, has an obvious low growth stage, followed by a rapid growth stage. But above 600 °C, there is only a stable and rapid growth stage. The fracture positions predicted by finite element damage analyses agree with the experiments for round bars.

EXAMINATION OF COMPOSITE DISC SPRINGS

This study aims to produce composite disc springs from carbon prepreg material, which is close to the characteristic curve of the steel disc spring or better than steel, which constitutes a group of machine elements. In this way, the design will be lightened without significantly diverging from the force/deformation ratio of the disc spring. For this, first of all, a standard steel disc spring was selected, and its characteris-tic curve was determined by the finite element analysis method. For the composite disc springs to be pro-duced, the selected steel disc spring geometry was taken as reference, and different cone heights (taper angles) and different orientation angles of the carbon prepreg layers were determined as variable parame-ters. For all these parameters, finite element analyses were made for the carbon prepreg material in the ANSYS Workbench module, and the disc springs de-signed using these analyses were produced by the autoclave method in a closed mold and tested. As a result of compression tests, spring characteristics of steel and composite disc springs were obtained and compared. The results reveal that composite disc springs produced in certain parameters have more suitable characteristics than steel disc springs.

Methods of reducing the negative impact of resonant oscillations on the quality of concrete products during their vibration compaction

Problem. Most of the equipment for vibroforming of concrete in the production of concrete construction products uses a "over-resonant" mode of operation. The system goes through resonance during acceleration and also before a complete stop. This is detrimental to the products, as newly formed products suffer from resonant oscillations. Goal. The goal of the research was to investigate ways to reduce the negative impact of negative resonance oscillations on products by reducing the time spent in the resonance mode and reducing the amplitude of oscillations. Methodology. The computational and analytical method of finding dependence, a comparative analysis of engine designs and experimental strain-metric studies of two designs of vibration platforms were applied. Results. The value of the angle forming the sector unbalance is substantiated both for the variant without the hub on the unbalance and with it. From the standpoint of minimizing the moment of inertia of the rotor, the expediency and perspective of using a hydraulic motor instead of an electric asynchronous motor has been proven. Other advantages of the hydraulic motor over the electric motor for vibrating machines and vibropresses with frequent transient processes (start-stop) are substantiated. It has been proven that the use of rubber elastic elements instead of steel springs in systems with frequent transient processes may be more appropriate. The amplitude of resonant oscillations in a vibration system with rubber elastic elements is smaller, and the transition through resonance occurs faster. Originality. Ways to reduce the negative impact due to resonance are considered comprehensively. Vibration studies were performed on two vibration platforms with different types of elastic elements. Practical value. Reducing the intensity and duration of resonant oscillations in over-resonant technological equipment for forming building products will positively affect the quality of products. The application of the proposed design features will improve the working conditions of workers and the reliability of equipment.

Vibration attenuation performance of isolator based on locally resonant phononic crystal via train load

A locally resonant phononic crystal isolator (LRPCI) that the external ring vibrators attached to the central connectors through the rubber is designed, and it is installed to attenuate vibration under the track of rail transit. The energy band structure of the isolator is calculated by the finite element method, and its bandgap range is from 49.7 Hz to 104.9 Hz. The transmission loss and the equivalent mass density are further calculated to verify the accuracy of the bandgap, and they are perfectly corresponding to the bandgap. Then, the vehicle-rail-floating slab track-tunnel multibody dynamic model is built to analyse the vibration attenuation performance of the floating slab track installed the LRPCI and steel spring isolator under the train load. The results show that the LRPCI has a low frequency bandgap and can reduce the low frequency vibration, and the vibration isolation performance of the LRPCI is better than that of the steel spring isolator. The LRPCI has a low frequency bandgap, which can isolate the vibrations caused by wheel-rail interaction, and further reduce the impact of vibrations on surrounding buildings and the environment.

To the selection of shock absorber elements of the artificial foot

Introduction. Walking on a prosthesis of the lower limb is accompanied by a shock load on the artificial foot, which provokes discomfort when using the product and pain in the stump, increases the risk of trauma to the skin and the formation of arthrosis of the joints of the lower limb. These negative consequences can be reduced by the use of prosthetic modules with shock-absorbing properties. Usually, the artificial foot plays the role of a shock absorber in the prosthesis.Aim – substantiation of the choice of material for the shock-absorbing module of the artificial foot.Materials and methods. Bench tests of leaf springs made of steel, carbon and titanium alloy of different thicknesses were carried out by registering changes in their geometric characteristics under a dosed load, as well as full-scale tests of experimental artificial feet with such springs used as a load absorber. The functionality of the feet was determined by the subjective assessment of the comfort of the prosthesis by the patient and the result of the analysis of pressure dynamics under the feet. Results. The results of bench tests showed that leaf springs made of steel 2 mm thick, titanium alloy 3 mm and carbon fiber (carbon) 5.7 mm are unsuitable for use as a shock absorber in the foot of the prosthesis in terms of deflection in the longitudinal and transverse directions under load, in contrast to springs made of 3 mm steel and 4 mm titanium alloy. Field tests of experimental feet with shock-absorbing modules made of steel 3 mm thick and titanium alloy 4 mm showed their suitability for use as part of a prosthesis, which was confirmed by a positive assessment of their comfort by patients, as well as an increase in the symmetry coefficient of the duration of the roll over the artificial and intact feet when walking with experimental foot design compared to industrially manufactured.Discussion. The 4mm titanium alloy leaf spring outperforms the 3mm steel spring in terms of buckling under load, but biomechanical studies have not shown a clear preference for the experimental foot with one of these materials over the other. At the same time, each of them turned out to be more functional than the commercially manufactured foot chosen for the study. But the high corrosion resistance and low specific gravity of the titanium alloy, higher mechanical strength per unit mass compared to steel, give advantages to this material for the manufacture of shock-absorbing modules in atypical prostheses. The choice of the thickness of the elastic element can and should be calculated taking into account the weight of the disabled person.Conclusion. The manufacture of elastic elements from titanium alloys is promising when used in artificial feet for atypical prostheses that require high corrosion resistance and mechanical strength with a small mass of the product. A positive factor in the use of titanium alloys for the manufacture of foot shock absorbers in the form of leaf springs is the simplicity and low cost of the design.

Design, Analysis and Optimization of a Lightweight Vehicle's Leaf Springs

In recent years, the automobile industry has primarily concentrated on reducing weight and improving ride quality. Because composite materials have a high strength-to-weight ratio, strong corrosion-resistance, and tailorable qualities, Steel leaf springs are being phased out in favour of composite leaf springs in the automotive industry. Three strategies have been investigated to reduce vehicle weight: rationalizing the body structure, using lightweight materials for parts, and reducing vehicle size. This study describes the static and dynamic analysis of steel 55Si2Mn90 parabolic leaf springs as well as composite parabolic leaf springs consisting of E Glass fibre, Carbon fibre, and Kevlar fibre. The goal of this study is to examine the load-carrying capability, stiffness, and weight reduction of composite and steel leaf springs. Dimensions of an existing steel 55Si2Mn90 parabolic leaf spring and a light commercial vehicle's composite parabolic leaf spring are taken. In terms of weight and stress developed, a comparison was made between composite and steel leaf springs. The Kevlar fiber leaf spring, after optimization, is 45.67% lower in weight than other materials and has superior riding quality than a typical steel spring with equal design criteria.

Use of mechanical braking energy in vehicles as electricity and hydrogen energy

The work is devoted to developing a mechanism for returning the mechanical energy expended during braking of the vehicle, lost during transmission to the body and proportional to the loss of volume of the combustible engine. The withdrawal of mechanical energy from the wheel braking system is carried out by a cable having a connection with an additional element between the body and the rotating wheels. This element is an additional weight, which increases the wheel system in insignificant volume and weight - only a few %. The other end of the cable is connected to a special mechanical energy storage spring. The mechanical pulling force of the cable compresses the spring system of the special design and accumulates mechanical energy in a volume of approximately 60–70% of the braking energy. The same end of the cable is also connected to the freewheel clutch and the return spring. After the mechanical energy has been transferred, the cable and the brake disc (additional element) are freely returned to their original position by a return spring. The mechanical energy accumulator is constructed of springs made of good quality steel. It is possible to create a design that stores the energy of all four wheels of the vehicle with a single spring. For the design investigated in the work, a carbon steel spring was selected using the characteristics of this steel. The electric generator installed in the structure, mechanically connected with the mechanical energy accumulator, converts mechanical energy into electrical energy by rotation of the rotor under the action of spring forces. Electricity from the electric generator is directed for collection in the battery banks.