Steel Spring Research Articles

Терміни ремонтних робіт та прогнозування строків служби контактів розбірного типу за умов неповноти вихідної інформації

Collapsible contact joints are the most numerous elements of electrical installations. The efficiency of the contacts, their reliability to a large extent depends on the modes of electric current and temperature, contact pressure, etc. Modification of modes and operation time lead to an increase in the resistance of the contacts, the temperature of their heating and possible thermal destruction. Traditional means for controlling the pressure in the contacts when changing the temperature regime are steel plate springs. Previous investigations have established that these means only partially solve the problem of regulation of contact pressure. An alternative to traditional means is the innovative development of dynamic pressure control tools based on the use of functional alloys with the shape memory effect. The mathematical analysis of terms of carrying out repair works and service life of collision type contacts with the use of probability theory in the conditions of incompleteness of the initial information is carried out. The research substantiates that the use of dynamic method of control of the thermomechanical regime of collapsible contacts allows to stabilize pressure and extend the life of collapsible contacts by 3-4 times.

Design of a Dynamic Force Measurement System for Training and Evaluation of Suture Surgical Skills.

The aim of this study is to present the SurgeForce system, a tissue handling training device for analysis of dynamic force applied to the tissue and objective assessment of basic surgical skills during the suture process. The SurgeForce system consists of a mechanical base formed by two platforms joint with three stainless steel springs and a three axial digital accelerometer attached to the upper platform, which detects the dynamic force caused by a surgeon when performing a suture task over a synthetic tissue pad. Accelerometer data is sent to a control unit where preprocessing to transform the raw data into a force signal is done, and then, the force signal is sent to a computer application, which register the force exerted over the synthetic tissue pad. For validation, 17 participants (6 surgeons and 11 medical students) performed three simple interrupted sutures with knot tying using the SurgeForce system. Ten force-based metrics were proposed to evaluate their performance during the suturing task. Results of the validation showed statistical differences in 8 of 10 force-based parameters for assessment of basic surgical skills during the suture task. The SurgeForce system demonstrated its capacity to differentiate force-based performance of surgeons and medical students. The SurgeForce system has been successfully validated. This system was able to distinguish force performance between experts and novices, showing its potential to distinguish surgeons with basic suture skills from those who are not yet prepared.

SOME STUDY ON FATIGUE LIFE OF OPEN COIL SUSPENSION SPRINGS

A helical compression spring being an important part of the vehicle suspension system absorbs energy and shocks that are received by the wheel from road irregularities. Helical compression spring in a suspension system supports the loading effect on the system. It is subjected to different influences of stress and fatigue. The four springs; one at each wheel of vehicle, are subjected to road conditions and driving movements. it is necessity to check the stress, factor of safety and fatigue strength of spring and other parts of the suspension system. The fatigue life of the helical compression spring is significantly affected by physical and chemical properties of the materials that make each component of the vehicle suspension system. The main purpose of this work is focus on the fatigue life of spring used in light vehicle suspension spring with different materials. Results obtained using analytical procedures are compared with those obtained using FEA. From estimation of fatigue life of Chrome Vanadium, Chrome Silicon and Hard Drawn alloy steel spring FEA approach gives fatigue life are 9x 106, 5.0108x107 and 1.484x103 cycles respectively.

Simulation Based Mold Design Optimization of a Spring Flap Casting

The complex nature of metal casting process brings about a need to simulate it before undertaken in a foundry. Casting simulations provide insights on flow of molten metal within the mold, solidification sequence, nature and location of defects etc. Moreover, mold design can be optimized to minimize defects without undergoing physical trials-and-errors as previously practiced in traditional metal casting. This study is based on casting an ASTM A216 WCB steel spring flap for automotive suspension system using a simulation based optimized mold design. The initial and optimized mold designs are simulated in MAGMASoft for mold filling, solidification, stress distribution and defects prediction. The results of simulations and actual castings are found to be in good agreement. It is concluded that simulations are accurate in modeling casting process and in predicting defects followed by their minimization through mold design optimization. The use of auxiliary components in a carefully designed mold can lead to a nearly defect-free and high quality cast product.

Large thermal hysteresis NiTi Belleville washer fabricated by metal injection moulding

ABSTRACT In this work, Ni49.4Ti50.6 Belleville washers are prepared by metal injection moulding (MIM). The martensitic transition temperatures and service performance of washers were investigated. The thermal hysteresis has reached 63.1–71.6°C, which is much higher than documented data in binary NiTi alloys. Ti2Ni and Ni4Ti3 phase are observed in XRD patterns, which is responsible for the large thermal hysteresis. In the service tests, the restoring forces are higher than 40 kN, which are sufficient to ensure a tight connection of the fasteners. The loop resistance and high-current test have proved the safety of MIM NiTi Belleville washers compared to traditional steel spring washers, which can meet the challenge in complex outdoor circumstances.

RETRACTED: Measurement and analysis of vibration and noise in the ambient environment of metro

Abstract With the development of the metro, the drawbacks such as train-induced vibration and secondary noise have become increasingly prominent. This paper presents the field tests on the ambient environment of certain tunnel sections. The vibration acceleration at different measure points were measured and the corresponding frequency spectra were analyzed, and the acquisition and analysis of secondary noise inside the building located in the noise-sensitive area were carried out so that the characteristics of vibration sources, their corresponding ground-borne vibrations and secondary noise can be investigated. Besides, the effectiveness of different mitigation measures was compared and the environmental amenity was evaluated from different indicators. The results show vibrations in the sections adopted mitigation measures were reduced, especially effectiveness of steel spring floating plate was found to be most obvious. The excessive vibration and sound levels in sensitive area determined that the mitigation measures should be adopted to meet evaluation criteria.

Analysis of Efficiency of Fiberglass Ring and Band Springs

A method of design analysis of a magazine ring and wave band springs of unidirectional, high strength, and low modulus fiberglass is represented. The springs are intended as a spring suspension for vehicles and aircraft. The use of split rings with different gaps makes it possible to obtain a nonlinear change in the compliance of suspension. The effects of the creation of equal strength profiling of wave band springs are analyzed. The replacement of steel springs by composite ones allows manifold weight reduction while maintaining the strength and compliance requirements.

An experimental study on the performance of fine-grained concrete incorporating recycled steel spring exposed to acidic conditions

This article aims to study the effects of adding steel fibers and galvanized recycled spring on mechanical properties and crack development in the fine-grained concrete exposed to the acidic environment containing magnesium sulfate. To this end, specimens containing 0.3% and 0.6% of steel fibers and springs, respectively, by concrete volume, were built in normal temperature using 10 cm × 20 cm standard steel formworks so as to conduct the compressive and tensile strength tests. All specimens were cured in 28 days exposed to the environment containing 0%, 5%, and 10% of magnesium sulfate. Based on the results, addition of steel fibers and recycled spring improves the compressive and tensile strength by 50% and 60%, respectively. Moreover, the specimens containing recycled spring better withstood against the acidic environments in comparison with the specimens including steel fibers. In general, it was found that due to the negligible difference between the strength of the specimens, the application of metal-recycled spring in the fine-grained concrete is technically and economically justifiable.

Characterization of a silicon nitride ceramic material for ceramic springs

Under extreme working conditions such as high temperature, strong electric and magnetic fields and acidic or basic environments, ceramic springs offer a clear advantage over conventional steel springs. In this study, a tailored grade of silicon nitride ceramic was characterized as spring material. The basic characterization was complemented with component tests. Bend bars, helical springs and conical disk springs were manufactured and tested under various loading scenarios.Manifested by the smallest effective volume of the three tested geometries, helical springs showed the highest fatigue strength. Nevertheless, the complexity involved in manufacturing helical springs pertaining to their geometrical features resulted in a relatively large scatter in fatigue data. The results pointed out the importance of proper design and machining of the contact surface edges in disk springs, which bear the highest stresses.This work demonstrates the potential of producing ceramic springs with broad applicability and sufficient strength and fatigue resistance.

Suppression of the Generator Imposition Vibration

<span lang="EN-GB">Generator vibrations occur as a result of unbalanced revolving masses, loading forces and torques, starting and coasting of driving motors and other effects. Suitable mounting of the generator is possible using damping components such as steel springs, pneumatic springs, rubber pads or other damping components. The article describes a numerical calculation of individual deviations of the generator in dependence on time for the given machine parameters and the selected damping components of its mounting using the Matlab program.</span>

Development of a track dynamics model using Mindlin plate theory and its application to coupled vehicle-floating slab track systems

Unlike track slabs in high speed railways, floating slabs in metro lines are usually relatively thicker and their thickness can often reach 0.5 m or more. When the thickness of the track slab is relatively large compared to the length and width, the influence of shear effect and rotatory inertia will become significant and it is more reliable to regard the track slab as an elastic thick plate than adopt the classical thin plate model in the simulation. This paper presents a three-dimensional dynamic model for coupled vehicle-floating slab track (CVFST) systems on the basis of Mindlin plate theory for the first time. The floating slab is described as an elastic rectangle Mindlin plate with free boundary conditions resting on steel springs, the mode shapes of the Mindlin plate are approximated by series of products of Timoshenko beam functions, and the corresponding vibration equations are solved by Rayleigh-Ritz method in time domain. The vehicle subsystem and track subsystem are coupled via wheel-rail nonlinear interactions. The effectiveness of the proposed model is validated by comparing with the measured data from an impact test and numerical results in the previous literature. Influence of size effect on the slab natural frequencies and dynamic responses of the CVFST system are investigated, and discrepancies of the calculation results between the developed model and the traditional thin plate model are simultaneously discussed. Some practical conclusions are drawn and the developed model may serve as a potent tool for more accurate assessment of train-induced vibrations in metro lines.

Vertical Dynamic Analysis of Ballastless Tracks on Train-Track- Bridge System

In order to investigate the vertical dynamic response characteristics of train-track-bridge system on CWR (Continunously Welded Rail) under dynamic load of train on HSR (High-Speed Railway) bridge. Based on the principle of vehicle train-track-bridge coupling dynamics, taking the 32m simply supported bridge of a section of Zhengzhou-Xuzhou Passenger Dedicated Line as an example, the finite element software ANSYS and the dynamic analysis software SIMPACK are used for co-simulation, and bridge model of the steel spring floating slab track and the CRTSIII ballastless track (China Railway Track System) considering the shock absorbing steel spring, the limit barricade and the contact characteristics of track structure layers are established. On this basis, in order to study the dynamic response laws of the design of ballastless track structure parameters to the system when the train crosses the bridge and provide the basis for the design and construction, by studying the influence of the speed of train on the bridge, the damage of fasteners and the parameters of track structure on the train-track-bridge system, the displacement of rail, vertical vibration acceleration and wheel-rail force response performance are analyzed. Studies have shown that: At the train speed of 40 km/h, the displacement and acceleration of the rail and track slab in the CRTSIII ballastless track are smaller than the floating slab track structure, but the floating slab track structure has better vibration reduction performance for bridges. The acceleration of rail, track slab and bridge increases obviously with the increase of train speed, the rail structure has the largest increasement. Reducing the stiffness of fasteners could decrease the vertical acceleration response of the steel spring floating slab track system, the ability to absorb shock can be enhanceed by reducing the stiffness of the fastener appropriately. Increasing the density of the floating slab can increase the vertical acceleration of the floating slab and the bridge, thereby decreasing the vibration amplitude of the system.

Spiral stir bar sorptive extraction with polyaniline-polydimethylsiloxane sol-gel packings for the analysis of trace estrogens in environmental water and animal-derived food samples.

A spiral stir bar was proposed by using stainless steel spring as the extraction phase carrier to avoid the extraction phase friction and increase the amount of extraction phase for improving extraction efficiency. The extraction phase is filled in the cavity of the spring, resulting in a larger amount of the extraction phase than that conventionally coated on glass stir bar or stainless steel wire. Polyaniline-polydimethylsiloxane sol-gel packed spiral stir bar was prepared and evaluated for the extraction of five estrogens. The prepared spiral stir bar presented good extraction efficiency/preparation reproducibility and long lifetime (more than 150 reused times) for target estrogens. Based on it, a method of spiral stir bar sorptive extraction combined with high performance liquid chromatography coupled with ultra-violet detection was developed for the analysis of trace estrogens in environmental and food samples. The detection limit for five estrogens was 0.11-.31 µg/L, with the enrichment factors of 83.0-118-fold (maximal enrichment factor: 200-fold). The reproducibility evaluated with each estrogen of 5 µg/L (n=5) was 5.8-8.9%. The method was successfully applied for the determination of estrogens in environmental water and animal-derived food samples.

Fabrication and analysis of Master leaf spring plate using carbon fibre and pineapple leaf fibre as natural composite materials

This paper deals with fabrication and analyse of parabolic leaf spring plate made up of carbon fibre and pineapple leaf fibre as composite materials. The automobile trade has shown keen interest for replacement of steel spring plate thereupon of composite spring. The stuff has high strength to weight ratio, smart corrosion resistance and tailorable properties. The spring plate is fabricated by open moulding method with three different materials. The primary layer of the fabric is carbon fibre mat and second layer is created of epoxy or polyepoxide, which is placed over the carbon fibre layer. The third layer made from pineapple fibre mat. A comparison has been made between composite fibre and glass fibre reinforced leaf spring plate with regard to compression strength, impact strength and Brinell hardness. The result shows that leaf spring plate made up of carbon fibre and pineapple leaf fibre composites are lighter weight and better strength than the epoxy glass spring. Potential materials are determined to replace these metallic leaf springs plate while not relinquishing strength and well raising structural weight.

Experimental Study on the Damping Effects of Various Vibration Reduction Measures

Field measurements are the most effective and direct way to evaluate the effects of vibration reduction measures. Through field measurements, this study examined the actual damping effects and vibration transfer characteristics of five vibration reduction measures for subway systems, namely, steel spring floating slabs, resilient short crossties, double-layer nonlinear damping fasteners, Vanguard fasteners and rubber floating slabs. The vibration level and 1/3 octave frequency division vibration level was used as vibration evaluation indices for analysis. This study aimed to provide a reference for the actual damping effects of vibration reduction measures. The results show the following: steel spring floating slabs outperformed resilient short crossties by 23.2 dB. Double-layer nonlinear damping fasteners outperformed Vanguard fasteners and rubber floating slabs by 1.6 and 2 dB, respectively. Resilient short crossties, Vanguard fasteners and double-layer nonlinear damping fasteners were effective in reducing vibration from steel rails to track beds (floating slabs). Steel spring floating slabs and rubber floating slabs were effective in reducing vibration from track beds (floating slabs) to tunnel walls.

Rational Drawing Condition Choices of Thermally-Treated Steel Spring Wire

The computer-simulated normal stress distribution in the working zone of the draw die and the dependence of its magnitude on various drawing parameters is given. Derived from the data and previously developed procedures for the evaluation of the metal’s stress state in the deformation zone, the operative wire drawing sequence is analyzed and improved, which is focused on subsequent quenching and tempering. The industrial experiment results confirm the performance of the new drawing sequence during the fabrication of thermal-treated spring wire.

Optimization of a mono-composite leaf spring using a hybrid fiber-layup approach

Conventional leaf springs are simple in design, utilizing multiple metallic bars (leaves) with low geometrical moment of inertia to generate an economical and linear spring rate. In its early form, the leaf-spring was manufactured using metals like steel, but, in modern applications, there exist composite leaves reinforced by advance glass and carbon fibers. Benefits of composite spring designs include: high specific strength, ability to form complex profiles, and possibility of subcomponent consolidation to reduce assembly. Due to the bending characteristics of the leaf spring, the axial load decreases through the beam thickness, reaching a minimum at the neutral surface. Given this fact, a design optimization approach for mono-composite leaf springs is developed considering a hybrid fiber-layup. Initially, a detailed topology optimization is conducted to optimize the geometry of the leaf spring based on the Tsai-Wu failure model. This process yielded a unique spring design which reduced the mass of the spring by 29% compared to the initial non-optimized spring and 80–90% compared to a steel spring. Subsequently, the design is further optimized by replacing low stress, high modulus reinforcement with lower modulus and cost-effective materials to improve overall vehicle mass, efficiency, and operation. The second stage of the optimization based on the hybrid fiber-layup approach resulted in an additional 7% mass reduction. As there is a connection between fuel efficiency and vehicle mass, the significant reduction of spring mass has a positive impact on vehicle fuel consumption and leads to suspension responsiveness gains. Moreover, the possibility of swapping up to 20% of the middle plies reinforcement with commodity plastics demonstrates the cost benefits of the hybrid fiber-layup design approach considering the high cost of carbon and other high-performance reinforcements.

An Exploratory Study Comparing the Hand Arm Vibration Exposures Measured from Bucking Bars using Traditional Tool-mounted Accelerometers and Wrist Worn IMUs

This controlled, exploratory laboratory study was conducted to measure hand-arm vibration (HAV) exposures when using a bucking bar fitted with three different handles: 1) a typical plastic handle, 2) a similarly designed handle with an aluminum core and a built-in dampening spring, and 3) a steel core handle with the same built-in spring. Using two experienced machinists, tri-axial HAV exposures were measured at the bucking bar handles; small, battery-powered, self-contained Inertial Measurement Units (IMUs) were used to measure the vibration transmitted through the tool operator’s left and right arms; and a wearable device worn on the operator’s right wrist estimated the HAV exposures occurring at the tool handle. The plastic handle produced the highest HAV exposures while the aluminum-spring and steel spring handles reduced exposures by 19% and 39%, respectively. On average, 74%, 65% and 40% of the tool-measured vibration was transmitted to the right hand, forearm and upper arm, respectively. The wrist mounted sensor appeared to accurately estimate HAV exposures measured at the hand-tool interface.

The effect of factors on the flexural of the composite leaf spring

Abstract The modern automobile industry is heading into reducing the weight of vehicles in-order to reduce the fuel consumption of the modern vehicles, for that reason composite materials have gain special position when developing vehicles. This paper studied leaf spring, which is one of car part that can be manufactured from composite material, the material used at this research was E-glass fiber with polyester and epoxy matrices. experimental work showed the relation between load capability and the fiber distribution within the composite, having a better load bearing capability for material made from woven fiber. Additionally, the increase of fiber fraction in composite will improve its mechanical properties. Moreover, the type of matrix used in manufacturing the composite had a significant factor on material stiffness, where the mechanical properties of composite with epoxy matrix improved and increased the weightlifting ability more than a matrix made from polyester. Furthermore, the composite leaf spring has nearly the same stiffness of steel when its thickness 11 mm, while the thickness of steel spring is 5 mm. The reduction of weight in composite spring is 84% lower than steel spring.

Enhancing the actuation frequency of shape memory alloy wire by vibration-enhanced cooling

Shape memory alloy wire actuators are lightweight, compact, and have high actuation stress, but their actuation frequency is limited by the rate they can be thermally cycled. Heating time can be reduced with high current, but rapidly cooling the material without introducing disadvantages is a challenge. This study establishes the feasibility of a novel approach to more rapidly cool shape memory alloy wires based on inducing their first mode of vibration. To achieve this, a steel spring pin placed on the wire was driven by an electromagnet as the shape memory alloy cooled. Experiments were conducted with a shape memory alloy wire (250 mm length, 0.381 mm diameter, 70°C austenite finish temperature) that was thermally cycled against constant forces and against an extension spring. The heating and cooling times were measured for the vibrating and non-vibrating trials to determine the factor of actuation frequency increase, which ranged from 1.55 to 2.10. A model of cooling time was developed and compared with the experimental results, with percent errors ranging from 5.3% to 32.8%. The approach was demonstrated in an application: a shape memory alloy–driven rotary ratcheting mechanism, with which factors of actuation frequency increase greater than 1.80 were measured due to vibration-enhanced cooling.