Spring Material Research Articles

Damage to Special-Purpose Ring Wavy Springs under the Influence of Hydrogen Sulfide-Containing Media

Annular wavy springs are widely used in the oil and gas industry and most often serve either as compensators for temperature deformations or for mechanical seals of various joints in equipment transporting oil and gas media. These springs provide high load capacity with a relatively low draft, which ensures a compact design. Most often, such springs are made by stamping from sheet steel. When operating technological equipment that transport hydrogen sulfide-containing oil and gas media, hydrogen sulfide stress corrosion cracking occurs quite often, which can lead to failure of industrial equipment. In particular, damage to annular wavy springs can cause depressurization of elements of industrial equipment and cause significant harm not only to the environment, but also to maintenance personnel. The object of research was annular wavy springs made of steel type X15N7M2YU. The purpose of the study is to determine the resistance of the spring material to stress corrosion cracking. This article discusses the test results of special purpose annular wavy springs in an aggressive hydrogen sulfide-containing medium artificially prepared according to the recommendations of ANSI/NACE TM 0177. The results of hardness studies, strength calculations and metallographic studies of damage to a wavy spring are presented. The chemical composition of the metal of the spring fully corresponds to the steel type X15N7M2YU declared by the enterprise. According to the studies conducted in environments containing hydrogen sulfide, the wavy spring is not recommended for use in oil and gas equipment, since it is not resistant to hydrogen sulfide cracking under stress.

The effect of an auxiliary spring on the decrease of contact resistance and contact temperature for power automotive connector

Power automotive connectors used to connect two electrical systems in an electric vehicle should resist the rising of electric power or electric current. The latter can cause a rise in contact temperature by the Joule effect and can damage a connector improperly designed. The purpose of this work is to study experimentally and numerically the influence of the addition of a second spring on the ability of a power connector to transmit a high current. For this reason, an experimental test has been held on a connector without a second spring to measure contact resistance and contact temperature; then, a finite element model FEM of this connector was developed to compare and validate the numerical results with the experimental results. In addition, another FE model with a second spring was used to minimize contact resistance and contact temperature. Moreover, a theoretical model has shown its effectiveness in contact temperature and contact area calculations; it provides good agreement with experimental and numerical results. Numerical results show that the effect of the addition of a 2nd spring on the decrease of the contact temperature and contact resistance is significant. In addition, the thermo-electrical analysis by finite element shows that the current limit supported by a power connector with an auxiliary spring will equal twice the current supported by a power connector with one spring. FE mechanical analysis shows that the maximum mechanical stress in the connector with an auxiliary spring remains lower than the 2nd spring material yield stress. Finally, experimental and numerical results are in good agreement.

Elastic medium and torsional spring effects on the nonlocal dynamic of functionally graded porous nanotubes

In this study, Eringen’s nonlocal elasticity theory that applies the small size effects in functionally graded porous nanotubes embedded in an elastic matrix is discussed. The material properties of functionally graded porous nanotubes are taken into account to vary over the radius direction with a rule of mixture. The free torsional vibration relation according to nonlocal elasticity theory, via Hamilton’s principle, is obtained and an eigenvalue solution is constructed for the free torsional vibration response of the presented work. The presented analytical model is validated by comparing the calculated mathematical results for homogeneous nanotubes with rigid and non-rigid boundary conditions. Special attention is given to deformable boundary conditions, porosity coefficient, material grading coefficient and also to the influence of elastic medium on the free torsional vibration frequencies. In this paper, it has been proven that the influence of length, elastic medium, elastic torsional spring rigidities, material grading and porosity coefficients on the vary in the torsional vibration frequency of the functionally graded nanotube is not small.

Effect of austenitisation and tempering treatments on the mechanical properties of advanced high strength spring steel SAE 9254

In response to increasingly stringent global regulations within the automotive industry, there is a growing demand for lightweight yet high-strength steel suspension coil springs. This study undertakes a comprehensive examination of the critical factors influencing the mechanical properties of SAE 9254, a well-established spring material, in its quenched and tempered (QT) state. The primary objective is to optimise its strength and ductility, especially in high-performance applications with an emphasis on lightweight design. The investigation encompasses a detailed exploration of the effects of varying austenitisation temperature (AT) and austenitisation time (At) on the microstructure and mechanical properties of the steel. Of particular interest is the study of tempering temperatures ranging between 300°C and 350°C to elucidate the mechanisms responsible for enhancing the steel's strength. Notably, the findings highlight dislocation density as the primary factor driving the strengthening of martensitic spring steel. Furthermore, the pivotal role of austenite grain size before quenching becomes evident, influencing toughness, ductility, martensite block size, and the percentage of retained austenite (γR). This study provides valuable insights into optimising the mechanical properties of SAE 9254 spring steel for high-performance applications, achieving ultimate tensile strengths (UTS) exceeding 2100 MPa and a reduction in area (RoA) exceeding 30%. Notably, the properties attained for this grade are comparable to those achieved with microalloying additions. Consequently, this research underscores the significance of controlling austenite grain size and dislocation density as critical factors for tailoring the properties of martensitic steels, positioning them as competitive materials, particularly in the pursuit of lightweight design.

Effective Computational Model for Determining the Geometry of the Transition Zone of End Coils of Machined Springs, Enabling Efficient Use of the Spring Material.

This paper presents an analysis of the effect of the geometry of the end-coil transition zone on the material stress state of a machined compression spring with a rectangular wire cross-section. The literature relationships for determining the stresses in rectangular wire compression springs neglect the effects associated with the geometry of this zone. A series of non-linear numerical analyses were carried out for models of machined compression springs with a wide range of variation in geometrical parameters. The results of these analyses were used to develop a computational model to estimate the minimum value of the rounding radius ρmin, which ensures that the stresses in this zone are reduced to the level of the maximum coil stresses. The model is simple to apply, and allows the radius ρmin to be estimated for springs with a spring index between 2.5 and 10, a helix angle between 1° and 15°, and a proportion of the sides of the wire section between 0.4 and 5.

Practical fatigue strength diagrams for compression springs based on the FKM-Guideline “Analytic Strength Assessment for Springs“

Metal springs are used extensively in technical products. The mathematical relationships and Goodman diagrams contained in the DIN EN 13906–1 standard form the essential basis for the design and calculation of cylindrical helical compression springs. They are used not only nationally, but internationally in the spring industry and by spring users. However, the diagrams are more than 50 years old and no longer reflect the current status of modern spring materials and spring manufacturing technologies. This results in great uncertainty for users of the standard, which currently has to be compensated by costly fatigue tests.In order to overcome the problems, the research project IGF 19693 aimed to renew the Goodman diagrams of the DINEN13906–1 standard in accordance with the state of spring technology. Therefore, the FKM guideline “Analytic Strength Assessment for Springs and Spring Elements“ was used to calculate permissible fatigue strength values for standard springs. Additionally, an extensive experimental program was carried out with fatigue tests on cold-formed helical compression springs to validate the calculations. The main results of the project are presented in this manuscript, which strengthens SMEs in designing competitive springs, which they can offer in a shorter time and at a lower cost due to lower development costs.© 2024 The Authors. Published by Elsevier B.V.

The Effect of Niobium Addition and Pre-Annealing on the Tensile Properties of 52CrMoV4 Spring Steel.

In this study, the effect of niobium addition and a specific preheating process on the microstructure and tensile properties of 52CrMoV4 steel used in leaf springs was investigated. Flat and leaf spring materials were used to accomplish this aim. The flat materials under investigation were kept in a furnace for 90 min at 900 °C. A homogeneous microstructure was aimed for with the use of this pre-annealing heat treatment in addition to the standard process before rolling used to create NbC. Leaf spring production was carried out with flat materials that possessed various Nb contents, with or without pre-heating. Grain size measurement and tensile tests were performed on the flat and leaf springs. Additionally, scanning electron microscopy images were captured from the fractured surfaces after the tensile tests were carried out. The current study highlights the importance of Nb addition as an alloying element and the effect of the selected pre-annealing process in optimizing the grain structure and enhancing the tensile properties of leaf springs. The leaf spring with a Nb ratio of 0.0376 that was pre-annealed exhibited a finer grain structure (G = 11.3), greater tensile properties (YS = 1550 N/mm2 and UTS = 1688.6 N/mm2), and deeper tear valleys and larger dimples, indicating higher energy consumption during fracturing, according to the SEM images produced, in contrast with the other materials studied.

Study on the influence of spring helix angle increase on stress distribution and fatigue life of the operating mechanism

The spring operating mechanism is the key component of the high-voltage circuit breaker, and its split-closing power comes from the self-energy storage of the split-closing spring, so the performance mechanism and fatigue state of the split-closing spring has a great impact on the operation process and dynamic response of the operating mechanism. In this paper, by increasing the coil angle of the spring, changing the spring design material, classifying and modeling the spring, and applying finite element analysis aim to analyze the static structure. The influence of the change of different spring coil angles and materials on the stress distribution of the spring is explored, and the finite element calculation results are imported into the life analysis module to evaluate the life of springs with different helix angles and materials. The results show that under the action of 9 kN working load, after the helix angle is increased by 0.6°, the spring life decreases by 7.23%, the spring life continues to increase by 0.7°, and the overall life of the spring decreases by 12.3%, compared with the initial state. The life decline curve shows an inverse proportional trend.

Coil Spring Failure Analysis Reviewed from Residual Stress, Crytal Orientation, and Texture

Crystal defects can be identified through the crystallographic characteristics of crystal orientation (lattice), microstrain, and texture. Identification of crystal defects on the atomic scale through crystallography is very important in analyzing the mechanism of material properties due to the influence of dislocations. The slip mechanism is analyzed to minimize coil spring failure. This study aims to analyze the causes of coil spring failure based on crystallography. XRD testing was carried out for analysis of residual stress, crystal orientation, and texture using MAUD 2.94 version software. Hardness testing was carried out on the surface of the coil spring with locations near and far from the fracture using micro Vickers. The macro fracture morphology was analyzed using a DSLR camera and the micro fracture morphology was analyzed using SEM. The XRD result shows that the coil spring material has a tensile residual stress value of "202.4 ± 15.9 MPa" with the resulting crystal orientation showing the hkl (100), (200), (211), (200) fields. The plane (200) has a texture characteristic that is oriented towards the Rolling direction along the spring axis. Texture oriented towards Rolling Direction can be shown with a maximum probability value of 1.191. A high probability will have an impact on the presence of material surface defects. Surface defects are indicated by the presence of pit corrosion on micro and macro fracture morphology observations. The pit corrosion defects that occur in the failed coil springs are the beginning of the formation of crack initiation and cause stress concentration. The stress concentration will increase with loading and cause crack propagation.

Shock Isolation of Light Vehicle Suspension by Modified Eye Leaf Spring

Background: Rickshaws are a popular and inexpensive mode of transportation in Bangladesh for short-distance travel. However, the eye leaf spring in a typical rickshaw suspension system does not provide adequate shock isolation. The coil spring-damper suspension system is more effective, but is costly and not affordable for most manufacturers. Thus, the goal is to modify the eye leaf spring to be inexpensive but a safe and comfortable suspension. Aim: The study aimed to modify the material and structure of the leaf spring to limit the stiffness and the shock energy within a certain range suitable for the rickshaw’s suspension. The focus of the study was on modifying the spring structure, which could be cost-effective. Methods: In this study, flexible bolted joints and EVA sheets have been used to change the spring structure. The study compared the performance of the modified spring with the typical eye leaf spring. Results: The modified eye leaf spring provided improved shock isolation and a more comfortable ride compared to the typical eye leaf spring. The changes made to the spring, such as the use of flexible bolted joints and EVA sheets, limited the stiffness and shock energy within a certain range suitable for the rickshaw’s suspension. The modified spring was also found to be cost-effective. Conclusion: The study has demonstrated the feasibility of using a modified eye leaf spring for light vehicle suspensions, specifically for rickshaws. The modifications made to the spring structure, such as using flexible bolted joints and EVA sheets, provided improved shock isolation, a more comfortable ride, and cost-effectiveness. The modified spring offers an inexpensive solution for manufacturers to produce rickshaws with a safer and more comfortable suspension system.

Surface Plastic Deformation of Spring Materials: Special Features of Structure and Properties

Surface Plastic Deformation of Spring Materials: Special Features of Structure and Properties

Analysis of the Mechanical Properties and Study of Influential Factors of Different Materials in Tape Spring

This paper analyzes and calculates the mechanical properties of composite tape spring structures during folding and bending and establishes a non-linear control equation for the folding and bending of composite laminate tape spring structures. Accurate expressions for folding and bending displacements are obtained. The influence of the cross-section’s central angle and the composite tape spring’s ply thickness on their mechanical properties are analyzed. Finite element numerical analysis is performed on [−45 45]s laminated composite tape springs, and the correctness of the theoretical derivation is proved by comparing the curvature radius-bending moment curve. Based on previous research, the mechanical properties of different tape spring materials and structures are compared, further studying the lightweight design of space deployment mechanisms. The results show that the steady-state bending moment performance of composite tape springs is excellent, with a 162.1% improvement in steady-state bending moment performance per unit mass compared to traditional metallic tape springs. Additionally, the critical bending moment performance of negative Poisson ratio honeycomb structure tape springs is also excellent, with a 62.3% improvement in steady-state bending moment performance per unit mass compared to traditional metallic tape springs.

Making of Pressure Springs From Low Carbon Steel St 37 Material as an Alternative to Standard Pressure Springs in Mold Construction Through Solid Carburation Processes

Compression Spring is one of standard components type that are widely used in machinery construction, as well as in mold construction that serves to restore the position of the ejector mould into position. This study aims to find alternative materials for standard compression spring using specimen test of low carbon steel St 37 in the form of a compression spring is made by using coiling process followed to heat treatment processes such as pack carburizing, hardening, quenching and tempering. To ensure the quality process, the tests should be done in the laboratory such us the hardness test, the distribution of hardness, microstructure and deflection of the spring test. The pack carburizing is done at a temperature of 925ºC with a holding time of 2.5 hours, followed by a case hardening process at a temperature of 870ºC with a holding time of 12.5 minute and quenched on medium oil and tempered at a temperature of 350ºC. The results of this research show that the method used to generate the average value of 456.57 HV and have ? – martensite microstructure and also the compression spring deflection average value of 18.625 N/mm on 613.9 N. Those data approaches the compression spring standard value of hardness, microstructure and deflection. Based on the data analysis, low carbon steel St 37 can be used as alternative material for standard compression spring.

Thermodynamic models of the air spring on the high-speed pantograph

ABSTRACT The modelling method of the air spring and its additional pneumatic system has been studied more frequently in recent years. As for the railway field, the study of the secondary suspension system of the bogie is the most popular, while little focus is on the air spring of the pantograph. In this paper, the modelling method of the air spring on the pantograph is investigated and developed. Four thermodynamic models are derived step by step, which can roughly be separated into two types. The first two models are established to express the relationship between the inner pressure and the vertical displacement of the air spring, and the effect of a regulator is illustrated and discussed. The latter two models that are developed from the first two models are set up to express the relationship between the vertical force and the vertical displacement of the air spring, where the effect of air spring material is illustrated and discussed. All four models are validated by comparing the simulation results with experimental results for frequency characteristics. Finally, the characteristics of the four proposed models are illustrated and discussed.

Design and characterize of kirigami-inspired springs and the application in vertebrae exoskeleton for adolescent idiopathic scoliosis brace treatment

Adolescent idiopathic scoliosis is a common condition that affects children between the age of 10 and young adulthood. Rigid brace treatment is an effective treatment to control the progression of spinal deformity. However, it limits mobility and causes discomfort, which leads to low treatment compliance. In this study, we developed and characterized a kirigami-inspired CT/MRI compatible spring that could be employed to modify our previously designed exoskeleton hinge vertebrae to provide immediate in-brace correction, good wear comfort, and one that does not inhibit mobility simultaneously. Additive manufacturing has drawn significant interest in academic and industrial terms due to its ability to produce geometrically complex structures. The structural design and dimension of the proposed 3D printed kirigami-inspired springs were optimized with the finite element method (FEM). The carbon-fiber-reinforced nylon material (PA-CF) was selected as the material of the kirigami-inspired spring with the balance of printing easiness and performance of the material. The stiffness of designed kirigami-inspired springs varied between 1.20 and 42.01 N/mm. A case series study with three scoliosis patients has been conducted to investigate the immediate in-brace effect on reducing the spinal curvature and asymmetry of the body contours using radiographic examination. The experiment results show that there are 4.6%–50.5% improvements in Cobb angle for different sections of spines. The X-ray images proved that our kirigami-inspired springs would not block views for Cobb angle measurements.

Multi-blade monolithic Euler springs with optimised stress distribution

Euler springs are used for vertical suspension and vibration isolation as they provide a large static supporting force with a low spring-rate and use minimal spring material. To date, multiple single-width rectangular blades of uniform thickness and stacked flat-face to flat-face have been used in the post buckled state, with half of the blades buckling in each of opposing directions. For ultra-low-noise isolation the ends need to be clamped which results in stick–slip issues at the joints. In this study we investigate the benefits of forming side-by-side oppositely buckling blades from a single monolithic sheet of spring material. Additionally, we study how to distribute the stress evenly along the length of the blade by contouring its width, as well as finding the optimal contour to distribute the stress evenly around the tearing joints between oppositely bending blade sections. We show that this optimal shaping typically improves the inconveniently small spring working range by over 60% compared to an equivalent rectangular blade.

Design, analysis and optimization of a composite leaf spring for light vehicles

Leaf spring is the most widely used suspension system in automobiles which is subjected to various types of stresses and deflection. Generally, steel is used as a material for the leaf spring but steel is having high density due to which its weight is also more. There is a lot of scopes to replace the steel with other material to reduce the total weight of the vehicle. The advancement in plastic-reinforced fibre is useful for decreasing the weight of the component the composite materials are having high strength and low weight as compared to steel. In this proposed work composite material is used in place of conventional steel. The composite material is made up of glass and fibre called Epoxy resin. Various test is performed to carry out the properties of the composite material. Ant colony optimization approach is used to design and optimization of composite leaf springs. A geometric model of the leaf spring is prepared in the CATIA V5 software and analysis is done. It is found that composite springs can sustain the load the same as that of the steel leaf spring, and less deflection is observed in composite springs than in steel leaf springs. The density of the composite material is low so eventually, weight is also reduced by 70 % to 80%.

Microscopic springs: Investigating viscoelastic and elastic tendencies of the cell membrane.

Cell membranes are normally thought of as viscoelastic materials because they exhibit both viscous and elastic properties when deforming, however, some researchers describe membranes as elastic only. Our project seeks to quantify the membrane deformations during a splitting event, and mathematically predict membrane tensions if it were an elastic or viscoelastic material. Knowing the mechanical description that is most appropriate can help future research interested in describing cell mechanics when cells split, change shape, or move. First, we quantified cell shape from experimental fluorescently dyed membranes using ImageJ. We assume that knowing the physical location of the cell membrane over time can be used to quantify how the cell membrane changes due to forces acting on/in the membrane. We built MATLAB functions to import coordinates from ImageJ, center them, segment them based on arctan values into specific angle quadrants, and calculate the force the membrane experiences based on its location relative to its angular quadrant when considered an elastic spring or viscoelastic material. Centering the coordinates allows the functions to apply to multiple different cell experiments, while quadrants allowed the accounting of localized growth and shrinkage of the membrane. To model the elastic properties, we used a Hooke's Law spring equation and a viscoelastic equation with elastic and damper components. Our results suggest that the cell membrane can be treated as a viscoelastic material under small time scales (< 3 minutes) and as an elastic spring for larger time scale deformations. These results can be validated experimentally through laser ablation. By ablating a hole in the cell membrane, we can quantify the recoil of the membrane to determine how much tension was present before the ablation and compare the scale of the experimental tension with our model predicted tension.

Влияние фунгицидных протравителей на выход товарной продукции и морфобиометрические показатели тюльпанов при ранневесенней выгонке

Tulips are traditionally estimated as the freshest flowers during the spring holidays. At the same time, the imported planting material for early spring sprouting is 100% (or close to this value). Affection by mycosis of imported planting material remains a topical issue. Depending on degree of damage it affects the yield of commercial output and its quality. Studies conducted in the phytotron, an enclosed research greenhouse, carried out by the Department of Remote Hybridization of the Tsytsin Main Botanical Garden of Russian Academy of Science (GBS RAS) including two most popular varieties of tulips have showed that the planting material from Netherlands has a prevalence of mycoses from 47,5 to 99,5%.Preplant treatment by fungicide protectant has affected the acceleration of the onset of the phase of the full color phase of buds for 3-5 days and has a mixed impact on plant height and glass length. The treatment of bulbs with Lamador, (SC, suspension concentrates) had a retardant effect. On the Presto variety, the height of commercial products was 2.7cm lower than the control variant, on the Dynasty variety by 1.2 cm. The treatment of bulbs with the Maxim (SC, suspension concentrates) had the opposite effect. The cutting height was higher than in the control version. At the same time, treatment with fungicidal protectants did not reduce the development of mycoses on tulip bulbs. Keywords: TULIPS, EARLY SPRING GROWING, PLANT PROTECTION, PROTECTANT, FUNGICIDE TREATMENT, BULBS

Weight optimization and finite element analysis of automobile leaf spring: A design construction referred to electric vehicle

In the current era, an automobile vehicle company’s major focus is now on conserving natural resources, reducing consumption of fuel, and reducing the weight of vehicle components. To reduce greenhouse gas emissions and fuel consumption and mitigate global warming, an electric vehicle will be a viable option. However, the EV’s main issue is the vehicle’s battery longevity. More power is necessary to drive a vehicle. The best solution to the issue is to reduce the vehicle component weight. Electric Vehicle suspension systems are another sector in which these developments are performed on a regular basis. Substantial steps are being taken to improve the vehicle ride quality. In this study, static and dynamic analysis has been carried out by finite element analysis at Ansys workbench and taken structural steel material for mono leaf spring. In composite material, carbon fiber and glass fiber have been considered as reinforcement and resin epoxy has been taken as matrix for mono leaf spring. The composite material fabrication has been accomplished layer by layer at Ansys ACP. After analysis, this study has revealed that by using composite material a magnificent amount of weight reduction has been achieved without sacrificing load-bearing capability, strength, and rigidity.