Spring Material Research Articles

Excogitating Material Rankings Using Novel Aggregation Multiplicative Rule (AMR): A Case for Material Selection Problems

Leaf spring is a suspension device that is used to safeguard the vehicle as well as its occupants from the road shocks. The vibrations arising out due to road irregularities must be absorbed by the leaf spring. The potential energy stored as strain energy must be released slowly by the spring. There is a number of materials of construction for leaf spring and to ensure satisfactory performance these materials must have a suitable combination of properties. The material must possess higher mechanical strength, impact toughness, percentage elongation. Furthermore, lower density and Young’s modulus are other important requirements. The material selection of automobile leaf spring is important and should satisfy the aforementioned requirements. A number of decision-making tools have been employed by the decision-makers to address the material selection problem. The present work proposes a novel aggregation multiplicative rule, taking into account the compromising attitude to rank the material alternatives for automobile leaf spring. Epoxy composite reinforced with E-glass fiber was revealed to be the most suitable material for the automobile leaf spring. The validity of the results obtained using the proposed algorithm has been done using sensitivity analysis as well as through applicability to already solved material selection problems. The performance analysis of the proposed algorithm has been compared with other popular multi-criteria decision making tools: technique for order of preference by similarity to ideal solution, evaluation based on distance from average solution, VlseKriterijumska Optimizacija I Kompromisno Resenje, COmbinative Distance-based ASsessment, Tomada de Decision Inerativa Multicritero, Preference Ranking Organization METHod for Enrichment and multi-objective optimization on the basis of ratio analysis through Spearman’s rank correlation. The algorithm is found to have robustness, reliability and unique structure and can be used in the automotive industry to assist in the material selection process.

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.

Using Environmental DNA to Monitor the Spatial Distribution of the California Tiger Salamander

AbstractGlobal efforts to conserve declining amphibian populations have necessitated the development of rapid, reliable, and targeted survey methods. Environmental DNA surveys offer alternative or complementary methods to traditional amphibian survey techniques. The California tiger salamander Ambystoma californiense (CTS) is endemic to California, where it breeds in vernal pools. In the past 25 y, CTS has faced a 21% loss of known occurrences, largely through habitat loss, and it is threatened by hybridization with an introduced congener. Protecting and managing remaining CTS populations rely on accurately monitoring changes in their spatial distribution. Current monitoring practices typically use dip-net surveys that are time-consuming and prone to false negative errors. To provide a new resource for monitoring and surveying larval CTS, we designed an assay and tested it on water samples collected from 29 vernal pools at two locations in California. We compared environmental DNA results to contemporaneous dip-net surveying results and found the assay agreed with positive dip-net results in 100% of cases. In several instances, we also detected the presence of CTS genetic material in the early spring before larvae hatched, potentially offering a new, earlier detection option for this imperiled species. This assay provides a valuable, noninvasive molecular tool for monitoring the spatial distribution of the CTS in vernal pools.

English

In modern trends of the automobile industry, the ride comfort for drivers is the safety and suspension performance of a vehicle. In vehicles, vibration is one-factor causing damages to the base of the vehicle, wear and tear, etc. Vibration control is a major factor to satisfy customers. In this study, the suspension system in the vehicle is the main component to control the vibration. From the concept of suspension system in a vehicle, there are different approaches in the suspension system such as to modified design in suspension, the alternate system instead of the conventional method, Material changing, etc. In this work from suspension system, spring is playing an important component which withstands the load and cause for vibration. Analytical work is carried out with changing the material properties of the spring resulted that vibration has reduced in composite material. The existing material in suspension spring is steel alloy which withstands vibration to a certain limit beyond that it gets failed and breaks. To overcome such a problem in this work we propose new material based on MMC (Carbon Steel 50%, Copper 25%, and Magnesium 25%). By validating the analytical result in structurally by deformation, equivalent stress, and dynamically observed vibration, etc. Finally, the Comparative analysis has derived and concluded for the feasible material in spring manufacturing. Modeling work is done with SOLIDWORKS Software and analysis is carried out with ANSYS software which is best for FEM.

Failure analysis of a motor vehicle suspension helical spring

The purpose of this work is to reveal the cause of the failure of the motor vehicle rear suspension barrel-shaped spring with the progressive elasticity characteristic and predict measures to increase the lifetime of springs of this type. The fracture of the spring occurred on the middle coil, which operates under conditions of more severe stress in comparison with other coils. The chemical composition of the spring material, determined by X-ray fluorescence spectral and microstructural analyzes, corresponded to chromium-silicon steel 54SiCr6. In terms of structure and mechanical properties, the spring material met the standards. No traces of decarburization were detected, and no crack initiation, caused by non-metallic inclusions, was found in the material of the fractured spring. Macroscopic examination of the spring surface did not reveal any cracks, scratches, dents, traces of blows with stones and marks of spring coiling tool. Instead, extensive areas of exfoliation of the protective coating were found. The metallographic analysis revealed selective corrosion in the form of pitting damage in places of exfoliation of the protective coating. The fatigue crack propagates from the certain deep pit with the reorientation of the crack plane along the spiral surface to the central axis of the coil wire. After depletion of the safety margin, the spring broke down quickly. The fast fracture zone contains steps of the river pattern formed due to the spiral reorientation of the fracture surface. The research can be used to understand the importance of adhesive strength and wear resistance of protective coatings on the spring surface. Their local exfoliation causes subsequent corrosion damage to the spring, which stimulates its fatigue fracture.

Determination of Wear, Friction Behavior and Characterization of Carbon Fiber Reinforced Epoxy Composites for Transport Applications

Abstract Thermoplastics are finding the place in the current industrial sector due to its load bearing capacities. In this research, With the aid of pin on disc test set up, adhesive and abrasive wear behavior of leaf spring materials 30% short carbon fiber reinforced epoxy (SF), 30% long carbon fiber reinforced epoxy (LF) as well as Unreinforced epoxy (UF) are evaluated for automobile applications. Under multi pass abrasive wear condition, the effect of fiber reinforcement on plastic energy of deformation, matrix crystallinity and clogging behavior were investigated. The transient friction of Leaf spring materials was carried out under the load condition of 19.62N and 28.43N. During the friction test, the effect of fiber length, fiber loading condition on the co-efficient of friction and its specific wear rate of the composite materials are also investigated. The increase in load during adhesive mode for all the materials, specific wear rate and wear volume of the test materials also increased. Furthermore, the fiber- matrix interface, fractured surfaces were observed thoroughly through Scanning Electron microscopic (SEM) morphology.

Analysis and optimization of mono parabolic leaf spring material using ANSYS

This research paper describes the work carried out on a mono parabolic leaf spring of a mini loader truck (Tata Ace) with a GVW (gross vehicle weight) of 1550 kg. A leaf spring is simple form of spring, pervasively used for the suspension in automotives. In this paper analysis is done for leaf spring whose thickness varies from the centre to outer end in parabolic nature followed by mathematical equation of a parabola, hence it is named as parabolic leaf spring (PLS). The modeling and analysis of the leaf spring has done in CATIA V5 R20 and ANSYS 15. The finite element analysis of the leaf spring has been carried out by initially discretising the model and then applying the relevant boundary conditions under the static loading conditions. The results from FEA indicated that the red area close to shackle was undergoing maximum value of stress which may lead to failure of mono parabolic leaf spring. A comparison between the different materials of leaf spring has also been performed to study the influence of mechanical properties of different material of PLS, in order to find out the amount of maximum stress for different material. During the analysis of all the materials boundary condition and applied load are same.

Finite element analysis of hybrid composite material based leaf spring at various load conditions

Lot of effort is made to reduce the fuel consumption by automobile vehicles and this can be achieved by reducing the mass of the automobile vehicles. Leaf spring widely used in all types of vehicles including electric vehicles is one such component which could be attempted. Three different materials namely conventional steel, glass epoxy composite and hybrid composite (combination of both steel and glass epoxy) are considered for the leaf spring. FEA analysis is performed using ANSYS finite element code. Von-Misses stresses, deformation, principal stresses and strain are the main parameters that are considered in this study for different loading conditions. The mass of hybrid composite material is 34% lesser compared to conventional steel. Maximum principal stresses of hybrid composite material are 60% lesser than steel. The mass of hybrid composite material is 34% lesser compared to conventional steel. Finally, the hybrid composite material can be used as a leaf spring material thereby reducing the overall weight of the automobile vehicles.

Textile structural composites for automotive leaf spring application

This work dealt with the textile structural reinforced composites (TSRC) prepared by different textile structures as reinforcement in epoxy by employing vacuum assisted resin infusion molding (VARIM) process. The textile structures were used in form E−glass uni-directional (UD) tow, bi-directional (2D) plain woven fabric and 3D woven orthogonal fabric. Chopped fibers reinforced composite were also prepared to compare their performance with TSRC. All composite structures were prepared with similar volume fraction and identical processing condition. In this context influence of reinforcement architecture on the static and dynamic mechanical performance of composites were investigated for their applicability in automotive leaf spring compared to conventional steel. TSRC were analyzed for mechanical properties like tensile strength, flexural strength (3 point bending), Izod impact strength. Further damping and wear behavior were also investigated to know their applicability as leaf spring material. Mechanical performance of 3D woven based composite leaf spring were found significantly better than chopped, UD and 2D counterparts with regard to delamination, impact strength and improved storage modulus. Overall 3D composite leaf spring showed high potential for automotive leaf spring applications.

Finite element analysis of the SiC/SiC composite clad deformation in the presence of spacer grids

The deformation of a two-layer SiC clad in the context of pressurized water reactor fuel assembly has been analyzed in the present work. Firstly, azimuthal temperature difference that can lead to clad bowing has been estimated using a plane strain model in BISON. Then a 3D finite element analysis model has been set up in ABAQUS to investigate a full-length clad bowing as well as its mechanical interaction with multiple spacer grids (SGs). The analysis assumes metal (Zircaloy or Inconel 718) as the SG spring material to accommodate SiC clad deformation. The prediction of the mechanical response for the simplified grid-to-rod system due to grid spring pre-load, SiC swelling, clad bowing and grid spring creep has been performed. The results indicate that the considered SGs will play an important role in limiting the fuel rod bowing for SiC/SiC composite clad during normal operation.

Material properties analysis on spring and screw of an elevator brake

The material properties of spring and screw of an elevator brake failed during use was analyzed. The macroscopic morphology and metallographic microstructure of the spring and screw of an elevator brake were investigated based on the optical microscope and scanning electron microscope analysis. The chemical composition was analyzed by X-ray energy spectrum analysis. The results showed that the material of spring and screw are 65Mn spring steel and 40 steel, respectively. The material of spring has porous holes inside.

Hydraulic Conductivity of Sandy Soil with Varying Grain Size

A concept of mean particle size and size factor is presented in this paper and an attempt is made to relate the hydraulic conductivity to mean particle size, taking into account the optimum moisture content and maximum dry density. The distribution of particle size has a significant effect on hydraulic conductivity. It is possible to determine the mean particle size and size factor from the gradation curve. For the purpose of experimental analysis, three samples of soils were collected, local river sand available in market, coarse sand1.18mm sieve and quarry dust. For determining the hydraulic conductivity a constant head permeability test is conducted. A few exact conditions to compute water powered conductivity utilizing grain estimate dispersion of unconsolidated spring materials have been assessed in this examination. Evaluating examination of soil tests extricated from the test openings during ground water examination venture was performed to decide their arrangement and molecule measure dispersion attributes, from which pressure driven conductivities were figured. In particular, every single exact equation are to be utilized carefully inside the space of appropriateness

Cereal pests among nest parasites – the story of barley thrips, <i>Limothrips denticornis</i> Haliday (Thysanoptera: Thripidae)

Barley thrips, Limothrips denticornis, Haliday, 1836 (Thysanoptera: Thripidae), a grass-dwelling Holarctic species represents a model example to study transport mechanisms of Thysanoptera into nests. In samples from more than 1,500 nests, barley thrips were recorded in nests of 20 vertebrate species, both birds and mammals. Applying appropriate statistics (nonparametric methods) clear clustering among nest materials and a strong relationship between presence of thrips and grass as the nest material was found. Occurrence of thrips was not associated with nest size, location or height. To validate our statistical analyses 15 wooden boxes were installed and equipped with sticky traps to record the whole year migration dynamics. Barley thrips infiltrate nests by various ways (e. g. dwelling on bark, landing from atmosphere), however most of them (88%) invade passively on nest material (grass) in spring (1st summer nesting) and autumn (winter nest building).

Design, Analysis and Experimental Testing of Composite Leaf Spring for Application in Electric Vehicle

In electric vehicle segment it is significantly observed that the excess weight of batteries (>10% of overall weight) reduces the travel range of electric vehicle. This excess weight of the batteries causes higher compression of the springs & also reduce the space available for suspension travel which reduces the life of suspension & comfort to the passenger. To overcome these issues, suspension needs to be reconfigured in terms of geometry & material of the suspension. Considering above changes in suspension system, Leaf Spring can be considered due to its proven history. Leaf spring has high load bearing capacity & can handle high loads at less deflection resulting in smoother ride. In this study glass fiber is used to analyze the application of leaf spring for excess weight in electric vehicle. The main objective of this study is to investigate feasibility of composite material for leaf spring to withstand the excess load in Electric vehicle. Rear leaf spring of TATA Sumo passenger vehicle is considered as case study model, which is semi-elliptical laminated type. The CAD model was created in CATIA & imported to ANSYS. Analytical, Experimental and Finite Element Analysis were carried out on composite prototype. Weight optimization of 67.70% for GFRP is observed in comparison to EN 46 material. For deflection 3.93%, for stiffness 4.06%, for energy absorbed 3.94% and for natural frequency is 5.25% difference is observed.

Manufacture and Testing of Air Springs Used in Railway Vehicles

In this study, the mechanical properties of the air spring used in secondary suspension systems in railway vehicles have been experimentally determined. Firstly, rubber recipes with different components were determined for the production of rubber material, the main raw material of the air spring. Afterward, the mechanical properties of the elastomer material to be used in the manufacture of the air spring were determined by uniaxial tensile tests and RPA (rubber process analyzer) tests were applied to the samples obtained from different types of rubber compound. The machines used for the production of air spring and the test machines used for determining the mechanical properties of the air springs were specially produced and commissioned within the scope of the study. Blasting, airtightness, lifting–expansion, vertical spring coefficient, horizontal spring coefficient and lifetime tests were carried out by using these test machines.

Study of leaf spring fracture behavior used in the suspension systems in the diesel truck vehicles

The leaf spring is frequently applied on a vehicle such as used on the truck and it is one of the machine element suspension systems. It needs to have an excellent resistance to the fracture propagation to avoid failure that could lead to severe accidents. Fracture failure on the leaf spring is frequently experienced especially on diesel trucks, known as premature failure. Therefore, this case is needed to be studied and investigated. The purpose of this study is to investigate the cause of failure on the broken leaf spring by counting analytically the stress intensity factor (KI) occurred near the crack tip. Moreover fracture surface observation conducted by Scanning Electron Microscope (SEM) to find out whether there is or not an initial crack and crack propagation direction. This present study describes the experimental work and analytical analysis of theleaf spring used on Diesel Truck Vehicle. Hardness testing was performed using the Rockwell method. The chemical composition testing on the leaf spring material was found that the material in accordance with AISI 5150 standard. The hardness value of leaf springs tested of about 106.9 HRB. The result of analytical analysis shows that the maximum value of stress intensity factor (KI) occurred near the crack tip at the near the hole of leaf spring. In this case the value of KIis higher than thevalue of the fracture toughness (KIC) of the leaf spring material. Therefore, this result could be inferred that crack propagation happened starting from initial crack tip which is located near the hole on the leaf spring. The failure of leaf springs also caused by fatigue crack propagation due to dynamic loading during the operation marked by appearance the beach mark on the fracture surface.

Taxonomy, ecology, and distribution of the genus Rhododendron (Ericaceae) in South Carolina

Data from field trips and a survey of herbarium specimens was used to determine relative abundance of the ten known species of Rhododendron (Ericaceae) in each county of South Carolina. All counties were documented to contain at least one species. The western-most mountainous and upper piedmont counties of Oconee, Pickens, Spartanburg, and Greenville were found to have the greatest richness and the greatest number of documented populations. Of the four counties with only one documented species, three are in the piedmont and one in the coastal plain. Species found in the greatest number of counties were Rhododendron canescens. R. viscosum, and R. periclymenoides. Meanwhile species known from the fewest number of counties were R. calendulaceum. R. flammeum. R. maximum, and R. arborescens. Taxonomic keys were generated for species identification, the first key for spring and early summer flowering material, and the second for summer and fall vegetative or fruiting material.

Investigation of Forced Frequency in a Commercial Vehicle Suspension System

Abstract Vehicle suspension plays a vital role in maintaining the center of gravity to achieve perfect balancing of the vehicle to provide the comfortable ride. While designing the suspension system of automobile, vibration is the main aspect to be considered. This paper aims to analyze the automobile front and rear suspension for a four wheeler using analytical and numerical approach. Existing details of the suspension is collected using the concept of reverse engineering. Natural and forced frequency of the front and rear suspension system is calculated theoretically based on the collected data's. The natural frequency and forced frequency is numerically computed for front and rear suspension. The amplitude of vibration is reduced by replacing the spring material and its forced frequency is reduced by 1.18 % and 1.56 % for front and rear suspension system respectively. This result reveals that low carbon steel has ability to reduce the forcing frequency and can produce comfort ride.

Synthesis of a Helical Analogue of Kekulene: A Flexible π-Expanded Helicene with Large Helical Diameter Acting as a Soft Molecular Spring.

A π-expanded helicene that is the helically twisted analogue of kekulene was synthesized using a 6-fold ring-closing olefin metathesis (RCM) reaction as a key step. The π-expanded geometry with large helical diameter ( dh = 10.2 Å), consisting only of carbon and hydrogen atoms (C54H30), was unambiguously determined by single-crystal X-ray analysis. We found that the π-expanded helicene with large helical diameter will act as a soft molecular spring with a small spring constant. Interestingly, the mechanical properties of the molecular springs roughly satisfied a physical formula for macroscopic spring materials; i.e., the force constant of the elongation of a molecular spring ( k) is inversely proportional to the third power of the helical diameter ( k ∝ dh-3).

Stress, Deformation and Failure Analysis of Parabolic Leaf Spring by Finite Element Analysis with Material Optimization

A leaf spring is a simple form of spring commonly used for the suspension system in heavy duty vehicles which is originally called laminated or carriage spring. It performs the isolation task in transferring the vibration due to road irregularities to the passenger’s body or goods transported on it. The advantage of leaf spring over helical spring is that the ends of the spring have been guided along a definite path as it deflect to act as a structural member in addition to an energy absorbing device. Increasing competition and innovations in the automobile sector, tends to modify the existing products with new or advanced material products. To improve the performance of the suspension system, many modifications have been taken place overtime but the recent innovations imply parabolic leaf spring and application of composite materials, as the composite materials have high strength-to-weight ratio compared to the conventional steels. The present work attempts to analyze the comparison between the conventional steel (AISI1030) leaf spring and the composite (Carbon/Epoxy) leaf spring with respect to static and fatigue analysis. Here static analysis determines the safe stress, deformation and corresponding pay load and also studies the behavior of structures under practical conditions. The research also focuses on fatigue analysis to determine its life cycle and also to observe its fatigue failure characteristics. The model of the leaf spring has been carried out into the CAD software. The analysis of the steel leaf spring has been divided into theoretical, experimental and simulation sections. The simulation of steel leaf spring has been validated with the theoretical and the experimental results. Further simulation has been done for composite leaf spring by FEA software. Finally, the result shows that the composite leaf spring has better load carrying capacity in reduced weight, and better fatigue behavior rather than the conventional steel material for the leaf spring.