Conical Spring Research Articles

Application of conical spring to maintain tuning of mass damper for wave-induced vibration control of offshore jacket platform subjected to changes in natural frequency

Offshore jacket platforms are situated in challenging environmental conditions and often experience changes in mass and stiffness, resulting in alteration in its dynamic properties. The tuned mass damper (TMD), known for its effectiveness in vibration control, has been earlier studied for implementation in jacket platforms. However, it is sensitive to tuning and would suffer a performance loss if the structural frequency undergoes modification. This can be overcome by connecting the damper mass to the structure by a conical spring that exhibits multilinear behaviour. This allows the TMD to remain tuned to different values of the structural frequency. In this study, the jacket platform is modelled as a multi-degree-of-freedom (MDOF) system, and the performance of the designed TMD with conical spring (TMD-C) is investigated in both frequency and time domain. Two possible variations in the fundamental period of an example jacket structure are considered and the results of wave-induced vibration control of deck responses achieved by the TMD-C are compared with those by the conventional TMD. Results indicate that despite being a passive device, the TMD-C can maintain the desired tuning to the structural frequency and thereby outperforms the conventional TMD in the reduction of the deck responses.

Analisis Perawatan Heading Machine dengan Metode Reliability Centered Maintenance (RCM)

The heading machine is a critical type of machine used in the production of header tubes. If a failure occurs during the production of header tubes, the product cannot proceed to the next process and must be discarded. However, this machine frequently encounters component failures that require halting the machine for repairs, which is detrimental to the company. This research aims to enhance the machine's reliability by identifying the critical components and scheduling appropriate maintenance based on the heading machine's needs. The research method used is RCM, which includes collecting data on machine downtime and repairs, creating an FMEA table, identifying critical components, calculating TTF and TTR, determining component distribution patterns, establishing parameters, calculating the reliability of critical components, and scheduling maintenance. The research findings identified the critical components as conical spring for orifice and jaw for thread. The calculation of the reliability value using the Weibull distribution equation with scale and shape parameters for the conical spring for orifice components are 1001.78 and 1.12285, respectively. For the jaw for thread component, the scale and shape parameters are 532.083 and 1.33233, respectively, based on values derived from statistical software. As a result, the maintenance schedule should be set when the reliability value of the conical spring for orifice and jaw for thread reaches 0.5 at (t) 720 hours or 30 days, and (t) 390 hours or 17 days, respectively.

Development of a novel rocking connection for tubular steel bridge piers: A proof of concept study

AbstractThis paper introduces a novel pocket‐type dissipative rocking connection for self‐centering tubular steel bridge piers. Unlike typical self‐centering systems, this connection does not utilize post‐tensioned tendons and relies solely on gravity load for re‐centering, but it employs a redundant mechanism to prevent geometrical instability and collapse. The connection consists of several components, including an embedded sleeve component and a ring plate bearing against the column and frictionally connected to the embedded component. During rocking, the ring plate provides two‐level energy dissipation through friction and material yielding. In this connection, any residual drift could be easily recovered by untightening bolts in the frictional connection of the ring plate. A finite element model with contact elements at surface interfaces between different components was developed to simulate the response of the connection under vertical and lateral loading. Finite element analyses and quasi‐static cyclic tests of a quarter‐scale specimen demonstrated that the connection could provide adequate lateral resistance and a flag‐shaped hysteresis response with marginal or recoverable residual displacements. Test results confirmed that the connection can sustain large lateral drifts (up to 7.6%) without structural damage. Test results also indicated that the hysteresis characteristics of the connection are highly influenced by the type and configuration of the washers in the bolt assembly of the frictional connection. The lateral strength and energy dissipation properties of the connection were greatly improved when conical spring washers were added to the bolt assembly.

A novel STM for quality atomic resolution with piezoelectric motor of high compactness and simplicity

Scanning tunneling microscope (STM) is a renowned scientific tool for obtaining high-resolution atomic images of materials. Herein, we present an innovative design of the scanning unit with a compact yet powerful inertial piezoelectric motor inspired by the Spider Drive motor principle. The scanning unit mainly consists of a small 9 mm long piezoelectric tube scanner (PTS), one end of which is coaxially connected to the main sapphire body of the STM. Of particular emphasis in this design is the piezoelectric shaft (PS), constructed from piezoelectric material instead of conventional metallic or zirconium materials. The PS is a rectangular piezoelectric stack composed of two piezoelectric plates, which are elastically clamped on the inner wall of the PTS via a spring strip. The PTS and PS expand and contract independently with each other to improve the inertial force and reduce the threshold voltage. To ensure the stability of the PS and balance the stepping performance of the inertial motor, a counterweight, and a matching conical spring are fixed at the tail of the PS. This innovative design allows for the assessment of scanning unit performance by applying a driving signal, threshold voltage is 50 V at room temperature. Step sizes vary from 0.1 to 1 µm by changing the driving signal at room temperature. Furthermore, we successfully obtained atomic-resolution images of a highly oriented pyrolytic graphite (HOPG) sample and low drift rates of 23.4 pm/min and 34.6 pm/min in X-Y plane and Z direction, respectively, under ambient conditions. This small, compact STM unit has the potential for the development of a rotatable STM for use in cryogen-free magnets, and superconducting magnets.

Effectiveness of displacement compensation units for integral abutment bridges

Integral abutment bridges (IAB) have become increasingly popular in the past few decades due to their design simplicity. UK design rules limit the length of IABs to 60 m, due to the issues associated with thermal strains, settlement, and pressure build-up behind the abutment. A cyclic loading test, representing seasonal thermal fluctuations, was conducted on a 1/12 scaled-down retaining wall of a conventional full-height IAB. The test was then repeated with the inclusion of displacement compensation units (DCU) in the form of conical disc springs (CDS) and hollow rubber cylinders (HRC), which operate in a pre-deformed shape. The results show some remarkable improvements in the IAB performance with DCUs. The soil backfill pressure was reduced to 30% and 47% with CDSs and HRCs, respectively. Furthermore, no settlement was observed, as compared to the conventional IAB test which recorded a 20 mm settlement after 100 cycles. Non-linearity in the force-deflection behaviour of DCUs enables expansion and contraction of the deck to be accommodated with minimal fluctuation of backfill pressure. Finally, a finite element (FE) model of an HRC applied with two temperatures has been analysed and compared with the IAB wall test, which suggests that both analyses showed some correlation.

Bio-inspired design of shock absorber for electronic board of satellite

In nature, various mechanisms help living organisms to survive. These mechanisms have been optimized over time in nature. Taking inspiration from these mechanisms in different industries can help solve problems. In this article, the chameleon tongue structure is used to reduce the shock on the electronic board of the satellite. To reduce the shock on the electronic board in the satellite, which is subjected to shock during launch and separation, a spring leg has been designed. To increase the range of frequency, in which the acceleration of the board is lower than the input acceleration, and also to improve this structure, conical springs were also investigated for the satellite board system. Various factors affecting shock transmission on the electronic board were investigated. The results show that at low frequencies (high shock duration), independent of the spring structure, the acceleration of the board is equal to the input acceleration. The results show that the designed spring legs reduce the amount of shock on the electronic board compared to the rod leg.

Experimental Investigation of Conical Spring Inserts on In-Tube Heat Transfer and Pressure Drop

Experimental Investigation of Conical Spring Inserts on In-Tube Heat Transfer and Pressure Drop

MODELING OF A CONTROLLED ELECTROMAGNETIC VIBRATION DRIVE WITH A VARIABLE RESONANT FREQUENCY

The technology for the production of high-quality concrete products includes the vibration of the concrete mixture at various frequencies. For this, an electromagnetic vibration drive can be used, which has high reliability, durability and controllability. For its effective application, it is necessary to adjust the resonance frequency of the oscillating system in order to ensure the near-resonance mode of operation at different frequencies. This is possible by using devices with adjustable stiffness, in particular, controlled dynamic vibration absorbers with nonlinear elastic elements. In the article the electromagnetic, electromechanical, mechanical, and energy processes in a controlled vibration system, which includes an electromagnetic vibrator and a vibration absorber with conical springs, the stiffness of which is regulated by compression using a press, have been investigated. Using the circle-field method, a mathematical and simulation model of electromagnetic and electromechanical processes in the vibrator has been developed. For this purpose, numerical calculations of the magnetic field in the vibrator have been performed and, based on the obtained results, the functional dependences between the electromagnetic force, magnetic flux, magnetomotive force and the size of the air gap have been determined. A model of the mechanics of the oscillating system, processes in the vibration absorber press drive and processes in the control system has been also developed. The built simulation models were combined into a general model in the Simulink environment, by means of which the time diagrams of the processes have been obtained. The modeling results show that the system provides a smooth transition from one vibration frequency to another while maintaining the specified amplitude of the working body oscillations and near-resonance mode with high energy efficiency. References 12, figures 10, tables 3.

Exact shell solutions for conical springs. III. Belleville springs with variable thickness

PurposeIn the current manuscript, the authors examine the Belleville spring with the variable thickness. The thickness is assumed to be variable along the meridional and parallel coordinates of conical coordinate system. The calculation of the Belleville springs includes the cases of the free gliding edges and the edges on cylindric curbs, which constrain the radial movement. The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations.Design/methodology/approachIn the current manuscript, the authors examine the Belleville spring with the variable thickness. The calculation of the Belleville springs investigates the free gliding edges and the edges on cylindric curbs with the constrained radial movement. The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations.FindingsThe developed equations demonstrate that the shift of the inversion point to the inside edge does not influence the bending of the cone. On the contrary, the character of the extensional deformation (circumferential strain) of the middle surface alternates significantly. The extension of the middle surface of free gliding spring occurs outside the inversion. The middle surface of the free gliding spring squeezes inside the inversion point. Contrarily, the complete middle surface of the disk spring on the cylindric curb extends. This behavior influences considerably the function of the spring.Research limitations/implicationsA slotted disk spring consists of two segments: a disk segment and a number of lever arm segments. Currently, the calculation of slotted disk spring is based on the SAE formula (SAE, 1996). This formula is limited to a straight slotted disk spring with freely gliding inner and outer edges.Practical implicationsThe equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations. The developed method is applicable for disk springs with radially constrained edges. The vertical displacements of a disk spring result from an axial load uniformly distributed on inner and outer edges. The method could be directly applied for calculation of slotted disk springs.Originality/valueThe nonlinear governing equations for the of Belleville spring centres were derived. The equations describe the deformation and stresses of thin and moderately thick washers. The variation method is applicable for the disc springs with free gliding and rigidly constrained edges. The developed method is applicable for Belleville spring with radially constrained edges. The vertical displacements of a disc spring result from an axial load uniformly distributed on inner and outer edges.

横轴流玉米柔性脱粒元件的设计与试验

In order to solve the problem of high broken rate and impurity rate in the direct harvesting of corn kernels in China, a flexible threshing element with variable stiffness consisting of a conical spring and rasp bar was developed on the basis of the existing horizontal axial-flow flow corn threshing cylinder structure to achieve low loss harvesting of corn kernels. Through mechanical analysis of the key components of the threshing element, its structure and operating parameters were determined. Then, orthogonal tests were carried out using the feed amount, threshing clearance and cylinder speed as the test factors, and the broken rate and impurity rate of the corn kernels as the test indicators. The results showed that the feed amount, threshing clearance and cylinder speed had a significant effect on the broken rate and impurity rate of corn kernels; the optimum parameters for the corn variable stiffness flexible threshing device were feed amount 6.1 kg•s−1, threshing clearance 40 mm and cylinder speed 392 r•min−1. The broken rate of corn kernels was 1.67% and impurity rate 1.03%. The test results fully met the requirements of the national standards for corn harvesting operations. This study provides a technical basis for the application of the axial flow corn flexible threshing device in the corn direct harvesting combine.

GEARBODIES - Innovative Technologies for Inspecting Carbodies and for Development of Running Gear

This work presents the progress of the ongoing Shift2Rail project GEARBODIES. The project has designed an inspection platform for the inspection of composite carbody shell, integrating thermography and ultrasonic equipment. GEARBODIES has also selected the two elastomer-metal components to be prototyped, a bushing in swingarm and a conical spring in primary suspension. Both components will be improved employing carbon nanotubes in the elastomer formulation. The last groups of innovations explored are focused on the journal bearings. To improve roller-race materials, a first selection of four potential High Entropy Alloys candidates have been selected. Regarding lubricants, it has been identified that working on housing solutions are more promising that working on bearing sealing solutions. The first test on polymers for cages have been also performed as well as potential modifications on the geometry of the bearing components. The presented results will be further researched and the conclusions published in future works.

Experimental and CFD analysis of wire coil turbulators in biomass boilers

To achieve as complete fuel burnout with as little excess air as possible, small wood log boilers (< 50 kW) use stage combustion. The first stage is often a process similar to downdraft gasification that consequently produces a flue gas laden with particulates. To prevent the build-up of solids and promote heat transfer in pipes of the convective part of these boilers, wire coils are used. The paper presents their in-situ examination together with CFD analysis. The analysis is carried out in a 460 mm long pipe, with a diameter of 82.5 mm, equipped with different wire coils for flue gas temperatures in the range between 300?C and 150?C. The analyzed coils are with and without a conical spring at their free end. The addition of this conical top is economical and should influence the rotation of the core flow. Proper pipe surface cleaning limited the analyzed wire coil designs to the dimensionless pitch, p/d, in the range between 0.36-0.61, dimensionless wire diameter e/d = 0.04-0.1, and pitch to wire diameter ratios p/e = 3.75-14.3, and three different angles (60?, 90?, and 120?) of the conical top. The goals are to find the optimal flue gas velocity for the given operating conditions, pipe, and wire coil dimensions, and to investigate the addition of the conical top on heat transfer enhancement. Several evaluation criteria are used to achieve the goals.

Experimental studies of the dynamics of the proposed design of the presser foot with an additional conical spring

This article is devoted to light industry equipment, namely sewing machines that are utilized in the manufacture of clothing, footwear and knitwear. The disadvantage of this design is the lack of vibration damping of the trigger and rod caused by changes in the thickness and structure of the sewing material, the impact resistance of iron and the incompatibility of the rotating elements in the sewing machine.

Experimental determination of the law of vibration of the improved jet mechanism of the sewing machine

The article presents the results of experimental determination of the oscillation law of the proposed additional conical spring mechanism of the effective reaction. The results of calculation of compressive strength and spring elasticity are presented. The change in the force acting on the reaction is determined by the electrostrain method and is based on its parameters.

Effect of nonlinear conical springs on the vibration characteristics of seven degree-of-freedom car model using MATLAB/Simscape

Effect of nonlinear conical springs on the vibration characteristics of seven degree-of-freedom car model using MATLAB/Simscape

Permanent-Magnetically Amplified Brake Mechanism Compensated and Stroke-Shortened by a Multistage Nonlinear Spring

Electromagnetic (EM) brakes are widely used but consume electricity continuously to maintain their activated state. In this letter, for efficient braking and idling of robots and vehicles, we proposed a concept of a brake mechanism using a permanent magnet for the amplification of the pressing force between brake pads, allowing for the brake torque to be steplessly regulated by a minimal external force. The prototype of the proposed mechanism was developed with a newly devised compensation spring—not the conventional conical coil springs—comprising two linear springs to shorten the pad-detaching stroke. For proof of concept, evaluation experiments based on the Japanese Industrial Standards were conducted. Both the maximum static and average dynamic friction torques increased to 161.0% and 192.9%, respectively, when identical pads of an EM brake were used for comparison. Power saving was also achieved when braking for longer than 0.43 s; the torque–energy efficiency increased by 8.7 when measured for 1.0 s, successfully revealing the effectiveness of the proposed principle. Further, based on the force–displacement characteristic of the compensated magnet, the theoretical response time was numerically analyzed as 13.6 ms—comparable to the contrasted EM brake—validating the actual behavior of 14.0 ms.

The mathematical model for lateral stiffness of variable length conical spring

Abstract One form of energy storage in spring is applying a bending moment and converting it into tilt at the head of the spring as strain energy. The relationship between them is the lateral stiffness of the spring. The aim is to find a mathematical equation for the lateral stiffness of the spring and the effect of the length of the spring on the behavior of stiffness. The mathematical model is created according to Castigliano’s second theorem. A simulated model of a conical spring is built using a Solid Work program. The theoretical results are compared with the mathematical model for the same conical spring. Results of both theoretical and simulated models evinced a linear behavior of lateral, while an exponential relationship between the length of the spring and the lateral stiffness is indicated. The difference between theoretical and simulated models is not exceeded 3.2%, which indicates the acceptability of results.

Manufacturing and Calibration of Conical Springs Lateral Stiffness Meter

The spring is an important mechanical part of which widely used in many industrial applications. There is an urgent need to know its stiffness property before use in any application. Since the stiffness varies according to the method of using the spring in this research, it is suggested to calculate the lateral stiffness of spring by the moment effect. the device meter of the lateral stiffness of conical springs has been designed and manufactured working principle applying a torque to the head of the spring and calculating the angle of inclination. This research includes an experimental aspect (tensile test of steel wires, manufacture of the device lateral hardness meter, manufacture of four conical springs from steel wire inspected with diameters of 3.4, 3.8, 4, and 5 mm, and testing the springs with the manufactured device). As for the simulation aspect, it comprises calculating the lateral stiffness by numerical analysis using the solid work program. After extracting the hardness values practically by the device and comparing them with simulation values, the device proved its efficiency for small diameters after the experimental results have been compared with the results of the simulation, as the error rate increased with the increase in the diameter of the spring wire, so the highest acceptable error that could be reached by the device was 5% for the diameter 4.36 mm and zero error at the diameter 1.2 mm.

Critical Frequency of Self-Heating in a Superelastic Ni-Ti Belleville Spring: Experimental Characterization and Numerical Simulation.

The mechanical loading frequency affects the functional properties of shape memory alloys (SMA). Thus, it is crucial to study its effect for the successful use of these materials in dynamic applications. Based on the superelastic cyclic behavior, this work presents an experimental methodology for the determination of the critical frequency of the self-heating of a NiTi Belleville conical spring. For this, cyclic compressive tests were carried out using a universal testing machine with loading frequencies ranging from 0.5 Hz to 10 Hz. The temperature variation during the cyclic tests was monitored using a micro thermocouple glued to the NiTi Belleville spring. Numerical simulations of the spring under quasi-static loadings were performed to assist the analysis. From the experimental methodology applied to the Belleville spring, a self-heating frequency of 1.7 Hz was identified. The self-heating is caused by the latent heat accumulation generated by successive cycles of stress-induced phase transformation in the material. At 2.0 Hz, an increase of 1.2 °C in the average temperature of the SMA device was verified between 1st and 128th superelastic cycles. At 10 Hz, the average temperature increase reached 7.9 °C and caused a 10% increase in the stiffness and 25% decrease in the viscous damping factor. Finally, predicted results of the force as a function of the loading frequency were obtained.

Conical Spring Inserts Effect on the Thermo- hydraulic Characteristics in Circular Copper Tube

Experimental and numerical investigation was conducted to study the thermo-hydraulic characteristics in circular tube fitted with conical spring inserts. The dimensions of circular copper tube are 100cm, 2.2cm and 2.4 cm which represent the length, inner and outer diameters respectively. The length of insert was 15cm, while the conical spring has 16mm diameter gradually decreases to 6mm with the length and the pitch between the coils was 20mm. The diameter of wire used to fabricate the conical spring insert was 4mm. Those inserts were arranged into eight categories (A1 to A8). In the numerical part, the governing equations were solved by using commercial ANSYS-Fluent package (2019 R3) with the assistance of solid works and Gambit software program. The finite volume approach was used in solving the equations to predict the pressure flow, heat transfer and temperature distribution along the tube. Experimental work included design and built a test platform for the experimental measurements. The aim of experimental study was to predict the behavior of heat transfer and pressure in the tube with two cases, plain tube and inserted tube at the effect of different parameters. All experimental tests were conducted at turbulent flow fully developed. The range of Reynolds number and heat flux were (3542-7522) (4549-10576 W/m^2) respectively. The results showed that the best augmentation in heat transfer was by using a category A5 of conical spring insert compared with plain tube. Results show good agreement between the numerical and experimental results with an error of 8%. Also results showed that the Nusselt number increases as the Reynolds number increasing.