Rubber Spring Research Articles

Experimental Verification of Vibration Reduction of the Steel Platform for Two Limestone Sorters

The article deals with damping design for steel platform with sorters for limestone. The steel platform has very small damping for two vibration sorters. The sorters are situated in the third floor of old reinforced concrete frame building. The sorters (Fig. 1) are supported by rubber springs (Fig. 2), bud the rest energy from vibration of sorters excite the supporting platform. The response of the platform is unacceptable for both service people and for technology. Therefore vibration absorber for minimization of the response of the steel platform was developed

Testing Equipment Location on Springing Base Plate

When is the hydropulser running, is a source of broad-band vibrations. Removing these unfavourable influences, which act negatively on environment and especially on human beings, is by an elastic support possible. Rubber or air springs are inserted between the frame of the hydropulser and the floor. Under these conditions, the transmission of vibration transferred to the floor declines according to values of natural frequencies. In this paper are discussed two possibilities of base plate (base) support. Especially using of air springs shows high efficiency of vibration insulation springing base

Research of Jiles-Atherton Dynamic Model in Giant Magnetostrictive Actuator

Due to the existence of multicoupled nonlinear factors in the giant magnetostrictive actuator (GMA), building precise mathematical model is highly important to study GMA’s characteristics and control strategies. Minor hysteresis loops near the bias magnetic field would be often applied because of its relatively good linearity. Load, friction, and disc spring stiffness seriously affect the output characteristics of the GMA in high frequency. Therefore, the current-displacement dynamic minor loops mathematical model coupling of electric-magnetic-machine is established according to Jiles-Atherton (J-A) dynamic model of hysteresis material, GMA structural dynamic equation, Ampere loop circuit law, and nonlinear piezomagnetic equation and demonstrates its correctness and effectiveness in the experiments. Finally, some laws are achieved between key structural parameters and output characteristics of GMA, which provides important theoretical foundation for structural design.

Parameter Identification on Lumped Parameters of the Hydraulic Engine Mount Model

Hydraulic Engine Mounts (HEM) are important vibration isolation components with compound structure in the vehicle powertrain mounting system. They have the characteristic that large damping and high dynamic stiffness in the high frequency region, and small damping and low dynamic stiffness in the low frequency region, which can meet the requirements of the vehicle powertrain mounting system better. The method to identify the lumped parameters of the HEM is not only the necessary work for the analysis and calculation in dynamic performance and can also provide the theory for the performance optimization and structure optimization of product in the future. The parameter identification method based on coupled fluid-structure interaction (FSI) and finite element analysis (FEA) was established in this study to identify the equivalent piston area of the rubber spring, the volume stiffness of the upper chamber, as well as the inertia coefficient and damping coefficient of the liquid through the inertia track. The simulated dynamic characteristic curves of the HEM with the parameters identified are in accordance with the measured dynamic characteristic curves well.

Smart damper using the combination of magnetic friction and pre-compressed rubber springs

This paper proposes a new concept of a smart damper using the combination of magnetic friction and rubber springs. The magnet provides energy dissipation, and the rubber springs with precompression contribute to increasing the recentering capacity of the damper. To verify their performance, dynamic tests of magnet frictional dampers and precompressed rubber springs were conducted. For this purpose, hexahedron neodymium (NdFeB) magnets and polyurethane rubber cylinders were used. In the dynamic tests, the loading frequency was varied from 0.1 to 2.0Hz. The magnets showed almost perfect rectangular behavior in the force–deformation curve, and the frictional coefficient of the magnets was estimated through averaging and regression. The rubber springs were tested with and without precompression. The rubber springs showed different loading path from the second cycle and residual deformation that was not recovered immediately. The rubber springs showed greater rigid force with increasing precompression. Finally, this paper discusses the combination of rigid-elastic behavior and friction to generate ‘flag-shaped’ behavior for a smart damper and suggests how to combine magnets and rubber springs to obtain flag-shaped behavior. The performance of the magnets and precompressed rubber springs was verified through analytical models.

Creep simulation and experiment for rubber springs

Rubber creep, as a time-dependent deformation, is one of the critical factors when considering engineering design and applications for anti-vibration structures. A function based on material damage with a variable T (time elapsed) and an invariant [Formula: see text] is introduced to hyperelastic constitutive models based on strain energy density for polymer creep prediction. The concept is to link rubber creep to its structure change, leading to degradation of the materials over the elapsed time. Hence, hyperelastic models, widely available in industry, can be extended to include the variable time T so that a creep evaluation for rubber structures can be performed at a design stage and in the service. A typical rubber-to-metal bonded component, which is used in industrial applications, is selected to validate the proposed approach. Verification shows that the proposed approach predicts nearly identical experimental results, and the method can be used for engineering design and industrial applications.

Vibroisolation of Vibratory Conveyors

Vibratory conveyors are used especially within serial productions for the transport of diverse materials and parts for assembling. The desired oscillating movement is accomplished by electromagnetic exciting forces. The exciting force of this dynamic system actuates between the carrying element and the inertial mass. The inertial mass is fixed to the ground by an elastic constraint using a relatively stiff rubber spring. This elastic constraint ensures the conveyor’s stability and defines its position towards the assembly line, but does not meet relevant effective vibration isolation demands. One possible solution would be a vibratory conveyor air suspension as is being introduced below.

Finite Element Analysis on the Key Parts of Rubber Suspension

Rubber suspension system is a new suspension system in which rubber is used to be the elastic element, thus rubber spring is one of the key components of suspension. Based on its concrete structure, a finite element model of rubber spring is made and so as to analyze the rubber suspension forces under different working conditions, to analyze the strength and stiffness for providing a reference for the design.

Design of Underwater Acoustic Vector Sensor and its Elastic Suspension Element

Acoustic vector sensor is a kind of inertial sensors. Different from pressure-sensing sensor, it can sense the angle of target under the water. Now most suspension elements are installed on the acoustic vector sensor later. This paper outlines an acoustic vector sensor which is encased in silicon rubber. In this paper, a new structure of acoustic vector sensor is present. The radial stiffness of silicon rubber spring is analyzed by using theory and simulation calculation based on the finite element software ANSYS. At last, the acoustic vector sensor is measured. The results show that the new structural design of acoustic vector sensor could reduce the adverse impact of suspending elastic suspension elements repeatedly and improve the reliability of acoustic vector sensor.

스마트 댐퍼구현을 위한 자력마찰 댐퍼 성능실험

이 연구에서는 스마트 댐퍼 구현을 위한 자력마찰과 고무 스프링의 조합을 이용하는 기법에 대해서 제안을 했다. 자석의 에너지소산 능력을 비접촉과 접촉에 의한 기법을 비교하였다. 비접촉은 자기유도반발이고 접촉은 마찰력을 이용하는 방식으로, 접촉식이 에너지소산에서 월등히 우수한 것으로 나타났다. 자력마찰 댐퍼를 제작하여 동적 실험을 수행하여 자력마찰의 특성을 파악하였다. 자력에 의한 마찰은 일반마찰과 동일한 거동을 보였으며, 진동수가 증가에 따라 마찰계수가 거의 변하지 않는 것으로 파악되어 주파수 민감도가 없는 것으로 나타났다. 선압축 고무스프링은 강체-선형거동을 보이는데, 이와 자력마찰을 합성하면 깃발모양 거동의 스마트 댐퍼 개념을 제시하였다. This study suggests a method to embody a smart damper using magnetic friction and rubber springs. In this study, energy dissipation capacity of permanent magnets with and without contacting on a magnetic substance. Non-contacting method uses reaction from magnetic induction, and contacting method uses friction; the contacting method is superior to dissipate energy. After manufacturing a magnetic-frictional damper, this study conducts dynamic loading tests and investigates the characteristics of the damper. The magnetic-frictional damper shows the same frictional behavior with other types of friction and frictional coefficient of the damper does not vary so much with increasing loading frequency. A precompressive rubber spring shows rigid-elastic behavior and presents a flag-shaped behavior combining with magnetic friction, which can a smart damper.

On the limiting of vibration amplitudes by a sequential friction-spring element

The possibility of using an additional sequentially connected friction spring element in order to reduce vibration amplitudes both for the self-excited oscillations and for the forced vibrations is discussed in the paper. The analysis is based on the averaging technique for systems with “slave variables” and demonstrates two main effects: damping during slipping in the additional element and fast switching between different natural frequencies due to alternating sticking/slipping phases. Analytic predictions for the oscillations’ amplitudes are obtained as steady state solutions of the equations governing slow motions of the system. The obtained analytic results enable optimal choice of friction in order to achieve maximal damping effect in case of the forced vibrations. The reasonable choice of the friction by the self-excited vibrations is a compromise between the acceptable amplitude and the robustness of the corresponding limit cycle. The asymptotic results are confirmed by numeric simulations.

Research of Resonant Machine Nonlinear Vibrating Characteristics

Studying the core component of the resonant machine by building the bench test system, utilizing the nonlinear analysis function of Abaqus/Explicit to solve the problem that the rigid-flexible coupling model can`t take the material nonlinearity into adequate consideration. Simulating the nonlinearity of the vibrating beam by doing time integration over the kinematic equation to obtain an accurate and reliable result. Firstly, simplifying the bench testing system to simulating the low frequent vibration; And then, comparing the acceleration root value between the test data and the simulating result on the characteristically point to check the reliability and accuracy of the simulation; By studying the hammer vibrating amplitude curve and shear stress curve changing along the rubber spring thickness, providing a preference for the optimization.

Static Analysis of a Laminated Rubber-Metal Spring Using Finite Element Method

The laminated rubber-metal spring has been widely applied for earthquake vibration isolation which deals mainly for horizontal motion at a very low frequency input. This article presents the effect of a vertical vibration input, which is also aimed at applying the laminated spring for high frequency excitation. Static analysis is discussed here using the Finite Element Analysis (FEA) to observe the stress and strain distribution as well as the safety factor of the isolator due to the axial force. Solid rubber spring experiences greater deformation while it reduces for the laminated rubber-metal spring as more plates are embedded in the rubber. However, higher stress distributions occur on spring with multiple plates compared to solid rubber and the stress concentrate on steel plate layers. Strain distribution was observed to be high at solid rubber spring and it is decreasing on the laminated rubber-metal spring. The critical part for the strain distribution in the laminated rubber-metal spring is in the rubber layers.

Research on Feed-Forward Controller for Electronic Throttle Control of GDI Engine Based on Nonlinear Model

The nonlinear Hammerstein model was designed. The model was used to compensate the dynamic behavior of an electronic throttle body at different operating conditions. It consisted of a static nonlinear function and a dynamic linear function. The static nonlinear function was used to representing the coulomb friction and limp-home return springs and the dynamic linear function was used to representing dynamic piecewise-linear characteristic. An observer model, known as kalman was used for the on-line throttle position and angular velocity estimation. The control strategy was designed which combined the feed-forward control based on Hammerstein model and feedback control based on proportional-integral-derivative (PID) controller. The control structure has the quick response characteristic of the feed-forward control and disturb compensation characteristic of the feedback control. The experimental results revealed that the dynamic position control delay less than 100ms, the static position error less than 0.5o and the controller satisfied requirement of GDI for precise in-charge control.

1992 Northeim train crash – A root cause analysis

Shortly after midnight on 15th November 1992, a severe train crash was caused by the break off of a buffer from a tool and gear wagon of a freight train. The buffer fell between the rails, tumbled, and then lifted one axle of a following freight wagon off the rails. Several freight wagons derailed in the station of Northeim, Germany, blocking the adjacent track. A night train travelling on that blocked track was already too close (only 180m) to stop, despite emergency braking initiated immediately and automatically by the track signalling system. When the night train crashed into the freight wagons, some of its coaches were heavily damaged. Eleven people were killed, and 51 injured, some of them seriously.The task for failure analysts was to find out why the buffer broke off from the front frame of the tool and gear wagon. Therefore, the material of the attachment, the front frame, and the welds were tested. Chemical composition, hardness, and microstructure were allowable. The welds showed imperfections which were determined not to be causal. The fracture surfaces had graded corrosion – which again was not causal – and beach marks that depicted fatigue cracks before final fracture.The cause for the break off was the fact that the front frame had been repaired at this same buffer attachment some years before and that the repair patch used was thinner than the original front frame profile.Additionally, the force characteristics of the buffer showed reduced stroke but increased forces which was due to several friction springs that had been broken for a long time. The buffer forces in service were assessed from standards, literature, and the deformations of the attachment. The in-service stresses at the welds were estimated using FEM analysis. High cyclic stresses at the welds resulted in fatigue cracking and finally break off of the attachment with the buffer.

Nonlinear Seismic Response Analysis Model and Experimental Verification for Pile Foundation of Bridge Structure

Through analysis and comparison of some nonlinear seismic response analysis models for structures of bridges with pile foundation, considering the effect of deformation performance of pile foundation whose nonlinear properties of foundation and the component are taken into account, this paper presents an improved model relatively. In order to verify the rationality of the improved model proposed in this paper, the calculation and analyses of the test model of a single pier with pile foundation through pushover are done, and the results are compared with the experiment results.The pile foundation does not damaged under seismic load; The improved model can reflect material nonlinearity of the actual soil contact between soil and pile, and the dispersed spring model can be better to simulate the postural nonlinear of pile-soil contact and separation; at the same time, we need to consider vertical friction spring in the pile side.

The Study of the Pendulum with Heavy Neo-Hookean Rod

The present paper is a generalization of the problem of a rubber spring pendulum discussed by Bhattacharyya in 2000 and Stănescu in 2011, which studied the case of the neo-Hookean rod without mass. In our paper we consider that the mass of the neo-Hookean rod is not negligible and its deformation is realized such that at any moment of time the rod can be treated as a homogeneous rigid bar of variable length. Using the second order Lagrange equations we obtained the equations of motion in the most general case and we identified as particular cases the situations presented in the bibliography. We also performed a study of the equilibrium positions and their stability. A study of the small oscillations about the stable equilibrium positions is realized too. The theoretical results are finally compared to those obtained by numerical simulation.

Vibration Isolation Analysis of Vibrating Screen with Two-Mass and High Energy

To break through the drawbacks of the one-mass vibrating screen like plugging screen, high noise and etc., a new vibration screen with two-mass and high energy which could generate transient high vibration intensity was analyzed. To meet the requirements of energy-saving and system stability, a spring with nonlinear and hard features was used in the main vibration system. In this case, the springs stiffness could change along with the vibration intensity. The stiffness of the vibration isolation spring could be determined by analyzing the vibration isolation coefficient, and then the hollow cylindrical rubber spring with internal damping was adopted in the vibration isolation system. On the one hand, this vibration isolation spring could effectively absorb transient high vibration intensity which passed from main vibrating spring to the lower mass. On the other hand, it could achieve good effect of vibration isolation between the lower mass and the foundation. Base on field testing, the vibration intensity was increased by 28%, meanwhile, the noise was reduced by 4% and the impact vibration to foundation was reduced by 24% , which successfully solved the plugging screen problem and also verified the validity of the vibration isolation system.

Robust tracking control of automotive throttle system without current sensor

Electronic throttle system has gained considerable interests recently. High control performance of this system is essential for both safe operations and possible replacements of mechanical counterparts. However, several inherent obstacles exist for the controller design of such system. First of all, the electronic throttle body exhibits several high non-linear effects, such as stick-slip friction, black slash, and discontinuous spring, etc. Secondly, variations of system parameters due to product variability causes non-uniform system behaviour. This paper aims to design a model-based robust tracking controller for such system. The developed controller exhibits several unique features such as robustness to both parameter uncertainties and noise, elimination of current sensor, etc. Theoretical analysis is provided in conjunction with discrete control algorithm implementation on a reliable continuous model to verify performance of the method. The efficacy of the approach is clearly shown.

An Innovative Experimental Setup for Laboratory Tests of Fine Blanking Process

Fine blanking process can produce parts with accurate cutting edge quality. Studying the effects of process parameters on accuracy and quality of fine banking products are usually expensive. In this paper, an innovative idea has been introduced for a set of fine blanking test rig which is not as complicate and expensive as standard fine blanking dies but it could be used alternatively for limited laboratory works. The main concept of the rig is based on manual adjustment of counter punch force and blank holder force by means of rubber spring and torque meters respectively. As a case study, the effect of counter punch force of fine blanking process in a 2mm thickness steel AISI-1006 sheet was studied by this test rig. The results show that increasing the counter punch force makes burr dimension on cutting edge to get smaller which means better quality of the product.