The vertical vibration often occurs during the rolling production, which has an influence on the accuracy of rolling mill. in order to effectively suppress the vertical vibration of the rolling equipment, the rolling mill model with vibration absorber device was established. based on the main resonance singularity of the rolling mill system, the best combination of opening parameters was obtained.
According to the hill rolling force formula, taking particular account of the influence from horizontal vibration of rolled piece in roll gap, a dynamic rolling force model is analyzed. considering the interaction between vibration of strip and roll, the dynamic vibration model of rolling mill is established. on this basis, the time delayed feedback is introduced to control the vibration.
An effective dynamic model is the basis for studying rolling mill vibration. through analyzing characteristics of different types of vibration, a coupling vibration structure model is established.
The dynamic model of 4h mill, which couples with the rolling process model, the mill roll stand structure model, and the hydraulic servo system model, is built by analyzing the vibration process of cold rolling.
Vertical vibration model of strip mill is established by considering piecewise nonlinear constraint arising from hydraulic cylinder. the approximate analytical solution of the model is obtained by incremental harmonic balance (ihb) method. the harmonic frequencies not conducive to stability are produced because the nonlinearity of the piecewise constraint. bifurcation behavior of.
Vibration damping. vibration damping materials are an effective retrofit for controlling resonant tones radiated by vibrating metal panels or surface areas. in addition, this application can minimize the transfer of highfrequency sound energy through a panel. the two basic damping applications are freelayer and constrainedlayer damping.
In this paper, we investigate the rolling interface instability characteristics caused by the coupled motion of strip and the roll system. based on the experimental test, the dynamical behaviors of the rolling mill under the motion of roll system and the strip show multimodal vibration phenomenon, which are consistent with the variation of rolling interface force and energy parameters. then.
C oupling vibration model for hot rolling mills and its application. jimin w u, x iaoqiang y an issn p rint 13928716, issn o nline 25388460, k aunas, l ithuania 1797 is calculated by: 8 1 0 t 6 6 :j ; 5, (1) where 0 is the number of data; t :j ; is the discrete test data. the timedomain and frequencydomain graphs for different mill modulus control gains are.
Committed to the vibration characteristics and instability mechanism of rolling mill. e models for the third octave chatter of vibrational instability during rolling were presented and discussed by meehan 11. niroomand et al. 12 introduced wave propagation theory to explain chatter mechanism in tandem cold rolling mills. kapil et al. 13.
Comprehensive kinetic model of the rolling process and vertical vibration model of rolling mill system. however, the existing rolling friction models are mostly steadystate models 12, 13 that cannot eﬀectively reﬂect lubricated friction state changes in the deformation zone caused by the parameters change in the rolling dynamic process.
This paper studies the torsional vibration suppression control problem for the nonlinear rolling mill main drive system with performance constraint requirements and unknown measurement sensitivities. firstly, considering the nonlinear friction between the roll gaps, a torsional vibration model of the main drive system of rolling mill is established. then, with the asymmetric performance.
Dyicheng chen department of mechanical engineering, institute of technology, taiwan, republic of china yeongmaw hwang national sun yatsen university, taiwan, republic of china 1. learn more about chapter 8: analysis and experiment on void closure behaviour inside the sheet during sheet rolling processes on globalspec.
The rolling process is determined by the interaction of a number of different movements, during which the relative movement occurs between the vibrating roll system and the rolled piece, and the roll systems vibration interacts with the strips deformation and rigid movement. so many parameters being involved leads to a complex mechanism of this coupling effect.
Friction equation of the roll gap and the distribution model of the forward rolling stress in the deformation zone and discussed the vertical vibration mechanism and stability of the cold rolling mills 13. nevertheless, the coupling relationship between strip steel vibrations and torsional vibration of main drive system was.
Frictioninduced vibration is a typical selfexcited phenomenon in the rolling process. since its important industrial relevance, a rolling mill verticaltorsionalhorizontal coupled vibration model with the consideration of the nonlinear friction has been established by coupling the dynamic rolling process model and the rolling mill structural model. based on this model, the system stability.
Considering the two kinds of nonlinear constraints of rolling mill hydraulic cylinder, spring force and friction force, the vibration model of rolling mill system is established. the amplitude frequency response equations are obtained by using the average method. comparing the time history curves of vertical vibration displacement of rolling mill system under the nonlinear spring force and.
On the basis of rolling theory, lubrication and friction theory, and mechanic vibration theory, the vertical vibration model for unsteady lubrication in rollsstrip interface was presented. the geometry model of roll gap, the unsteady lubrication model of rollerstrip working interface, the distribution model of normal rolling stress and.
The cold rolling process is a high speed, transient, and timerelated metal machining molding process .as cold rolling mill is a multimass and rotary motion object system, the vibration as an implicit factor commonly exists in the course of its operation, but it usually does not apparently present due to the conditional constraints of factors such as various rolling processes, equipment, and.
The verification results showed that the established model could accurately predict the minimum friction and the friction balance in tandem rolling mills. the model was utilized to design the optimal rolling conditions to expand the stability range of the friction and improve mill vibration stability.
First, a dynamic model of the rolling process that utilizes homogeneous deformation theory will be established that includes the material strainhardening and work roll flattening effects. by coupling this dynamic rolling process model with a structural model for mill stands, a singlestand chatter model in a statespace representation will be.
It is important to study the vibration of rolling mills to improve the stability of rolling production. a dynamic rolling process model is established by considering the elastic recovery of the exit strip and the influence of multiroll equilibrium, and the accuracy of the model is verified by experimental data. on this basis, based on the distribution of friction force in the deformation zone.
Manganese bronze and brass co. ltd. (the), caxton house, westminster, london, s.w.1, own foundries, rolling mills and extruding mills in london and ipswich. their oilite selflubricating bearings have been approved by the air ministry for loads up to 3,000 lb. per sq. in.
The dynamic characteristics in a rolling process have been investigated with various methods, but a mathematical model to predict actual chatter vibration has not been established. in this paper, we propose a mathematical model of a cold rolling mill to predict chatter vibration. the mathematical model was verified by experiment and theoretical analysis. the chatter frequency.
Investigations have prove n that the stability of ultrasonic vibration is a critical factor of ultrasonic machining 6–11. t he impedance characte ristics of ultrasonic transducers depend on.
Models for the occurrence of the vibrational instability during rolling known as third octave chatter are presented and discussed. an analysis of rolling mill chatter was performed for the purpose of identifying characteristics of the vibrations and.
In this twopart paper, stability of tandem mills is investigated. in part 1, statespace models of single and multistand chatter are formulated in a rigorous and comprehensive mathematical form. then, the stability of the rolling system is investigated in the sense of the single and multistand negative damping effects.
Mill chatter in tandem cold rolling mill is a major rejection to the quality and production of the strips. in most mill vibration models, either the roll mass is usually limited to vibrate in.
Mill chatter in tandem cold rolling mill is a major rejection to the quality and production of the strips. in most mill vibration models, either the roll mass is usually limited to vibrate in vertical direction and verticalhorizontal directions, or the multiple rolls system is simplified to a single mass system. however, the torsional chatter is also a typical type of mill chatter, and the.
Mill chatter is a major restriction in the highspeed rolling of highstrength and thin strips. to maintain mill stability, the friction coefficient must be kept within a certain range. unfortunately, there is no model to calculate the lower limit of the friction. in this paper, a new model is developed to capture the minimum friction coefficient.
Modal structural model and the model of the rolling process. regenerative effect is an important factor which may lead to instability in a rolling tandem mill 6, 10, 11, 21.
Models for the occurrence of the vibrational instability during rolling known as third octave chatter are presented and discussed. an analysis of rolling mill chatter was performed for the purpose of identifying characteristics of the vibrations and to determine any dependency on the rolling schedule. in particular, a stability criterion for the critical rolling speed is used to predict the.