Application of dynamic vibration absorber for vertical vibration control of corrugated rolling mill

A variable mass tuned particle absorber is designed for the nonlinear vertical vibration control of the corrugated rolling mill in the composite plate rolling process.Considering the nonlinear damping and nonlinear stiffness between the corrugated interface,a three-degree-of-freedom nonlinear vertical vibration mathematical model of corrugated rolling mill based on dynamic vibration absorber control is established.The multi-scale method is used to solve the amplitude–frequency characteristic curve equation of the installed dynamic vibration absorber(DVA)system.The effects of stiffness coefficient and damping coefficient on the amplitude–frequency characteristic curve are analyzed.The expressions of the dynamic developed factor of the corrugated roll are derived,and the influence laws of mass ratio,frequency ratio and damping ratio on the dynamic amplification factor are analyzed.The optimal parameters of the DVA are obtained by adaptive genetic algorithm.The control effect of the DVA on the nonlinear vertical vibration is studied by numerical simulation.The feasibility of the designed dynamic absorber is verified through experiments.The results show that the designed dynamic absorber can effectively suppress the vertical vibration of the corrugated roller.

Interfacial bonding mechanism of Cu/Al composite plate produced by corrugated cold roll bonding

Corrugated cold roll bonding(CCRB) produces metal composite plate with improved mechanical properties compared with conventional methods,but the interfacial mechanism is not fully understood.Here,Cu/Al composite plate with good plate shape was produced by CCRB,and the bonding mechanism and strength along the corrugated interface were studied by experiments and finite element simulations.The results showed that the average bonding strength of Cu/Al composite plate produced by CCRB was nearly twice that of conventional composite plate at an average reduction of 40% during rolling.Strong friction shear stresses occurred at the interface of the corrugated composite plate,which promoted the plastic deformation of the metals and accelerated the rupture of the brittle interfacial layer.Electron backscattered diffraction analysis showed that higher degrees of grain elongation and refinement occurred in the matrices at the front waist and trough due to the stronger normal and shear stresses.Energy-dispersive spectroscopy line scans showed that the thickest atomic diffusion layer occurred at the front waist.The present combination of experimental and computational analyses provides insights into the underlying mechanism of mechanically improved metal composites prepared by CCRB.

Interface structures and mechanical properties of corrugated + flat rolled and traditional rolled Mg/Al clad plates

The corrugated + flat rolling(CFR) and traditional rolling(TR) methods were used to prepare Mg/Al clad plates using AZ31 B Mg and 5052 Al plates, and the interface morphologies and mechanical properties of the resulting clad plates were compared. Examination of the microstructures of the plates showed that the TRed Mg/Al clad plate presented a straight interface, while a corrugated interface containing fractured intermetallic particulates was observed for the CFRed plate due to the inhomogeneous strain induced by the corrugated roller. During the CFR process, the corrugated roller can accelerate the rupture of the substrate work-hardening layers and facilitate the mutual extrusion of fresh metals to enhance the interface bonding. Compared with the traditional basal texture of the Mg alloy, the CFR process can change the texture morphology, thereby enhancing the plastic deformation ability of the Mg plate. Tensile tests showed that the CFRed Mg/Al clad plate exhibited a higher ultimate tensile strength(UTS, 316 MPa), which was~ 8% higher than that of the TRed plate(293 MPa). In addition, the bending curve of the CFRed clad plate was smooth and there was no stress sudden drop phenomenon in the bending process. The higher UTS and excellent bending properties of the CFRed clad plate could be attributed to the enhanced coordinated deformation ability of the substrates induced by the corrugated interface, grain refinement, and the change in the Mg alloy texture morphology.