Metal rubber has been extensively used in recent years due to its several unique properties, especially in adverse environments. Although many experimental studies have been conducted, theoretical research on metal rubber is still in its infancy. In this work, a dynamic model for the nonlinear characteristics of pot-shaped metal rubber is established on the basis of the asymmetric dynamic model of the wire rope shock absorber and the trace method model. In addition, the corresponding parameters in the model are identified based on the parameter-separation method. The theoretical hysteresis loop obtained using the model and the measured hysteresis loop agree with each other. The results show that the asymmetric dynamic model can better describe the asymmetric dynamic characteristics of pot-shaped metal rubber. Furthermore, a pot-shaped metal rubber vibration reduction system is built to further verify the correctness of the model. This study provides an experimental reference and a theoretical basis for the practical application of pot-shaped metal rubber in the field of three-dimensional vibration reduction.
In this paper, a symmetrically coated damping structure for entangled metallic wire materials (EMWM) of pipelines was designed to reduce the vibration of high temperature (300 °C) pipeline. A series of energy dissipation tests were carried out on the symmetrically coated damping structure at 20–300 °C. Based on the energy dissipation test results, the hysteresis loop was drawn. The effects of temperature, vibration amplitude, frequency, and density of EMWM on the energy dissipation characteristics of coated damping structures were investigated. A nonlinear energy dissipation model of the symmetrically coated damping structure with temperature parameters was established through the accurate decomposition of the hysteresis loop. The parameters of the nonlinear model were identified by the least square method. The energy dissipation test results show that the symmetrically coated damping structure for EMWM of pipelines had excellent and stable damping properties, and the established model could well describe the changing law of the restoring force and displacement of the symmetrically coated damping structure with amplitude, frequency, density, and ambient temperature. It is possible to reduce the vibration of pipelines in a wider temperature range by replacing different metal wires.
1 January 2018 in Advances in Materials Science and Engineering
Metal rubber (MR) is an excellent damping material that is often used in practical engineering applications. The performance of MR in the nonforming direction is different from that in the molding direction, and research is rare; the anisotropy of MR is gradually revealed in many engineering applications because characterization and analysis of damping energy dissipation characteristics in the nonforming direction of cylindrical MR were carried out by the characterization method of damping materials. Based on the testing methods, dry friction and dynamic stiffness are taken as the main analysis points. By performing single‐factor control and orthogonal tests, the parameters affecting the energy dissipation and damping characteristics of MR are studied, and the main factors that cause changes in energy consumption and loss factor are analyzed. It is found that the influence of loading amplitude on damping energy is much higher than that of loading frequency, and the damping characteristic of MR is not sensitive to frequency. Therefore, the loading amplitude level of the actual environment should be considered first followed by the knitting technology in design of MR components.
The reduction of vibration in submarine pipeline systems at high temperatures has always been a difficult problem. This paper aims to reduce the vibration of pipeline systems by using coated metal rubber. A theoretical model of the cladding damping structure, formed on the basis of the bilinear hysteresis model, is established. The mechanical model of the single degree of freedom hysteretic system is linearly equivalent to using the linearization method. The theoretical analysis indicates that the regularity of the stiffness of metal rubber decreases, and the damping increases, with the increase of the excitation amplitude. Experimental verification confirmed this analysis after an experimental system for pipelines coated by metal rubber was developed. A method for preparing the thin sheet of metal rubber, which is the damping layer, was introduced. At the same time, the force transfer rate and the structural loss factor were proposed to characterize the damping performance of the cladding damping structure. The vibration absorption characteristics of the cladding damping structure, along with its forming density, number of coating layers, and excitation magnitude, are investigated by means of the experimental method. The results indicate that the damping performance of metal rubber decreases with the increase of forming density, and the damping performance of metal rubber increases with the increase of the number of cladding layers and the magnitude of excited vibration.