In this study, a laminated composite damping structure (LCDS) with metal rubber (MR) as matrix and silicone rubber (SR) as reinforcement has been designed. The embedded interlocking structure formed by the multi-material interface of the LCDS can effectively incorporate the high damping characteristics of traditional polymer damping materials and significantly enhance the adjustable stiffness of the damping structure. Based on the periodic cyclic vibration excitation, dynamic tests on different laminated structures were designed, and the damping performance and fatigue characteristics under periodic vibration excitation of the LCDS, based on MR and SR, were explored in depth. The experimental results exhibited that, compared to single-compound damping structures, the LCDS with SR as reinforcement and MR as matrix has excellent stiffness and damping characteristics. The incorporation of the silicon-based reinforcement can significantly improve the performance of the entire structure under cyclic fatigue vibration. In particular, the effects of material preparation and operating parameters on the composite structure are discussed. The effects of MR matrix density, operating frequency, amplitude, and preload on the stiffness and damping properties of the MR- and SR-based LCDS were investigated by the single factor controlled variable method. The results demonstrated that the vibration frequency has little effect on the LCDS damping performance. By increasing the density of the MR matrix or increasing the structural preload, the energy dissipation characteristics and damping properties of the LCDS can be effectively improved. With the increase in vibration excitation amplitude, the energy consumption of the LCDS increases, and the average dynamic stiffness changes at different rates, resulting in the loss factor decreasing first and then increasing. In this study, a damping structure suitable for narrow areas has been designed, which overcomes the temperature intolerance and low stiffness phenomena of traditional polymer rubber materials, and provides effective guidance for the design of damping materials with controllable high damping and stiffness.
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.
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.
A novel coated damping structure for metal rubber (MR) of bellows is designed based on large-size metal rubber sheets. This structure is dynamically tested in the bending direction at normal temperature. According to the test results, a model of the nonlinear elastic restoring force is set up, which describes the dynamic characteristics of the coated damping structure for metal rubber of bellows, and identifies the parameters of the model. The results show that the coated damping structure for metal rubber of bellows has a strong damping energy dissipation ability, its dynamic vibration characteristics are related to the vibration amplitude and frequency, and it is a complex nonlinear hysteretic system with multiple damping components. After identification of the parameters, the model of nonlinear elastic restoring force shows highly accurate results.
This paper aims to investigate the nonlinear dynamic properties of a two-point and symmetrically supported pipeline bracket system coated with the damping element using an elastic-porous metal rubber. The dynamic model of the studied two-point and symmetric pipeline system was established based on impulse response matrix for accurate and reliable description on its nonlinear behaviours, e.g., energy dissipation and loss factor. The experimental verification of the developed model was performed by means of dynamic test as well as the analyses of nonlinear damping characteristics. The experimental results show a good agreement with the prediction results obtained from the proposed dynamic model. This work provides an alternative method to investigate the dynamics of pipeline vibration system equipped with a damping structure.