Many kinds of dampers are invented to reduce the dynamic responses due to earthquake or strong wind. Viscoelastic damper is a kind of commonly used passive control device for vibration mitigation of structures. Its energy dissipation characteristics are affected by environmental temperature and excitation frequency. In order to describe the complex characteristics of viscoelastic dampers changing with temperature and frequency, a new model — the equivalent standard solid model, which is based on the standard linear solid model and temperature-frequency equivalent theory, is proposed. The comparison results between experimental and numerical data of viscoelastic dampers show that the equivalent standard solid model can precisely describe energy dissipation behavior of viscoelastic dampers under different temperatures and frequencies. At the same time, 52 viscoelastic dampers are applied for seismic retrofit design on Xi’an Petrol Hotel, and the finite analysis for structures with and without dampers are carried out under frequent-earthquake and infrequent-earthquake excitations. The dynamic responses of structures with and without dampers are compared. Analytical results show that viscoelastic dampers can reduce the earthquake responses effectively, and they are high-performance energy dissipation devices.

Viscoelastic (VE) dampers are one of the most popular structural control devices, and serious efforts have been undertaken to develop their availability in civil engineering. However, the performance of VE dampers is dependent on the energy dissipation properties of VE materials. In this study, several kinds of VE materials based on different matrix rubbers were developed, and tests on VE dampers based on nitrile butadiene rubber (NBR) matrix and silicone rubber (SR) matrix were carried out. The results indicate that NBR matrix VE dampers have a high energy dissipation capacity, whereas SR matrix VE dampers have stable performance under different working conditions. To clarify the mechanical properties of VE dampers based on NBR and SR matrices, the equivalent higher-order fractional derivative model, which takes into account the effects of temperature and frequency simultaneously, is proposed. The numerical results using this model are in accord with experimental results.

Viscoelastic (VE) dampers are one of the most common earthquake mitigation devices. This paper addresses the mathematical modelling of VE dampers and the dynamic analysis of structures with VE dampers. In this paper, the equivalent standard solid model, a new mathematical model of VE dampers, is used to describe the influence of temperature on the energy absorption features of VE dampers. Elastoplastic time field analysis, frequency field analysis and shaking table tests are used to analyze responses of a 1/5 scale three-story reinforced concrete frame structure with and without VE dampers. Comparisons between the numerical and experimental results show that the VE dampers can be modeled by the equivalent standard solid model and that the VE dampers are effective in reducing the seismic responses of structures.

Advanced composite materials have excellent performance and broad engineering application prospects, and have received widespread attention in recent years. Advanced composite materials can mainly be divided into fiber-reinforced composite materials, laminated composite materials, matrix composite materials, and other composite materials. This article provides a comprehensive overview of the types and characteristics of advanced composite materials, and provides a comprehensive evaluation of the latest research on structural strengthening and resilience improvement in advanced composite materials from the perspectives of new methods, modeling optimization, and practical applications. In the field of fiber-reinforced composite materials, the hybrid technology of carbon fiber and glass fiber can achieve dual advantages in combining the two materials. The maximum increase in mechanical properties of multilayer sandwich RH plate by hybrid technology is 435.4% (tensile strength), 149.2% (flexural strength), and 110.7~114.2% (shear strength), respectively. In the field of laminated composite materials, different mechanical properties of laminated composite materials can be obtained by changing the deposition sequence. In the field of matrix composites, nano copper oxide particles prepared by nanotechnology can increase the hardness and tensile strength of the metal matrix material by 77% and 78%, respectively. In the field of other composite materials, viscoelastic materials and magnetorheological variants have received widespread attention. The development of composite materials benefits from the promotion of new methods and technologies, but there are still problems such as complex preparation, high cost, and unstable performance. Considering the characteristics, application requirements, cost, complexity, and performance of different types of composite materials, further improvements and innovations are needed in modeling and optimization to better meet practical engineering needs, such as the application of advanced composite materials in civil engineering, ships, automobiles, batteries, and other fields.