新型减震自复位附属结构在桥梁应用中的力学性能研究

发布时间：2018-11-02 18:53

【摘要】：NSD(negative stiffness device,简称NSD)为一种新型的负刚度减震机构,即在位移激励下能产生与位移方向一致的作用力的机构,将其内置于结构中可通过弱化结构以达到减震效果。现有系列研究表明:NSD具有较好的减震功效和自复位功能,且NSD机构是无需外部能源输入的被动控制的结构减震技术,其完全通过力学机制产生负刚度从而达到减震功效。NSD作为被动减震装置,一定程度上消除了主动、半主动控制装置能量输入大且不稳定的影响。目前基于NSD实现耗能能力的研究成果较少,因此,对改进型减震自复位负刚度机构的抗震机理分析显得尤为迫切。为了进一步改善既有负刚度机构的抗震性能,本文开发了增设与预压弹簧并行的辅助耗能元件的改进型减震自复位负刚度机构。以负刚度机构中预压弹簧刚度和预压位移作为设计参数,设计了5个足尺试件并采用商业有限元软件ABAQUS对其在水平低周往复荷载下的抗震机理进行了数值模拟。基于模拟数据处理,对其滞回特征、水平抗侧刚度和耗能能力等性能进行了对比分析。为了验证改进型减震自复位负刚度机构对结构的减震功效,本文设计了直柱式桥墩结构内置改进型减震自复位负刚度机构算例,并采用商业有限元软件ABAQUS对其在水平低周往复荷载下以及单向加载下了进行数值模拟。分析结果显示:预压弹簧刚度不仅影响负刚度对结构弱化减震的发展进程,且影响消压后对结构强化自复位的功效。预压位移设计值仅影响负刚度对结构弱化减震的发展进程。设置与预压弹簧并行的辅助耗能元件可提供耗散地震能的能力,从而进一步增强结构的减震效果。因此,改进型减震自复位负刚度机构实现了减震、耗能能力与自复位功效有机统一的性能设计目标。
[Abstract]:NSD (negative stiffness device, (NSD) is a new type of negative stiffness damping mechanism, which can produce force consistent with displacement direction under displacement excitation. It can be used to attenuate the structure by weakening the structure. The existing series of studies show that NSD has better damping effect and self-reset function, and that the NSD mechanism is a passive structural damping technique without external energy input. NSD, as a passive shock absorber, can eliminate the influence of active and semi-active control devices on the large and unstable energy input to some extent. At present, there are few researches on the energy dissipation ability based on NSD, so it is urgent to analyze the seismic mechanism of the improved self-reset negative stiffness mechanism. In order to further improve the seismic performance of the existing negative stiffness mechanism, an improved damping self-reset negative stiffness mechanism with auxiliary energy dissipation elements parallel to the preloaded spring is developed in this paper. Taking preloaded spring stiffness and preloading displacement in negative stiffness mechanism as design parameters, five full-scale specimens were designed and their seismic mechanism under horizontal low cycle reciprocating load was simulated numerically by commercial finite element software ABAQUS. Based on the simulation data processing, the hysteretic characteristics, horizontal lateral stiffness and energy dissipation capacity were compared and analyzed. In order to verify the effect of the improved self-reset negative stiffness mechanism on the structure, a calculation example of the modified self-reset negative stiffness mechanism for the straight column pier structure is designed in this paper. The commercial finite element software ABAQUS is used to simulate it under horizontal low cycle reciprocating load and unidirectional loading. The results show that the stiffness of preloaded spring not only affects the development process of the negative stiffness on the weakening and damping of the structure, but also affects the effect of strengthening the self-reset of the structure after the reduction of the pressure. The design value of preloading displacement only affects the development process of the negative stiffness on the weakening and damping of the structure. The ability of dissipating seismic energy can be provided by setting auxiliary energy dissipation elements parallel to preloaded springs, thus further enhancing the seismic absorption effect of the structure. Therefore, the improved self-reset negative stiffness mechanism achieves the performance design goal of the unity of damping, energy dissipation and self-reset efficiency.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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