【作者】 蒋春艳；

【导师】 魏建国；

【作者基本信息】 河北农业大学 ， 结构工程， 2008， 硕士

【摘要】 网架结构具有刚度大、自重轻、造型丰富美观、综合技术指标好等特点,是大跨度空间结构的主要结构形式之一。近年来,国内外学者对结构减震进行了较系统的研究并已应用于多高层结构,但将减震技术用于大跨网架结构研究较少,属于起步研究阶段。本文对大跨空间网架结构采用消能减震方法进行了研究,其中包括结构的消能减震计算模型和计算方法、模态分析、动力响应分析、阻尼器设置方案、阻尼器阻尼系数优化等。利用粘滞流体阻尼器对空间网架结构进行减震控制,粘滞阻尼器的工作性态为非线性性质,而常规结构部分则在弹性阶段工作。因而,对带粘滞阻尼器的空间网架进行动力分析属于局部非线性问题。本文在算法上采用适用于局部非线性问题的“快速非线性分析(FNA)”方法求解,此方法有较高的计算效率和精度。采用同时考虑下部支承结构和上部网架结构的整体协同工作模型,这更符合空间网架结构的实际工作状况。利用SAP2000有限元软件对结构进行建模,计算模型中网架部分采用空间杆系模型,下部支承结构采用空间梁柱模型,增加的阻尼器作为单独的阻尼单元计算。对常规结构部分进行模态分析,分析表明:网架结构动力特性复杂,自振振型大多以上部结构的竖向对称或反对称的振动和整体结构水平向振动为主,虽然在前十阶振型中出现了扭转振动,但由于阶数较大,对结构影响相对较小。文中采用粘滞流体阻尼器作为附加消能杆件,分析比较了五种不同的阻尼器布置形式。通过分析计算给出了较优的阻尼器布置方式,得到了阻尼器应设置在阻尼器两端有较大相对位移和速度的位置的结论,这样能使阻尼器获得较大阻尼力,起到较大的耗能作用。文中还就阻尼器的阻尼系数和阻尼器布置数量对结构减震效果的影响,以及不同频率特征地震波下结构的减震效果进行了分析,得到了有效减震的阻尼系数取值范围和较经济合理的阻尼器布置数量,这可以为工程设计人员提供很好的参考。不同的地震波激励,结构的响应可能相差较大,为了得到较准确的结果,需要采用多条地震波进行计算取其平均值。更多还原

【Abstract】 Space truss structure has characteristics of great rigidity, light dead weight, magnificent structure, and good synthetic technology index. It is one of the main large span structural styles. In recent years scholars at home and abroad made systematic research on structure vibration control which has been applied for tall buildings or high-rise buildings. However study on vibration control method applying for long-span space truss structures is few. In this paper research is applied to vibration energy dissipation method using for long-span space truss with respect to vibration energy dissipation calculation model and method, modal analysis, structure dynamic property, arranging energy dissipation mechanism, damping coefficient optimization and .Space truss structure uses viscous fluid dampers to reduce earthquake response. Working behavior of viscous dampers is nonlinear characteristic, but normal structures are in elastic stage, so dynamic analysis for space truss structure with viscous damper is partial nonlinear problem. The paper uses Fast Nonlinear Analysis to solve problems which is suitable for local nonlinear problems. The method is mentioned above is more effective and pricise.A study on the model of the interaction of space truss with supporing substructure is carried out by finite element software SAP2000. This model accords with actual working conditions of space struss structure. Three-dimensional finie element method is used as the calculating model for space truss. The space beam-column method is used as the calculating model for suppoting substructure. A damping unit is used as the calculating model for the additional damper. The modal analysis of normal structure indicates that the dynamic characteristic of space truss structure is complex, and the vibration mode of the model is mainly vertical and horizontal. The effect of restoration is little.By considering five different setting manners of viscous dampers, analysis of damping effect is carried out in the paper. The results indicate that the damper should be set at the place with the larger relative displacement and velocity. In this condition, the damper can get bigger damping force, and play a larger role in energy dissipation.By considering different damping coefficient and number of viscous damper and different seismic wave, analysis of damping effect is carried out in the paper too. The result indicates that the damping coefficient and number of damper have optimal values. That offers a good reference for engineering designers. The structures’ responses maybe have larger difference under different seismic waves. In order to get more accurate results, using many seismic waves to calculate and taking their average are necessary.更多还原