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地球磁场和人工磁场不断变化,会对甚宽频带地震计的簧片产生吸引而降低地震观测数据质量。将甚宽频带地震计分别采用宽背簧和窄拉簧悬挂,放置于赫尔姆霍兹线圈中间,测试地震计所受干扰;使用铍莫合金屏蔽罩罩住地震计,再次测试地震计所受干扰。测试结果表明:地震计垂直分向所受干扰严重,使用宽背簧支撑摆体运动的地震计所受干扰程度较大;铍莫合金屏蔽罩对参与测试地震计所有分向均有一定屏蔽效果。 相似文献
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将摩擦摆隔震体系应用在模块化钢框架结构中,研究摩擦摆支座对模块化结构整体性能的影响规律。基于ETABS有限元软件,考虑模块化节点刚域对结构刚度的影响,采用摩擦摆隔震体系对某模块化建筑示范综合办公楼进行基础隔震设计与研究,并进行了多遇地震作用下的弹性时程分析、设防烈度和罕遇地震作用下的弹塑性时程分析。分析结果表明,节点刚域对抗震结构地震响应的影响比对隔震结构地震响应的影响更大。FPS隔震体系在多遇地震作用下隔震效果不明显,在设防烈度及罕遇地震作用下能起到良好的隔震作用。罕遇地震作用下,隔震结构中仅发现少量梁铰,无柱铰出现,上部结构结构基本处于弹性,隔震效果显著。 相似文献
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根据空冷器的特点,利用ANSYS有限元软件建立了空冷器的有限元模型.用MPC184单元实现了力和力矩的加载,得到了空冷器的固有频率和振型.对空冷器在正常运行工况和地震荷载工况下进行了抗震性能计算分析,并根据RCC-M规范对空冷器在地震工况下的结构完整性进行了应力评定.结果表明在上述载荷作用下,空冷器和地脚螺栓的应力状况满足RCC-M规范的要求. 相似文献
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《地震工程与工程振动》2021,41(5)
隔震支座对桥梁抗震有重要意义,优化支座的参数可有效提升隔震效率。以一座三跨连续梁桥为例,建立了考虑桩-土-结构相互作用的有限元模型。将铅芯橡胶支座的特征强度及初始刚度视为优化变量,以最小化桥梁结构的系统地震易损性为目标。通过动力时程分析,得到支座参数对桥梁系统地震易损性的影响规律,确定支座参数的合理区间。高斯过程模型用来取代耗时的动力时程分析,降低隔震支座优化设计的计算成本。分析结果表明:铅芯橡胶支座的特征强度和初始刚度对桥梁系统地震易损性有明显影响;支座优化设计有效降低了桥梁系统地震易损性,大幅减小支座的剪切应变,提高了支座的隔震效率。 相似文献
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结合长联大跨连续梁桥的特点,以1座(65+123+156+123+10×90+55)m长联大跨摩擦摆支座隔震连续梁桥为背景,建立了全桥三维有限元模型,运用非线性时程分析法,分析了地震动输入模式、地震动强度、摩擦摆支座参数对该桥内力、位移和能量响应的影响。研究结果表明:(1)长联大跨连续梁桥布置摩擦摆支座,可有效延滞固定墩顶有效主梁质量效应,实现全桥协同抗震。大部分地震能量可通过支座滞回耗能散耗,大幅降低了该桥固定墩地震能量耗散需求。(2)长联大跨连续梁桥减隔震设计中,建议采用水平单向+竖向地震组合进行内力设计,采用三向地震组合进行位移设计。(3)强震作用下,支座摩擦因数取0.029~0.034时该桥隔震性能最优。 相似文献
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短周期地震计主要用于观测地方性的微小地震,用速度传感器设计的反馈式短周期的地震计的工作参数稳定性不好,是国内外观测实践都证实了的问题。借鉴位移传感反馈地震计工作参数偏差较低的思路,介绍了通过采用函数变换方法设计速度传感反馈地震计的解决方案。用函数变换方法设计的速度传感反馈地震计,既实现了加大负反馈深度又不降低噪声指标的双重目标,有加深负反馈和由闭环反馈生成的闭环周期位于通带外的优点。即便是机械摆受到环境变化的影响或随时间推移而出现了漂移或老化,其对通带内的幅频特性的影响亦较小。由函数变换电路生成摆函数的工作周期及工作阻尼与机械摆的参数完全无关,仅取决于变换电路中的两个电阻和两个电容的精度。 相似文献
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The Russian electrodynamic seismometer model S-5-S has been adapted for the measurement of rotational ground motion. The mechanical system of the original S-5-S seismometer consists of electrodynamic sensing and damping transducer coils mounted on an asymmetrical double-arm pendulum. This pendulum is suspended on a footing using two pairs of crossed flat springs, which operate as the axis of rotation. The pendulum is stabilised by an additional spring. The S-5-S can be used either as a vertical or as a horizontal sensor. The adaptation of the S-5-S seismometer described below involves removal of the additional spring and installation of an additional mass on the damping arm. Strain gauge angle sensors are installed on one pair of the crossed flat springs. The main dynamic parameters of the rotational seismometer created in this way, i.e. the natural period and damping, are controlled electronically by feedback currents proportional to the angular displacement and angular velocity, both fed to the damping transducer coil. This new seismometer, named the S-5-SR, enables measurement of the rotational component of ground motion around the horizontal or the vertical axes. The output signal from this S-5-SR seismometer can be proportional either to rotational displacement or rotational velocity. 相似文献
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The results of theoretical and experimental studies of the basic characteristics of seismic receivers with quartz sensors are presented: the working frequency band is 0.1–30 Hz, the dynamic range is 120 dB, and the temperature coefficient of pendulum displacement is 0.2 μm/°C. The device’s characteristics are highly time-stable and can operate for several years without tuning. A system where the pendulum is automatically (passively) set into the working position is proposed. 相似文献
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针对村镇房屋隔震设施薄弱的问题,本着低成本、易施工的原则,设计了一种玄武岩纤维混凝土材料的摩擦摆隔震支座。将该新型支座与传统钢制摩擦摆支座进行拟静力试验,研究了该新型支座在相同的竖向荷载作用,不同频率下的干摩擦和润滑摩擦两种工况的支座的滞回性能,得出了该新型支座的基本力学性能,通过利用SAP2000有限元模型对采用该新型支座的隔震结构进行了动力时程分析,并且将该新型支座与传统钢制摩擦摆支座在滞回性能、构造方式和经济性三方面进行对比分析。结果表明:玄武岩纤维混凝土摩擦摆支座的滞回性能略低于钢制摩擦摆支座滞回性能,该支座隔震效果显著且易模性好,便于施工,造价低廉,适用于低层村镇房屋隔震设计与施工。 相似文献
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选取2019年3月—8月河南平顶山市宝丰县平煤矿区发生的ML 2.0—2.9天然地震、爆破、塌陷等9次震动事件,在区域地质构造背景和波形特征分析基础上,采用短时傅里叶变换(STFT)方法开展时频波谱分析,提取不同类型事件的时频特征。结果显示:(1)天然地震频率成分丰富,且高、低频分布均匀,P波在约3 Hz和8 Hz处存在2个峰值,S波存在多个峰值;(2)爆破事件的时频谱相对集中,以低频为主,P波频率峰值约5Hz,信号主频随时间变化,大致呈线性降低至1—2 Hz;(3)塌陷事件频率成分以4 Hz以下的低频为主,P波无明显峰值且频率成分单一,主频出现在2 Hz左右的面波。本文结果可为今后该矿区震动事件类型判断提供参考依据。 相似文献
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采用数值仿真的方法建立了动圈式检波器的仿真模型,推导检波器传递函数,通过对实际动圈式检波器频率特性的测试,验证了动圈式检波器数值仿真模型的正确性,分析动圈检波器频率响应特性,分别对动圈式检波器的自然频率、灵敏度、阻尼比进行仿真,对不同自然频率、灵敏度、阻尼比对检波器输出频率特性的影响进行了分析,使用二阶二次型反馈补偿方法,设计检波器低频补偿结构,结果表明:数值仿真模型与实际检波器的频率响应一致,补偿结构使检波器自然频率由2 Hz降低至0.2 Hz. 相似文献
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V. A. Chistyakov 《Seismic Instruments》2011,47(1):8-14
The problems related to design of a portable seismic sensor working in a frequency range of 0.01–40 Hz are considered. Its
main parts (pendulum, capacitive displacement transducer, magnetoelectric converter), structural diagram, and amplitude-frequency
characteristic are described. 相似文献
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This paper presents the dynamic soil–structure analysis of the main telescope T250 of the Observatorio Astrofísico de Javalambre (OAJ, Javalambre Astrophysical Observatory) on the Pico del Buitre. Vibration control has been of prime concern in the design, since astrophysical observations may be hindered by mechanical vibration of optical equipment due to wind loading. The telescope manufacturer therefore has imposed a minimal natural frequency of 10 Hz for the supporting telescope pier. Dynamic soil–structure interaction may significantly influence the lowest natural frequency of a massive construction as a telescope pier. The structure clamped at its base has a resonance frequency of 14.3 Hz. A coupled finite element–boundary element (FE–BE) model of the telescope pier that accounts for the dynamic interaction of the piled foundation and the soil predicts a resonance frequency of 11.2 Hz, demonstrating the significant effect of dynamic soil–structure interaction. It is further investigated to what extent the coupled FE–BE model can be simplified in order to reduce computation time. The assumption of a rigid pile cap allows us to account for dynamic soil–structure interaction in a simplified way. A coupled FE–BE analysis with a rigid pile cap predicts a resonance frequency of 11.7 Hz, demonstrating a minor effect of the pile cap flexibility on the resonance frequency of the telescope pier. The use of an analytical model for the pile group results in an overestimation of the dynamic soil stiffness. This error is due to the large difference between the actual geometry and the square pile cap model for which the parameters have been tuned. 相似文献