發(fā)布時(shí)間：2018-04-17 23:03

  本文選題：大跨橋梁 + 阻尼�。� 參考：《鐵道科學(xué)與工程學(xué)報(bào)》2017年08期

【摘要】：提出一種基于連續(xù)跳車激振的大跨度橋梁阻尼識(shí)別的強(qiáng)迫振動(dòng)法。該方法利用"共振"原理,讓車輛以合適速度連續(xù)駛越障礙物使主梁經(jīng)受與橋梁某階頻率相同的周期性脈沖荷載,使橋梁產(chǎn)生較大振幅的振動(dòng),從而增強(qiáng)測試信號(hào)的信噪比。給出基于連續(xù)跳車激振的結(jié)構(gòu)阻尼比識(shí)別的基本理論,并以一大跨度懸索橋?yàn)槔M(jìn)行動(dòng)力學(xué)仿真。復(fù)模態(tài)分析表明,當(dāng)車輛固有頻率是橋梁某階受測模態(tài)頻率的5倍以上時(shí),車輛振動(dòng)對受測模態(tài)阻尼比影響很小。采用連續(xù)跳車激勵(lì),當(dāng)相鄰障礙物的間隔△x與行車速度V和受測模態(tài)的固有周期T之間滿足△x=VT,可以激振起橋梁大幅振動(dòng)。當(dāng)噪信比較小時(shí),可以較準(zhǔn)確地識(shí)別1階反對稱模態(tài)阻尼比;隨著信噪比的降低,阻尼比識(shí)別結(jié)果精度有所降低。
[Abstract]:A forced vibration method for identifying the damping of long span bridges based on continuous jump vibration is proposed.By using the principle of "resonance", the vehicle can continuously drive over the obstacle at a suitable speed to make the main beam undergo the periodic pulse load with the same frequency as the bridge, so that the bridge produces a large amplitude of vibration, thus enhancing the signal-to-noise ratio of the test signal.The basic theory of structure damping ratio identification based on continuous jump vibration is presented, and the dynamic simulation of a long-span suspension bridge is carried out.The complex modal analysis shows that the vehicle vibration has little effect on the damping ratio of the tested modes when the natural frequency of the vehicle is more than 5 times of the measured modal frequency of the bridge.Using continuous jump excitation, when the interval x of adjacent obstacles and the driving speed V and the natural period T of the measured mode satisfy x / V _ T, the bridge can be excited to vibrate greatly.The first order antisymmetric mode damping ratio can be accurately identified when the noise signal ratio is small, and the accuracy of the identification result is decreased with the decrease of signal-to-noise ratio (SNR).
【作者單位】： 湖南大學(xué)風(fēng)工程與橋梁工程湖南省重點(diǎn)實(shí)驗(yàn)室;湖南省交通規(guī)劃勘察設(shè)計(jì)院;
【基金】：國家自然科學(xué)基金資助項(xiàng)目(51422806,51278189)
【分類號(hào)】：U441.3
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本文編號(hào)：1765678