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推导了简支梁在移动荷载列作用下的振动响应理论解,得到了简支梁发生共振及两类消振效应的车速计算公式,阐明了二者的发生机理。提出移动荷载作用下简支梁存在两类消振效应,第一类消振为单个荷载行为,第二类消振与荷载间距有关;发生消振效应时,已经离开桥梁的荷载所引起简支梁的自由振动抵消为零,桥梁的动力响应较小;消振发生的条件较共振更为严格,当车速同时满足二者的要求时,消振效应起主要作用,将出现共振消失现象;理论上通过调整车厢长与桥跨之比可避免共振现象发生。通过算例分析了两座简支梁在列车过桥时的动力响应,验证了理论分析的正确性。
The theoretical solution to the vibration response of simply supported beams under the moving load is deduced. The formula for calculating the vehicle speed with the resonance of the simply supported beams and the two types of vibration reduction effects is obtained, and the mechanism of the two responses is clarified. It is suggested that there are two types of vibration damping effect of simply supported beam under the action of moving loads. The first type of vibration damping is a single load behavior and the second type of vibration damping is related to the load spacing. When the damping effect occurs, the load that has left the bridge The free vibration of the beam cancels out zero and the dynamic response of the bridge is small. The condition of vibration damping is more strict than the resonance. When the speed meets the requirements of both, the vibration damping effect plays a major role and resonance disappears. Theory By adjusting the length of the car and bridge span to avoid the phenomenon of resonance. The dynamic response of two simply supported beams when crossing the train is analyzed by an example to verify the correctness of the theoretical analysis.