摊铺机熨平板冲击与振动耦合压实特性研究

Investigation of paver screed on coupling compaction characteristics considering shock and vibration

为了提高沥青摊铺机对铺层混合料的初始密实度,针对摊铺机熨平板上的振捣和振动压实装置与材料组成的动力学压实系统,考虑振捣器压实物料时对熨平板产生的反作用力,将振捣器的冲击作用简化为周期性矩形波,采用傅里叶级数对振捣激励进行表达,建立了振捣激励和振动激励共同作用下的压实系统动力学模型,分析不同的振捣频率与振动频率对熨平板动态力学性能的影响,并对振捣与振动的耦合压实作用进行计算分析。探讨铺层材料的摊铺密实度与频率变化特性曲线,并进行仿真计算和试验研究,结果表明:熨平板的最大响应峰值出现在共振频率处,在高于共振频率区段,响应幅值相比于最大峰值降低了23%,此时铺层压实效果好,熨平板工作平稳;振捣器对铺层的密实作用大于振动器,在振捣和振动的耦合压实作用下,作用于熨平板的激励存在3个主频成分,以激起被压材料中不同固有频率的复杂成分,为铺层压实过程产生多方位共振提供基础;在研究高密实振动熨平板对铺层混合料的振动密实特性时,除了要分析振动频率接近于铺层的固有频率的主共振以外,还应注意振捣器的冲击作用并考虑振动与振捣的耦合对铺层混合料的压实效果。研究结论可为摊铺机熨平装置振动参数的选择提供依据。

To improve the initial density of a paving mixture behind the paver,the research of the dynamic compaction system of materials and compaction equipment including tamper and vibrator is needed.In the system,the reaction force generated by the vibrating tamper will impact screed.A periodic rectangular wave for the impact was presented and a dynamic model of the compaction system under the action of shock and vibration excitation was established.The effects of different vibration frequency and vibration frequency on the dynamic mechanical properties of the screed were analyzed.At the same time,the coupling effect of vibration and the vibration were calculated.Then,based on the combination of the vibration theory and the mathematical model,frequency characteristic of the paving density was discussed.Test and simulation results show that,the maximum response peak of screed is at the resonance frequency,but the response peak above the resonant frequency section is reduced by 23%comparing with the maximum,obtaining higher paving density and smooth operation of screed.Further more,compaction effect of tamper is greater than the vibrator.There are three main frequency components acting on screed with the action of tamper and vibrator,these excitations can be adapted to the complex components with different natural frequencies,which may provide the possibility of multi resonance during paving compaction.Therefore,when studying the vibration performance of screed to paving mixture,not only to consider the main resonance of the vibration frequency close to the natural frequency of material,but also should pay attention to the impact of tamper and the coupling effect of them to compacting paving.Results of the experiment can provide the basis for the selection of vibration parameters of the paver screed.