材料密度、外界振动强度等的定量关系,还得出了NOPD能量耗散率在阻尼器内部的分布情况。本文所得到的理论模型与仿真及实验规律具有较好的一致性,为理解NOPD的耗能机理,指导其在不同工况下的参数优化设计,奠定了一定的理论基础。
6结论
本文使用离散单元方法初步研究了NOPD内部颗粒在振动激励下的对流运动。在此基础上引入颗粒流一般本构关系,并使用普朗特混合长度理论对其修正,最终建立NOPD能量耗散的理论模型。该模型不仅得到了NOPD能量耗散率随颗粒参数以及振动强度的一般规律,还明确了阻尼器内部不同区域耗能功率的差异。研究结果表明,靠近阻尼器腔壁的颗粒较中心位置处的颗粒消耗更多的能量;阻尼器底部的颗粒较表层颗粒有更高的能量耗散率。通过对NOPD在不同振动条件下的能量耗散功率进行测试,验证了本文模型的正确性。该模型的提出不仅能够进一步揭示NOPD的耗能机理,也为NOPD的参数设计提供了一定的理论依据,并为提高NOPD的减振效果提供了一种新的途径。
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