摘要
柱承式立筒仓广泛应用于国家粮食储备,不同储粮工况对其结构动力特性影响显著.为揭示粮食散体对柱承式立筒仓动力特性的影响规律,结合某实际柱承式立筒仓设计制作了缩尺比例为1/25的有机玻璃筒仓模型,在空仓、半仓、3/4仓和满仓4种储粮状态下,进行了振动台模态试验、有限元数值分析和自振频率理论计算.结果表明:不同储粮工况对柱承式立筒仓试验模型的固有频率影响显著,随储粮状态变化,固有频率减小幅度较大,应在结构设计中加以考虑;空仓状态下阻尼比最小,满仓状态比空仓增大42.65％,仓内原有储粮越多,阻尼比增值越大,减震耗能效果越明显;有限元模型一阶固有频率与试验值平均误差为5.1％,所建有限元模型较为合理,为结构动力响应分析及结构设计提供一种合理的数值模拟方法;简化的三质点串联多自由度的弹性动力模型较为准确计算柱承式立筒仓在4种储粮工况下的固有频率,试验值与理论值平均误差为5.6％.研究结果可为柱承式立筒仓结构动力特性计算提供参考,为其抗震性能设计提供理论基础和试验依据.
Abstract
Vertical silo is a type of container widely used in industrial and agricultural storage,transportation,and grain storage.According to its supporting structure,it can be divided into column supported and cylindrical supported types.As a modern grain storage warehouse type,column supported vertical silos have a small footprint,large storage capacity,and complete grain receiving,distribution,storage,cleaning,weighing,and automatic control functions.Different storage conditions have a significant impact on the dynamic characteristics of column supported vertical silos.To reveal the influence of grain dispersion on the dynamic characteristics of column supported vertical silos,an organic glass silo model with a scale ratio of 1∶25 was designed and made based on an actual column supported vertical silo design.Vibration table modal tests,finite element numerical analysis,and natural frequency theoretical calculations were conducted under four storage states:empty,half,three-quarters,and full.The research results indicate that different grain storage conditions have a significant impact on the natural frequency of the column supported vertical silo test model.As the grain storage state changes,the natural frequency decreases significantly,and should be considered in structural design;The damping ratio is the smallest in an empty warehouse state,and it increases by 42.65％in a full warehouse state compared to an empty warehouse state.The more existing grain is stored in the warehouse,the greater the increase in damping ratio and the more obvious the shock absorption and energy consumption effect;There is a significant difference between the torsional stiffness of the finite element model and the first two translational stiffness.Compared with the first two periods,the natural frequency of the third order of empty,half,three-quarters and full grain storage conditions increased by 27.2％,37.27％,39.93％and 40.09％respectively;The average error between the first-order natural frequency of the finite element model and the experimental value is 5.1％.The constructed finite element model is relatively reasonable,providing a reasonable numerical simulation method for structural dynamic response analysis and structural design;The simplified three particle series multi degree of freedom elastic dynamic model accurately calculates the natural frequencies of column supported vertical silos under four storage conditions,with an average error of 5.6％between experimental and theoretical values.This study can provide reference for the calculation of dynamic characteristics of column supported vertical silo structures,and provide theoretical basis and experimental basis for their seismic performance design.
基金项目
河南省重点实验室开放基金项目(2021KF-B07)
河南省科技攻关计划项目(242102110352)
河南省科技攻关项目(242102110350)
国家科技期刊平台
NSTL
万方数据