甘蔗切割器系统轴裂纹识别分析  

An analysis of crack identification in the shaft of sugarcane cutter system

作　　者：魏道高[1] 胡美玲[1] 马倩[1] 区颖刚[2] 

机构地区：[1]合肥工业大学机械与汽车工程学院,安徽合肥230009 [2]华南农业大学南方农业机械与装备关键技术省部共建教育部重点实验室,广东广州510642

出　　处：《华南农业大学学报》2014年第3期105-110,共6页Journal of South China Agricultural University

基　　金：省部共建教育部重点实验室开放基金资助项目(KF200707);国家自然科学基金(51050002;51375130)

摘　　要：【目的】从甘蔗切割器系统多种非线性因素作用下的振动特性中获得识别轴裂纹的信息.【方法】将切割器简化成铅垂悬臂转子-支承系统,将斜裂纹设置在轴与盘身连接处附近,只考虑裂纹与切割力2种非线性因素建立了该系统的3自由度动力学方程.基于该模型,选用开斜裂纹刚度计算模型,对含斜裂纹的甘蔗切割器动力特性进行数值仿真.【结果和结论】当Ω=500 r·min-1系统在无裂纹而仅有非线性切割力作用下,横向振动出现了工频和组合频率响应;相同工况时,系统在含裂纹和非线性切割力双因素作用下,横向振动出现了工频和组合频率,但新增加了二倍频响应,且随裂纹深度增加二倍频响应幅值增加.由此可从2种非线性因素中获得识别轴裂纹信息.扭转振动则在有裂纹时比无裂纹情况下增加了工频成分.[Objective]To get identification information of crack on the shaft from vibration characteristics of the system under the condition of various nonlinear factors .[Method] The cutter was simplified to a vertical over-hung rotor-bearing system , and the slant crack was set near the junction between the shaft and the disk , taking into consideration two nonlinear factors .The slant crack and the nonlinear cutting force, three degrees of freedom dynamic equations of the system were founded .Based on this model , a stiffness calculation model of opening slant crack was chosen .The dynamic characteristics of the slant cracked cutter were investigated by numerical simulation .[Result and conclusion] The results showed that whenΩ=500 r· min-1 system was only under the condition of nonlinear cutting force without crack , working frequency and combined frequencies appeared in frequency responses of transverse vibration .In the same working condition , when the system was under the condition of both crack and nonlinear cutting force, the system had working frequency , combined frequencies and also a newly added second harmonic frequency which were frequency responses .In addition , with the increase of the crack depth , the ampli-tude of the second harmonic frequency was also increasing .Therefore , the identification signal of crack can be attained from two nonlinear factors .Besides , in torsional vibration , working frequency newly ap-peared because of the crack .

关 键 词：甘蔗 切割器 斜裂纹 非线性切割力 

分 类 号：S225[农业科学—农业机械化工程]