摘要
为解决预应力框架大型液压机的预紧状态检验问题,通过力学分析得到在拉杆端部进一步施加拉力的过程中拉杆相对拉力的变化规律,即拉杆相对拉力随拉杆端部所施加拉力的增加近似呈折线变化,并且螺母的连接刚度影响折线转折点附近的过渡曲线形态。据此提出一种拉杆预紧力的非缓解测量原理,同时从理论上证明拉杆预紧力测量精度对应变片贴片方向的不敏感性。基于NI公司的虚拟仪器平台LabVIEW开发了专用测试系统。用物理模型试验对非缓解测量原理和测试系统进行试验检验,试验结果证实测量原理的正确性和测试系统的可行性。研究工作为大型液压机预紧状态的检测提供实现手段,也为大型液压机整体性的故障诊断提供所必需的条件。
In order to get a solution for inspecting the pre-tightening state of pre-stressed frame heavy hydraulic press,the change law of the tension force in the tie rod with the pulling force at the end of the tie rod,which shows that the tension force curve is nearly a two-segment broken line with a curved transition caused by the insufficient connection stiffness of nut,is obtained by mechanics analysis.A measurement principle for obtaining the pre-tightening force of the tie rod without release of the tightening of tie rod is presented and the insensitivity of measurement precision to the stick-on orientation of the strain gauge is theoretically proved.A measurement system is developed on the virtual instrument platform,LabVIEW,of NI Company.Experiments are carried out to verify the correctness of the principle and the feasibility of the system by using a physical model.The research provides an implementation means for evaluating the pre-stress status of the pre-tightening state of heavy hydraulic press in service,as well as the necessary condition for malfunction diagnosis of the integrity of heavy hydraulic press.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第22期70-74,共5页
Journal of Mechanical Engineering
关键词
预应力
液压机
预紧力
非缓解测量
虚拟仪器
Pre-stress Hydraulic press Pre-tightening force Non-release measurement Virtual instrument
