基于磁通量法的空间网架结构无损应力检测的试验方法研究?

测试在役空间网架结构的轴力或应力是网架结构健康检测的核心内容之一,探究一种实用无损的应力检测方式对在役空间网架结构的健康状况进行合理的评估成为当前工程亟待解决的问题。磁通量法在桥梁索力检测的应用比较成熟,但没有应用于空间结构的杆件应力测试方面主要是由于网架结构杆件在长度、受力性质及约束的影响而使其杆件轴力的测试尚处于研究阶段。据此采用磁通量法对网架结构杆件轴力进行了试验研究。选取了可能影响轴力测试结果的感应线圈绕线匝数、激励线圈绕线匝数、激励电压、荷载工况四个因素开展了一系列的试验研究。结果表明:传感器的绕线匝数、激励电压都会直接影响到电磁感应响度的大小,实际工程中必须选择合适的绕线匝数和激励电压。磁通量传感器在套入杆件后对不同的荷载工况表现出了良好的敏感性,将其运用于杆件的轴力检测是可行的。

Study on the Test Method of Nondestructive Stress Test of Space Truss Structure by Magnetic Flux Method

Measuring the axial force or stress of the long-span truss structure is one of the core con?tents of the health monitoring of the truss structure. Exploring a non-destructive health monitoringmethod to assess the health of the truss structure in a reasonable assessment of the current project is tobe solved. The application of magnetic flux method in bridge cable force monitoring is relatively ma?ture,but it is still in the research stage when it is applied to obtain bar axial force of truss structures.Because of the obvious differences in the length,material properties,mechanical properties and con?straints of the lattice structure,it is necessary to carry out further experimental studies on the factorsthat may affect the test results to determine whether it is feasible. In this paper,the magnetic fluxmethod is used to study the bar axial force of the truss structure. A series of experimental studies werecarried out on four factors:the winding turns of the induction coil,the winding turns of the excitationcoil,the excitation voltage and the load case,which could affect the test results. The results show thatthe winding number and the excitation voltage of the sensor will directly affect the loudness of the elec?tromagnetic induction,and the number of turns and the excitation voltage must be selected in a certainengineering project. The magnetic flux sensor exhibits good sensitivity to the different load conditionsafter the bar is inserted,and it is feasible to apply it to axial force measurement of the bar.