A Novel Setup For Detecting Hysteresis Loop Of Ferromagnetic Material Based On Labview

Ferromagnetic material has a specific performance, so it can be widely applied to areas of modern technology and national defense (such as industry, transport, communications, electrical, plumbing, railways, automobiles, bridges, aviation, strong magnetic fields, etc.) With the social development and constant scientific progress, ferromagnetic materials have become indispensable in our lives. Due to the unique character of ferromagnetic materials, they play an important role in various fields. However, the application, safety and specificity of these materials and equipment must be characterized by understanding the essential characteristics of the ferromagnetic material. Even the same piece of material can result in differences in the nature of its own due to extra external stress, external bias field and other reasons. Therefore, when we use and design any kind of ferromagnetic materials, it is necessary to detect its internal nature at first, while the magnetization curve and hysteresis loop is a good form of expressing its nature. Therefore, drawing out the different magnetization curves of ferromagnetic materials and magnetic hysteresis is an important basis for employing and designing ferromagnetic materials.A large number of scholars have proved out that magnetization curve and hysteresis loop are sensitively dependent on the structure of magnetic materials and their microstructure, such as grain size, grain orientation alignment, internal stress distribution, mechanical processing conditions heat treatment. Different conditions will lead to magnetization curve and hysteresis loop with different shape, on behalf of the above we can see that the sizes of magnetic parameters (such as remanence, coercivity, permeability, etc.) are not quite the same. The theoretical basis for this device is reliable: using ferromagnetic material magnetization curve and hysteresis loop induced by electromagnetic fields under different conditions, magnetic parameters reflected by the magnetization curve and magnetic hysteresis loop can be employed to determine internal magnetic properties of ferromagnetic materials. Pulsed power technology can effectively improve the measurement accuracy and enhance the detection depth. Using Labview acquisition will greatly enhance the collection speed. The equipment and samples in experiment are easy to obtain and the whole experiment is with high feasibility. The approach using this device is feasible: pulsed power technology is applied to induce the magnetization curves and magnetic hysteresis loop of ferromagnetic materials, according to the magnetic parameters reflected from magnetization curve and hysteresis loop, the internal magnetic characteristics of ferromagnetic materials can be well characterized, which provide great application value of ferromagnetic materials.The measurement equipment of this device is composed of several following parts: the piece of producing pulsed electromagnetic field, the piece of detection probe and the pieces of data collection and processing respectively. Of which the pulsed electromagnetic field is obtained through the effect of discharge of charge and discharge capacitor to discharge coil, sensor signal introduced by detection probe was first imputed to high-speed computer with Labview to collect system DAQ, then by data processing of Labview in computer, the magnetization curve and magnetic hysteresis loops of the whole process of technical magnetization, as well as various magnetic parameters can be obtained. The approach in this device is a kind of relative measurement. This dissertation aims to introduce a fast and accurate device with deep detection depth to detect magnetization hysteresis loop and magnetization curve of ferromagnetic material. This dissertation is mainly composed of the following aspects:( 1 ) We outline the principles and application of ferromagnetism and ferromagnetic material, also introduce at the same time the current situation and existing problems in the process of detecting initial magnetization curve and magnetic hysteresis loop of ferromagnetic materials in our country and abroad. We present in this thesis the advantage of new device of detecting magnetization curve and magnetic hysteresis loop of ferromagnetic materials: using Labview graphic platform to collect and process data can achieve the automatic mapping of magnetization curve and hysteresis loop, so as to further improve the testing efficiency; Pulse current is employed to serve as the excitation current, the probing depth is greatly strengthened, and it can bring out various properties of internal part of ferromagnetic materials, exclude the interference, so that the detection results are more accurate.(2)The basic theory of designed device is made a systematic summary in this chapter. The content includes: basic characteristics of the curve; magnetization process and hysteresis loop; basic concepts of Labview.(3)Introduction of the basic structure and working measurement of novel device for detecting magnetization hysteresis loop of ferromagnetic materials based on Labview. The device is generally divided into three parts: detection probe part; DAQ data collection part; computer data processing. The sensor signal of excitation coil is a kind of pulse signal provided by the charge and discharge capacitor, so as to generate excitation magnetic field of pulse in coil, the pulse magnetic signal from coil can be transformed to electrical signal output by probe of introduction coil; DAQ collection system can be used to acquire excitation signal and sensor signal, then the collected data will be imputed into computer by Labview collection card, with the aid of Labview, the specific data can be processed.(4)Detailed description of the basic structure of measurement probe: the device used is the most widely used, a probe with simple structure is composed of the U-core wounded around with excitation coil and the induction coil, this is also employed as economic and easy probe structure among the majority of experts focusing on internal properties of ferromagnetic material all over the world; the application of ferrite materials as a probe effectively avoided the phenomenon of vortex introduced by using probe made of amorphous alloys, and the magnetic permeability of ferrite material is poor, so under the circumstance of big power and high current, the probe itself is not easy to reach saturation, resulting in better permeability effect.(5)Introduction of specific collection mechanism of DAQ: 0 and 8 faucets have been employed to collect U introduction signal by using DAQ collection card, 5 and 13 faucets were employed to collect U excitation signal, the main purpose of this is to reduce the effect of two simultaneously collected signal as much as possible; difference collection is applied, and we introduced the difference between difference collection and same land collection, as well as the advantage of difference collection; the settings of all projects of DAQ are presented.(6)Computer data input and data processing: using Labview programming software, we achieve the interception of signal collection and the integration of induced voltage signal, as well as the XY mapping input from current value and voltage value after integration, drawing the whole procedure of magnetization hysteresis loop.(7)Measurement of magnetization curve: the comparison of collecting initial magnetization curves under different magnetic fields from one angle iron and initial magnetization curves collected from different angle irons. From these two sets of comparative test, we can conclude that our designed device based on Labview detecting magnetization hysteresis loop of ferromagnetic materials is able to finish the accurate measurement of initial magnetization curve under different magnetic fields and different materials.(8)Measurement of hysteresis loop: we introduce the method of collecting magnetization hysteresis loop and the removal of interference, as well as the specific method of adjusting image symmetry. The above practical experiment can prove that our designed device can effectively measure more accurate and integrate hysteresis loop.