Measurement Of Impact Dynamics Characteristic For The Drill Based On Fiber Bragg Grating Sensor

In recent years, with the high-accuracy development of detection technology inlarge-scale structure system such as aviation, aerospace, oil, civil, marine engineeringand so on, the dynamics problems are increasingly complex. Therefore, high qualitydynamic testing and analysis must be taken to ensure the project safety and economicrationality. The traditional electromagnetic sensing technology is far from meeting therequirements of high precision. As a new sensing technology, fiber grating sensingtechnology has many advantages such as high precision, light weight, small volume,and anti-interference capability that electromagnetic sensing technology can not reach,and is used widely in engineering.Improper impact power and quality may cause the structural instable when the impactdrill pipe working, and it also cause the cost wasting. Meanwhile, the process of theimpact is also accompanied by vibration, if the vibration frequency reach or close to thenatural frequency of the drill pipe, it might resonate, and it leads to the results that thesystem can not work properly, or even causes damage of structure and injury of the life.Therefore, when the drilling system is designed, especially in the high requirements ofpower consumption and quality of engineering (such as aerospace engineering), it isnecessary to analyze and test the drill dynamic characteristics.The impact dynamics characteristic of drill pipe is theoretically analyzed in this paper.Under the guidance of ANSYS finite element simulation’s results, the natural frequencyand stress wave transmission characteristics of the drill pipe is measured using the fiberBragg grating sensors. The main works of this paper include the following aspects:1. In this thesis, the characteristics and application of fiber Bragg grating sensor arestudied systematically. And the research status of impact dynamics parametermeasurement techniques is sketched, as well as the advantages and disadvantages ofdifferent detecting methods.2. The wave dynamics characteristics and the impact vibration characteristics of thedrill pipe are discussed in theory, the reflection and transmission of stress wave indifferent sections are analyzed, and the impact mechanism model is established. Usingfiber Bragg grating to detect the impact dynamics characteristics parameters of drill pipeis proposed.3. Using ANSYS finite element software to analyze the mode and non-lineardynamics simulation of the drill pipe. The obtained result natural frequency from the first to the fifth order respectively are537.94Hz,583.55Hz,1599.50Hz,1608.50Hzand2712.00Hz. Using different impact velocity to impact the drill pipe in axial, thestress schedules in different nodes and stress contours at different time are obtained.4. Detecting system of dynamic parameter in impact of drill pipe based on fiberBragg grating sensor is designed. The first five natural frequencies (532.99Hz,625.4Hz,1593.80Hz,1728.30Hz and2642.44Hz) of the drill rig are obtained byhammering method. The stress wave transmission characteristic is monitored by singleimpact under different initial velocity, and the strain schedules of the detecting nodesare drew。By comparing the experimental and simulation results, it is verified the feasibility ofthis method. This study will provide a new method for vibrating measurement ofengineering structures and mechanical systems.