Detection For Impact Energy Based On Fiber Bragg Grating

The impact machinery is a class of engineering equipment which is driven by the energy generated with impact to destroy the rock.It is widely used in drilling,exploration and other industrial and agricultural construction for its high efficiency,fast drilling and easy control.The impact hammer is the key components of impact machinery,whose performance directly affects the performance of the impact machine.The impact energy is a direct evaluation index of the performance of the impact hammer,which can be measured and analyzed with scientific testing methods.It not only helps the user to choose products suitable for the application place,reduce the purchase cost,it is also necessary to manufactures to improve product design,enhance product performance,improve market competitiveness.Stress wave technique is the most commonly method used for the impact energy detecting.As far as the impact environment is concerned,the traditional electrical sensor-strain gauge is highly susceptible to electromagnetic interference and humid air,which make the measurement error.Fiber Bragg grating is a new type of optical sensor,which has many advantages such as anti-electromagnetic interference,corrosion resistance,small size and so on.It is widely used in various engineering fields.The research of fiber Bragg grating for dynamic strain detection is developing rapidly.The main contents of this paper are as follows:The impact energy detecting system based on the stress wave technique is determined based on the analysis of the advantages and disadvantages of the testing methods for impact energy at home and abroad,while a method to detect the impact energy using the fiber Bragg grating as the sensing element is presented.At the same time,the present situation,principle and demodulation method of fiber Bragg grating for impact strain detection are briefly introduced.The theory of one-dimensional wave dynamics for the impact system is analyzed theoretically.The reflection characteristics of the stress wave at different end faces are discussed.The stress wave waveform function of the two rod coaxially impact is established while the energy of the incident stress wave is analyzed.The dynamic simulation of two rod coaxially impact using ANSYS finite element software are conducted,the incident stress wave generated by the coaxial impact of two rods under different wave resistance ratios are obtained,and then the simulation results are compared with the theoretical analysis.The impact energy detection system based on fiber Bragg grating was built and the impact energy was detected.The curves of the incident strain pulse is obtained which is used to derive the impact energy based on the trapezoidal integral formula,and then the impact energy is compared with the kinetic energy of the impact rod.The feasibility of using fiber Bragg grating to detect impact energy is verified based on comparing the experimental results and simulation results,which provides a new method for the impact energy detection.