In order to reduce the fatigue damage detection error and improve the recall rate of fatigue damage data, this paper proposes a detection method based on acoustic signal acquisition for fatigue damage of nano ceramic coated rail. Firstly, the long-term fatigue behaviour of nano ceramic coated rail is analysed, and the typical damage evolution state of coating cracking at each stage is obtained. Then, based on the ultrasonic theory, the one-dimensional nonlinear elastic wave equation of rail vibration signal propagation process is constructed, and the modulated sidelobe signal of high-frequency ultrasonic is obtained. Finally, modulation parameters of rail fatigue damage are calculated by Fourier transform to determine the extent of fatigue damage. The experiment shows that the maximum error of the method for fatigue damage detection is only 0.5 mm, and the damage recall rate can reach 99.9%, indicating that the method improves the detection effect for fatigue damage.
In order to study the influence of carbobutadiene latex on the properties of concrete, this study studied the influence of carbobutadiene latex content on the microstructure of modified concrete. First of all, material selection and production of specimens, and then the physical properties, mechanical properties and microstructure of specimens were analysed to complete the effect of carboxybutene styrene latex content on the microstructure of modified concrete. The experimental results show that the modified concrete has better performance, minimum water reduction rate and higher bulk density when the content of carboxybutene styrene emulsion is 15%. By observing the microstructure, it is found that there are tree-trunk structure, latex film structure and interpenetrating network structure between latex film and concrete hydration products. At the same time, there are conical particles, which can greatly improve the performance of concrete.
