The Research On Interactive Influence And Coordination Deformation Of Embedded Strain Sensor And Asphalt Mixture

In recent years,sensor testing technology has been widely used in asphalt pavement engineering to monitor the mechanical response state of different positions inside the asphalt pavement structure in real time.Due to the large modulus difference between the embedded strain sensor and the asphalt mixture,it is easy to produce interactive influence and deformation is not coordinated,which affects the measurement accuracy and durability of the sensor.Therefore,it is particularly important to study the cooperative working mechanism between the sensor and asphalt mixture,so as to improve the service performance of the sensor in asphalt pavement.Through finite element simulation and laboratory test,this paper studies the interaction,coordinated deformation and influence range of embedded strain sensor and asphalt mixture.The numerical model of the asphalt mixture beam specimen embedded with strain sensor under four-point bending loading was established by using ABAQUS finite element software.By analyzing the mechanical response characteristics of the sensor and the asphalt mixture,it was found that the stress concentration occurred in the force measuring rod of the sensor and the asphalt mixture in contact with the sensor flange.The stress concentration coefficient is used to characterize the stress concentration degree of the sensor and the asphalt mixture,and the stress concentration degree of the sensor is greater than that of the asphalt mixture.The stress concentration of the sensor and the asphalt mixture is less affected by the load,but is greatly affected by the length of the sensor measuring rod and the sensor modulus.With the increase of the length of the sensor measuring rod and the sensor modulus,the stress concentration degree of the sensor and the asphalt mixture increases.Through the four-point bending laboratory test,the relationship between the measured strain of the sensor,the theoretical calculated strain and the real strain was compared and analyzed.The effectiveness of the measured strain of the sensor in asphalt mixture was verified,and the calibration formula between the measured strain of the sensor and the real strain was fitted.Based on the asphalt mixture of connection with sensor of strain changes,is proposed to coordinate deformation coefficient evaluation sensor and coordinate deformation of asphalt mixture performance,and analyzes the load size and load factors such as rod length and sensor modulus on the sensor and coordinate deformation of asphalt mixture performance and influencing factors of the influence of sensitivity;The results show that the coordinated deformation performance of the sensor and the asphalt mixture increases with the increase of the load and the length of the load rod,but decreases with the increase of the sensor modulus.The sensitivity of the influencing factors is sorted as follows:the length of the force rod>sensor modulus>load.By analyzing the change of stress field of asphalt mixture beam specimen after embedding sensor,and taking the stress difference rate of beam specimen as the evaluation index,the method of defining the influence range of the sensor on asphalt mixture was proposed.The influence of the sensor modulus,the length of the force rod and the diameter of the force rod on the influence range of the sensor is analyzed.The influence degree of each factor is sorted as follows:the sensor modulus>the length of the force rod>the diameter of the force rod,and the prediction formula of the influence range of the sensor on the asphalt mixture is established.Based on the influence range of the sensor on asphalt mixture,a modulus transition zone was established to improve the stress concentration phenomenon of the sensor in asphalt mixture.The results show that the stress concentration degree of the embedded sensor decreases obviously with the increase of the modulus transition zone modulus.The stress of asphalt mixture decreases slightly with the increase of modulus transition zone modulus.The study reveals the interaction and coordinated deformation mechanism between the embedded strain sensor and asphalt mixture,which is helpful to improve the measurement accuracy and durability of the embedded strain sensor in asphalt mixture.