Study On Infrared Temperature Field Characteristics Of Granite Under Uniaxial Compression After Different Water Temperature Soaking

Aiming at the problem of low-pressure detection in high temperature and high temperature environment,Based on the natural drying treatment,50? water temperature bubble and 100? water temperature soaking the granite specimen as the experimental object,the infrared test under uniaxial compression test,Respectively,from the discrete parameters(rang and variance),shape parameters(skewness and kurtosis)and smooth uniformity(entropy and characteristic roughness)of the three angles of the system analysis.And compare and identificate the same parameter of different water soaked specimens,the "characterization" of each parameter is analyzed by correlation coefficient method.The Hill diagram method is used to determine the threshold value and extract the high temperature and low temperature anomaly points.The evolution of the temperature field and the infrared precursor information.The main research results are as follows:(1)The stress-strain curves of the specimens after different water temperature immersion are similar,which are divided into four stages: compaction,elasticity,plasticity and post-peak.When soaking water temperature at 50 degrees water temperature,the peak stress is the maximum,and the peak stress is minimum when the water temperature is 100 degrees,while the maximum strain is not significant with the water temperature.(2)In the aspect of infrared precursory performance,the maximum infrared temperature,skewness and kurtosis performance are better,and with the increase of water temperature,the maximum infrared temperature and the extreme abnormalities are obviously significant;Natural dry and 50 ? water temperature of the sample variance and entropy will produce significant anomalies,and 100 ? water temperature of the specimen no obvious anomalies;abnormal performance is the worst performance roughness.(3)Comparison of the same parameters for different water temperature test specimens,The natural dry specimen is smallest,the average and maximum infrared temperature values are the smaller,which is convenient to identify.100 ? water temperature test specimen skew and kurtosis is the largest,easy to identify,There are no obvious demarcation characteristics of the residual parameters,the variance,the entropy and the characteristic roughness.(4)Analysis of the effect of "portraying" the change of infrared temperature field in different water temperature test pieces:The correlation coefficient of natural dry specimen entropy is higher and stable,and "characterization" is better;For the specimen with 100 ? water temperature,the correlation coefficient of variance,kurtosis and characteristic roughness is high,and the ability of portability is better;Skew the 50 ? water temperature and 100 ? water immersion after the ability to describe the image are better,and the poor "portraying" ability is not ideal.(5)Using the Hill diagram method to set the threshold value to analyze the change of the infrared temperature anomaly point by the extreme value theory:In the high temperature anomaly point,the natural drying and 100 ? water temperature of the specimen has similarity,in the early loading are relatively calm,to the plastic and the peak stage after the abnormal point of the rapid increase in the curve beating abnormalities,and 50 ? water temperature of the specimen law not obvious;In the case of low temperature anomalies,there was no obvious law of the variation curve of all the samples at low temperature,which indicated that this method was not ideal for low temperature anomaly extraction.