Study On The Effect Of Compound Thermal Environment In Cabin On Continuous Mental Workers

Cabins such as armored vehicle cabins,aircraft cockpits are often used in harsh natural environments,coupled with the narrow working space,numerous equipment,and no effective environmental control measures,resulting in a variety of harmful environments such as high temperature and humidity,noise and vibration.The combined effects of complex and harsh environmental factors,narrow and closed working spaces,and psychological and physiological stress will exhaust cabin crews physically and mentally,leading to a decrease in work efficiency.Therefore,cabin environment control is very important.Firstly,this paper summarized the influence mechanism of thermal environment,noise environment and vibration environment on human’s physiological function and mental state respectively.According to the existing work efficiency evaluation methods,a comprehensive evaluation index of mental work state comprehensively considering physiological,psychological and performance parameters was proposed.Based on these,a mechanism model of the compound thermal environment affecting the state of mental work was constructed.Then,a human experiment on mental workers under compound thermal conditions was carried out in a simulated climatic cabin.The subjects were 13 healthy male college students,aged 21.6±1.497 years old,height174.1±3.936 cm,weight 60.8±3.709 kg.The orthogonal test method was adopted in the rest.The operating temperature level of the test was 26℃、33℃、37℃,the noise level was 50 d B、70d B、85d B,and the vibration level was 10Hz、12Hz 、14Hz.The subject continued to work in the cabin for 2h.The task were 10 neurobehavioral tests,and the test task was applied as a mental work load and as a performance evaluation.Psychological parameters measured in the test include:work enthusiasm,total mood disturbance(TMD),and work fatigue.The physiological parameters measured in the test include: blood pressure,heart rate,eardrum temperature,blood oxygen saturation,grip strength,back strength,and average hearing threshold.Finally,through the analysis of the experimental data,the changes of the physiological parameters,psychological parameters and performance parameters of the mental workers with the working time under different working conditions were given.The main research results are as follows:(1)Excel and DPS software were used to carry out range analysis and variance analysis on the experimental data,and five measured parameters were extracted which were significantly affected by environmental factors: eardrum temperature,heart rate,oxygen saturation,work enthusiasm and neurobehavioral ability index.SPSS software was used to conduct factor analysis on the test data of these five extracted parameters,and two common factors,physiological and psychological factors and performance factors,were extracted,and the comprehensive evaluation index P of mental work state was obtained.(2)A multiple linear regression method was used to construct a mathematical model between cabin operating temperature and mental work status.After mathematical tests,the regression model is statistically significant.According to the comprehensive evaluation index,the mental work state of each experiment was divided into three grades:normal,basically normal and slightly decreased.K-means clustering analysis was used to obtain the clustering centers of the three grades.The operating temperature thresholds for the three types of mental work were calculated to be 26.7℃ and 34.2℃,respectively.(3)After the model verification test,it is found that the mental work state prediction model constructed by the experimental research in this article has a certain predictive effect,and the standard GJB 898A-2004 "General Medical Requirements and Evaluations for thermal environment of working room Workroom" is applicable to cabin mental workers in the compound thermal environment in this paper.