Study On The Evaluation And Optimization Of High-speed Railways Seat Comfort Based On Interface Pressure

As one of the main facilities in high-speed trains,seats have the longest contact time with passengers,which can directly affect the riding experience.With the expansion of Chinese railway network,longterm sitting is usually happened to train passengers.In this case,fatigue is likely to occur,resulting in significant degradation in comfort ratings.In this case,the improvement of seat comfort has become a key scientific and engineering issue in railway development.Therefore,this study aimed to reveal the comfort degradation mechanism and carry out optimization of seat comfort based on interface pressure.The main work is as follows:(1)Long-term sitting tests were conducted on the China Railway Highspeed Train running on the Shanghai-Kunming line.The subjective and objective data were obtained from several participants,with the sampling frequency of 5 Hz for interface pressure matrices and 10 minutes for overall and local subjective comfort.(2)Random forest regressor was used to establish evaluation model for overall comfort and eight regional comforts of high-speed railway seats,and the feature weights were calculated.Results showed that the peak pressure,mean pressure and contact area ratio of upper thigh have the best comfort predictive ability.More sample labels were obtained by using the evaluation model,and the interval of subjective data was shortened from10 minutes to 3 seconds.(3)The relationship between regional and overall comfort,subjective and objective variables was analyzed,and the comfort degradation mechanism of high-speed railway passengers was revealed.Results showed that the overall comfort can be predicted by the comfort of shoulder,waist,and buttocks in most of time periods.In addition,the seat plays a different role in long-term and short-term sitting.In the first 20 minutes,the seat has a negative correction effect on the comfort degradation rate,then fatigue occurs after this,and comfort correction factor begins to turn positive after a short lag,which partially offsets the effect of fatigue.(4)The mechanical properties of the second-class seat cushion foam were tested.The human-chair finite element model was constructed and then verified.Finally,by combining the simulation results and the comfort evaluation model,the comfort of seats with 12 different parameter combinations was comprehensively evaluated.Results showed that the highest comfort is achieved when seat angle is set to 10° and foam B with slightly larger stiffness is used to defined cushion and backrest,which can effectively improve subjective comfort by more than 50%.