Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface bet...Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface between human and seat, which can be obtained by simulation. But current simulation method focuses mainly on calculation itself other than combining it with posture prediction and cab packaging parameters, which cause it difficult to acquire accurate pressure calculation results without accurate posture of human body, and make it almost meaningless to design optimization. Therefore, a human body geometric model with posture change capability is built and linked up with Cascade Prediction Model（CPM）, which takes cab packaging parameters as inputs. A detailed finite element model of driver human body is constructed and used to conduct the driver-seat interaction simulation between human body and seat. Good accordance of pressure distribution is observed between simulation and test, which validates the simulation. In addition to the distribution pattern, curves on key sections are used to analyze the pressure and shear stress on the seat surface, as well as soft tissue stress inside human body. The simulation shows that the maximum stress of buttocks locates under the ischial tuberosity, and the maximum stress of trunk occurs near the scapula posterior and the lower waist. These are the places where fatigue usually occurs. The maximum pressure of seat appears at the driver-seat contact area corresponding to the driver＇s maximum skin tissue stress. In order to guide the seat design and cab packaging and study the influence of posture to pressure distribution, finite element models for different levels of cab packaging parameters are created by using CPM. The pressure distributions are calculated and their tendencies varying with cab packaging parameters are obtained. The method presented provides a new way to accurately simulate the interaction between driver human body and seat, and to guide the seat design and cab packaging so as to improve seating comfort.展开更多
Discomfort caused by long-term sitting decreases the passenger experience and may lead to musculoskeletal diseases, and this hasbecome one of the main problems for passengers of high-speed railways. However, the comfo...Discomfort caused by long-term sitting decreases the passenger experience and may lead to musculoskeletal diseases, and this hasbecome one of the main problems for passengers of high-speed railways. However, the comfort degradation mechanism during longtermsitting in high-speed railways is still unknown. This study aimed to reveal passengers’ sitting comfort degradation mechanismin high-speed railways. By carrying out long-term sitting tests on high-speed trains running on the Shanghai-Kunming line, the dynamicinterface pressure and subjective comfort including overall and regional comfort of seven participants were obtained.Machinelearning models and statistical analysis methods were combined for data analysis to reveal the effect of regional comfort and thecontribution of sitting duration during the process of sitting comfort degradation. The results show that overall comfort is most significantlyinfluenced by the comfort of the shoulders, waist and buttocks. The seats play different roles before and after 20 minutesduring long-term sitting and there is a lag between the fatigue occurring and being offset. Therefore, the structure of seats affectsoverall comfort by affecting important regional comfort, and a long-term sitting test is necessary for accurate seat assessment. Thecomfort degradation mechanism can be used to define standards for long-term sitting comfort or provide guidance for seat evaluation,and the design and evaluation plan mentioned in this article for second-class seats can be applied to other cases with limitedaccommodating space.展开更多
基金supported by 2011 Scientific Frontier and Interdiscipline Reformation Project of Jilin University,China(Grant No.450060445100)
文摘Test is one of methods to acquire human-seat pressure distribution in driving, with the deficiency of being uneasy to obtain the stress information of soft tissue inside human body and the sheer force of interface between human and seat, which can be obtained by simulation. But current simulation method focuses mainly on calculation itself other than combining it with posture prediction and cab packaging parameters, which cause it difficult to acquire accurate pressure calculation results without accurate posture of human body, and make it almost meaningless to design optimization. Therefore, a human body geometric model with posture change capability is built and linked up with Cascade Prediction Model（CPM）, which takes cab packaging parameters as inputs. A detailed finite element model of driver human body is constructed and used to conduct the driver-seat interaction simulation between human body and seat. Good accordance of pressure distribution is observed between simulation and test, which validates the simulation. In addition to the distribution pattern, curves on key sections are used to analyze the pressure and shear stress on the seat surface, as well as soft tissue stress inside human body. The simulation shows that the maximum stress of buttocks locates under the ischial tuberosity, and the maximum stress of trunk occurs near the scapula posterior and the lower waist. These are the places where fatigue usually occurs. The maximum pressure of seat appears at the driver-seat contact area corresponding to the driver＇s maximum skin tissue stress. In order to guide the seat design and cab packaging and study the influence of posture to pressure distribution, finite element models for different levels of cab packaging parameters are created by using CPM. The pressure distributions are calculated and their tendencies varying with cab packaging parameters are obtained. The method presented provides a new way to accurately simulate the interaction between driver human body and seat, and to guide the seat design and cab packaging so as to improve seating comfort.
基金the National Natural Science Foundation of China(Grant No.52075553)the Hunan Science Foundation for Distinguished Young Scholars of China(Grant No.2021JJ10059)the School Enterprise Cooperation Program of Central South University(Grant No.2021XQLH011).
文摘Discomfort caused by long-term sitting decreases the passenger experience and may lead to musculoskeletal diseases, and this hasbecome one of the main problems for passengers of high-speed railways. However, the comfort degradation mechanism during longtermsitting in high-speed railways is still unknown. This study aimed to reveal passengers’ sitting comfort degradation mechanismin high-speed railways. By carrying out long-term sitting tests on high-speed trains running on the Shanghai-Kunming line, the dynamicinterface pressure and subjective comfort including overall and regional comfort of seven participants were obtained.Machinelearning models and statistical analysis methods were combined for data analysis to reveal the effect of regional comfort and thecontribution of sitting duration during the process of sitting comfort degradation. The results show that overall comfort is most significantlyinfluenced by the comfort of the shoulders, waist and buttocks. The seats play different roles before and after 20 minutesduring long-term sitting and there is a lag between the fatigue occurring and being offset. Therefore, the structure of seats affectsoverall comfort by affecting important regional comfort, and a long-term sitting test is necessary for accurate seat assessment. Thecomfort degradation mechanism can be used to define standards for long-term sitting comfort or provide guidance for seat evaluation,and the design and evaluation plan mentioned in this article for second-class seats can be applied to other cases with limitedaccommodating space.
