Experimental Study On The Seat Vertical Vibration Of Engineering Vehicle And Its Influence On The Human Body

As one of the most important construction equipment in the modernized civilization construction of a country,engineering vehicles play a significant role in the development of national economy.Compared with conventional road traffic vehicles,engineering vehicles have a poorer working environment and more complex road conditions.During working,the impact and vibration from the environment may cause varying degrees of damage to the drivers.The major source of vibration is from the vertical vibration of the engineering vehicles,which can cause both physical and psychological discomfort to the drivers,and thus may affect the working efficiency and safety.For long-term drivers of the engineering vehicles,the vibration will raise harm to the spine and other parts of the drivers,which even can seriously affecting one's health.This thesis combines the National Natural Science Foundation of China “Multi-dimensional Nonlinear Vibration Isolation Technology of Engineering Machinery Seat System” to study the influence of vertical vibration on the human body in designing the engineering vehicle seats and reducing vibration.According to the international standard ISO2631 on the human body to withstand the results of vibration research and evaluation,as well as the actual working conditions of the vehicle,the establishment of engineering vehicle vibration evaluation system and human injury standards is built.According to the evaluation of seat vibration of international standard ISO 7096:2000 Earth-moving machinery – Laboratory evaluation of operator seat vibration,China's standardization committee issued GB/T 8419-2007 and GB/T 18707.1-2002 Laboratory method on Machinery Vibration evaluation of vehicle seat and other related standards,a vibration test platform is designed and manufactured for vibration experiments on the engineering vehicle suspension seat in laboratory environment.Several vertical vibration dynamic models of the human body are established,and the vertical vibration characteristics of the sitting body are investigated.According to the force on the human body,two degree of freedom(DOF)vertical vibration model is established as well as 3-DOF dynamics model and 4-DOF dynamics model.The mathematical expression of the apparent mass,the seat transfer function and the driving point impedance of the human body model are deduced.The dynamic characteristics of the vertical vibration of sitting body can be studied and analyzed.The developed vertical test platform with engineering vehicle suspension seat is used for vibration experiments with a simulated working environment.According to the international standard ISO 7096: 2000 and the national standard GB/T 8419-2007 on the various types of vehicle seat input vibration classification and regulations,several different spectral types of vertical excitation signals are applied to the seat to simulation the corresponding engineering vehicle types and working conditions.By collecting acceleration signals from the head and wrist of the ES-2 type human body model,the response of various parts of model can be detected.Then,the vibration comfort of human body under various conditions can be evaluated with use of the vibration evaluation system.The thesis carries experimental work on the vertical vibration of engineering vehicle seat and its impact on the human body,and provides a reference for the design and evaluation of vehicle comfort.