Understanding the vibration characteristics of a seated human body is critical for evaluation and improvement of ride comfort of various passenger vehicles. There have been very little publications about the vibration...Understanding the vibration characteristics of a seated human body is critical for evaluation and improvement of ride comfort of various passenger vehicles. There have been very little publications about the vibration characteristics of a seated Chinese human body. By using wide-band white noise excitations and a homemade seat sensor, vertical vibration tests were carried out on 28 volunteers. Apparent masses were obtained for each volunteer at a frequency range of 1-20 Hz for various excitation le-vels. A biodynamic model, which has two degrees of freedom in parallel and includes a frame mass, was chosen to describe the vertical vibration characteristics of the seated human body. The model parameters were identified by means of a Gauss-Newton method with an error function defined in terms of both real and imaginary parts of the apparent mass against frequency. Based on the averaged data of the mass-normalized apparent mass from experiments, the model parameters and corresponding modal parameters were obtained for seated Chinese people at ages of 20-25 with standard weight. The apparent masses predicted by the biodynamic model with identified parameters agree very well with those obtained from experiments. Statistical analysis demonstrates the influence of volunteer’s height and weight on the model parameters for a seated human body.展开更多
This paper presents an energy absorber made of composite tubes and metal connectors.The composite tube is filled with foam.When it is subjected to impact,the composite tube is axially compressed and collapsed.The tube...This paper presents an energy absorber made of composite tubes and metal connectors.The composite tube is filled with foam.When it is subjected to impact,the composite tube is axially compressed and collapsed.The tube-wall folds inward and squeeze the foam.There is no fragment overflowing after the composite tube was collapsed and the fragments fills in the tube to increase the energy absorption.The impact energy is mainly absorbed by fiber breakage,delamination and foam squash.A dynamic impact test was carried out to explore the energy absorption performance of the absorber.The results proved that it can reduce the initial peak load and increase the specific energy absorption,which is suitable for lightweight and crashworthy structure design.To investigate the application of the absorber to the helicopter crashworthy seats,a non-linear five-degree-of-freedom model of the occupant and seat is established.Themodel includes five lumped masseswhich represent the head,viscera,upper torso,pelvis,and seat,respectively.The biodynamic response of the model under impact is simulated,and the results show the positive effect of the absorber on the shock mitigation.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50675110)the Research Foundation of State Key Laboratory of Automotive Safety and Energy (Grant No. ZZ080082)
文摘Understanding the vibration characteristics of a seated human body is critical for evaluation and improvement of ride comfort of various passenger vehicles. There have been very little publications about the vibration characteristics of a seated Chinese human body. By using wide-band white noise excitations and a homemade seat sensor, vertical vibration tests were carried out on 28 volunteers. Apparent masses were obtained for each volunteer at a frequency range of 1-20 Hz for various excitation le-vels. A biodynamic model, which has two degrees of freedom in parallel and includes a frame mass, was chosen to describe the vertical vibration characteristics of the seated human body. The model parameters were identified by means of a Gauss-Newton method with an error function defined in terms of both real and imaginary parts of the apparent mass against frequency. Based on the averaged data of the mass-normalized apparent mass from experiments, the model parameters and corresponding modal parameters were obtained for seated Chinese people at ages of 20-25 with standard weight. The apparent masses predicted by the biodynamic model with identified parameters agree very well with those obtained from experiments. Statistical analysis demonstrates the influence of volunteer’s height and weight on the model parameters for a seated human body.
基金supported by the Natural Science Foundation of China(Grant No.12072199).
文摘This paper presents an energy absorber made of composite tubes and metal connectors.The composite tube is filled with foam.When it is subjected to impact,the composite tube is axially compressed and collapsed.The tube-wall folds inward and squeeze the foam.There is no fragment overflowing after the composite tube was collapsed and the fragments fills in the tube to increase the energy absorption.The impact energy is mainly absorbed by fiber breakage,delamination and foam squash.A dynamic impact test was carried out to explore the energy absorption performance of the absorber.The results proved that it can reduce the initial peak load and increase the specific energy absorption,which is suitable for lightweight and crashworthy structure design.To investigate the application of the absorber to the helicopter crashworthy seats,a non-linear five-degree-of-freedom model of the occupant and seat is established.Themodel includes five lumped masseswhich represent the head,viscera,upper torso,pelvis,and seat,respectively.The biodynamic response of the model under impact is simulated,and the results show the positive effect of the absorber on the shock mitigation.
