The Research On Testing Methods Of Hybrid ? 50th Dummy Lumbar Spine's Mechanical Properties

Correctly assessing and ensuring the biological fidelity and mechanical properties of the dummy components are very important for the vehicle crash safety test.As the only connection supports between the pelvic and thoracic spine,the lumbar spine of the crash test dummy is closely related to the dynamic response of the dummy chest and pelvis.However,there is a lack of research on testing methods of Hybrid III 50th dummy lumbar spine 's mechanical properties in China at present.Aiming at this problem,this paper makes a systematic research on the testing methods of the mechanical properties of the dummy lumbar spine.The research is divided into two parts.First of all,the dummy lumbar spine static bending and dynamic impact test devices were established,and the effect of dummy lumbar spine rubber hardness on mechanical properties of lumbar spine was studied.Secondly,the effect of the rubber hardness of the dummy lumbar spine on the thorax calibration was studied by means of the thorax calibration test and the thorax calibration simulation.Based on the characteristics of the dummy lumbar spine in the crash test,the static bending test device for the dummy lumbar spine was designed and constructed.The test device has the advantages of simple operation and good repeatability,and solves the defects of large vibration of the existing lumbar static stretching device when the lumbar spine bends 29 degrees.Five dummy lumbar spine were tested for preliminarily evaluating the mechanical properties of the dummy lumbar spine under static bending.And the test results are stable and consistent.The acceleration curve of a mass production vehicle under frontal full impact was obtained by the method of experiment and simulation,and further obtaining the dynamic bending curve of the dummy lumbar spine in the sled test.Based on this curve,a dynamic impact bending test device for dummy lumbar spine was designed and constructed.The test device can reflect the dynamic characteristics of the lumbar spine in the sled test,with simple operation and good repeatability characteristics.The research on the effect of lumbar rubber hardness on the peak value of dynamic bending angle was carried out,the results show that there is a negative linear relationship between the hardness and the peak value of dynamic bending angle.It is indicated that when the rubber hardness increased 1 °,the peak value of lumbar bending angle decreased about 0.56°.The results of single factor analysis of variance(ANOVA)show that the hardness of the lumbar spine rubber has a significant effect on the peak value of the dynamic impact of the lumbar spine,which indicates that the dummy lumbar spine of different rubber hardness will further affect the results of the dummy's thorax calibration test.The effect of the rubber hardness of the dummy lumbar spine on the dummy thorax calibration were studied by combining the thorax calibration test and simulation.In the thorax calibration,it has a very similar chest compression-resistance force curve from the dummy which were assembled with the lumbar spine of HA80 and HA84 rubber hardness respectively,and the peak and trend of chest compression and resistance force are also close.The chest compression increased and the resistance force became smaller when the lumbar spine rubber hardness for the HA76 was assembled compared to HA80.