Based on the phenomenon that acoustic emissions (AE) generated by rock mass increase suddenly because of underground excavation, time sequence of AE rate in rock failure has been discussed by using statistical damage ...Based on the phenomenon that acoustic emissions (AE) generated by rock mass increase suddenly because of underground excavation, time sequence of AE rate in rock failure has been discussed by using statistical damage theory. It has been demonstrated that how the influence of confining pressure on the deformation behavior and AE characteristics in rocks can be inferred from a simple mechanics model. The results show that loading confining pressure sharply brings out increasing of AE. On the other hand, few AE emits when confining pressure is loaded sharply, and AE occurs again when axial pressure keeps on increasing. These results have been well simulated with computer and show close correspondence with directly measured curves in experiments.展开更多
Objective: To explore the mechanical behavior of lumbar spine loaded by stress and provide the mechanical basis for clinical analysis and judgement of lumbar spine fracture classification, mechanical distribution and...Objective: To explore the mechanical behavior of lumbar spine loaded by stress and provide the mechanical basis for clinical analysis and judgement of lumbar spine fracture classification, mechanical distribution and static stress. Methods: By means of computer simulation method, the constructed lumbar spine three-dimensional model was introduced into three-dimensional finite element analysis by software Ansys 7.0. The lumbar spine mechanical behavior in different parts of the stress loading were calculated. Impact load is 0-8000 N. The peak value was 8000 N. The loading time is 0-40 minutes. The values of the main stress, stress distribution and the lumbar spine unit displacement in the direction of main stress were analyzed. Results: The lumbar spine model was divided into a total of 121 239 nodes, 112 491 units. It could objectively reflect the true anatomy of lumbar spine and its biomechanical behavior and obtain the end-plate images under different stress. The stress distribution on the lumbar intervertebral disc (L3-L4) under the axial, lateral flexion and extension stress, and the displacement trace of the corresponding processus articularis were analyzed. Conclusion: It is helpful to analyze the stress distribution of lumbar spine and units displacement in static stress loading in the clinical research of lumbar spine injury and the distribution of internal stress.展开更多
文摘Based on the phenomenon that acoustic emissions (AE) generated by rock mass increase suddenly because of underground excavation, time sequence of AE rate in rock failure has been discussed by using statistical damage theory. It has been demonstrated that how the influence of confining pressure on the deformation behavior and AE characteristics in rocks can be inferred from a simple mechanics model. The results show that loading confining pressure sharply brings out increasing of AE. On the other hand, few AE emits when confining pressure is loaded sharply, and AE occurs again when axial pressure keeps on increasing. These results have been well simulated with computer and show close correspondence with directly measured curves in experiments.
文摘Objective: To explore the mechanical behavior of lumbar spine loaded by stress and provide the mechanical basis for clinical analysis and judgement of lumbar spine fracture classification, mechanical distribution and static stress. Methods: By means of computer simulation method, the constructed lumbar spine three-dimensional model was introduced into three-dimensional finite element analysis by software Ansys 7.0. The lumbar spine mechanical behavior in different parts of the stress loading were calculated. Impact load is 0-8000 N. The peak value was 8000 N. The loading time is 0-40 minutes. The values of the main stress, stress distribution and the lumbar spine unit displacement in the direction of main stress were analyzed. Results: The lumbar spine model was divided into a total of 121 239 nodes, 112 491 units. It could objectively reflect the true anatomy of lumbar spine and its biomechanical behavior and obtain the end-plate images under different stress. The stress distribution on the lumbar intervertebral disc (L3-L4) under the axial, lateral flexion and extension stress, and the displacement trace of the corresponding processus articularis were analyzed. Conclusion: It is helpful to analyze the stress distribution of lumbar spine and units displacement in static stress loading in the clinical research of lumbar spine injury and the distribution of internal stress.