Based on the statics theory, a novel and feasible twice-suspended-mass method(TSMM) was proposed to deal with the seldom-studied issue of fault diagnosis for damping springs of large vibrating screen(LVS). With the st...Based on the statics theory, a novel and feasible twice-suspended-mass method(TSMM) was proposed to deal with the seldom-studied issue of fault diagnosis for damping springs of large vibrating screen(LVS). With the static balance characteristic of the screen body/surface as well as the deformation compatibility relation of springs considered, static model of the screen surface under a certain load was established to calculate compression deformation of each spring. Accuracy of the model was validated by both an experiment based on the suspended mass method and the properties of the 3D deformation space in a numerical simulation. Furthermore, by adopting the Taylor formula and the control variate method, quantitative relationship between the change of damping spring deformation and the change of spring stiffness, defined as the deformation sensitive coefficient(DSC), was derived mathematically, from which principle of the TSMM for spring fault diagnosis is clarified. In the end, an experiment was carried out and results show that the TSMM is applicable for diagnosing the fault of single spring in a LVS.展开更多
In order to study the mechanism of seismic isolation、seismic absorption and the limiting strength of Dougong under the seismic vertical action in Chinese timber structure, by following the building regulation of Ying...In order to study the mechanism of seismic isolation、seismic absorption and the limiting strength of Dougong under the seismic vertical action in Chinese timber structure, by following the building regulation of Ying Zao Fa Shi published in Song Dynasty (960A.D. —1279 A.D.) in China history, the three Dougong models with the scale of 1/3.52 of the prototype structure are made, and on which the limiting strength experiments are carried out. The experimental phenomenon is observed, and the relevant P-△ curves are drawn simultaneously. The tested results show that :under the vertical load,(1) the mechanical behaviors of Dougong can be regarded as linear-elastic mechanic model with varied modulus of elasticity, and expressed with SDOF system; (2) the first cause of the destruction of Dougong is the break of the midmost of Huagong;(3) Dougong plays a very important role in reducing obviously seismic responses of the Chinese timber structure due to the sdismic vertical transmissibility is approximate to 0.019;and ⑷ under the normal condition, the material strain and stress of Dougong are very small, and no more than 1/7 of the limiting, so the abundance of the material strength is quite large. This ensures that many Chinese ancient wooden structures have survived many violent earthquakes and stood over one thousand years.展开更多
基金Project(20120095110001)supported by the PhD Programs Foundation of Ministry of Education of ChinaProject(51134022,51221462)supported by the National Natural Science Foundation of China+1 种基金Project(CXZZ13_0927)supported by Research and Innovation Program for College Graduates of Jiangsu Province,ChinaProject(2013DXS03)supported by the Fundamental Research Funds for Central Universities of China
文摘Based on the statics theory, a novel and feasible twice-suspended-mass method(TSMM) was proposed to deal with the seldom-studied issue of fault diagnosis for damping springs of large vibrating screen(LVS). With the static balance characteristic of the screen body/surface as well as the deformation compatibility relation of springs considered, static model of the screen surface under a certain load was established to calculate compression deformation of each spring. Accuracy of the model was validated by both an experiment based on the suspended mass method and the properties of the 3D deformation space in a numerical simulation. Furthermore, by adopting the Taylor formula and the control variate method, quantitative relationship between the change of damping spring deformation and the change of spring stiffness, defined as the deformation sensitive coefficient(DSC), was derived mathematically, from which principle of the TSMM for spring fault diagnosis is clarified. In the end, an experiment was carried out and results show that the TSMM is applicable for diagnosing the fault of single spring in a LVS.
文摘In order to study the mechanism of seismic isolation、seismic absorption and the limiting strength of Dougong under the seismic vertical action in Chinese timber structure, by following the building regulation of Ying Zao Fa Shi published in Song Dynasty (960A.D. —1279 A.D.) in China history, the three Dougong models with the scale of 1/3.52 of the prototype structure are made, and on which the limiting strength experiments are carried out. The experimental phenomenon is observed, and the relevant P-△ curves are drawn simultaneously. The tested results show that :under the vertical load,(1) the mechanical behaviors of Dougong can be regarded as linear-elastic mechanic model with varied modulus of elasticity, and expressed with SDOF system; (2) the first cause of the destruction of Dougong is the break of the midmost of Huagong;(3) Dougong plays a very important role in reducing obviously seismic responses of the Chinese timber structure due to the sdismic vertical transmissibility is approximate to 0.019;and ⑷ under the normal condition, the material strain and stress of Dougong are very small, and no more than 1/7 of the limiting, so the abundance of the material strength is quite large. This ensures that many Chinese ancient wooden structures have survived many violent earthquakes and stood over one thousand years.
