Coulomb stress changes associated with strong earthquakes occurring since 1484 in Hebei Province,China are investigated. The North China block has had many large historical earthquakes and some damaging earthquakes in...Coulomb stress changes associated with strong earthquakes occurring since 1484 in Hebei Province,China are investigated. The North China block has had many large historical earthquakes and some damaging earthquakes in the past century,including the 1976 Tangshan earthquake (M =7.8) . The study area and the adjacent areas of the province comprise the most active seismic fault zones and suffer from both strong and frequent events. The North China Block,which includes the Ordos plateau and the North China plain,is part of the Archean Sino-Lorean craton and one of the most active seismic regions in the world. Its movement is accommodated on major strike-slip intraplate fault zones that strike in the E-W direction. The faults in the study area contribute to the complexity of the stress field. Seismic hazard assessment in this region is attempted by calculating the change of the Coulomb failure function ( ΔCFF) arising from both the coseismic slip of strong events (MS≥6.5) and the stress built up by continuous tectonic loading on major regional faults. At every step of the stress evolutionary model an examination of possible triggering of each next strong event is made and the model finally puts in evidence that the fault segments that are apt to fail in an impending strong event,thus providing future seismic hazard evaluation. In this paper,the results of ΔCFF for Zhangjiakou fault, Xiadian fault and Langfang fault have been shown as examples to express the possiblity of generating future seismic hazard.展开更多
There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement compo...There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement components. In such finite element formulation, the stress components are constant in each element and they are discontinuous in any two neighboring elements. Therefore, the bases of using the virtual work principle in such elements are unreliable. In this paper, we introduce a new method, namely, the compatible stress iterative method, to eliminate the above-said difficulty. The calculated examples show that the calculation using the new method in dynamic finite element analysis of high velocity impact is valid and stable, and the element stiffness can be somewhat reduced.展开更多
In this paper, the boundary element method is applied to investigate the internal state of stress of autofretted tube with notch and the calculated results are important in the practical design.
基金funded by the project of "Strong Motion Records in the Seismic Resistance of the Tangshan Region ( No. 11276905D) ",Department of Science and Technology of Hebei Province,China
文摘Coulomb stress changes associated with strong earthquakes occurring since 1484 in Hebei Province,China are investigated. The North China block has had many large historical earthquakes and some damaging earthquakes in the past century,including the 1976 Tangshan earthquake (M =7.8) . The study area and the adjacent areas of the province comprise the most active seismic fault zones and suffer from both strong and frequent events. The North China Block,which includes the Ordos plateau and the North China plain,is part of the Archean Sino-Lorean craton and one of the most active seismic regions in the world. Its movement is accommodated on major strike-slip intraplate fault zones that strike in the E-W direction. The faults in the study area contribute to the complexity of the stress field. Seismic hazard assessment in this region is attempted by calculating the change of the Coulomb failure function ( ΔCFF) arising from both the coseismic slip of strong events (MS≥6.5) and the stress built up by continuous tectonic loading on major regional faults. At every step of the stress evolutionary model an examination of possible triggering of each next strong event is made and the model finally puts in evidence that the fault segments that are apt to fail in an impending strong event,thus providing future seismic hazard evaluation. In this paper,the results of ΔCFF for Zhangjiakou fault, Xiadian fault and Langfang fault have been shown as examples to express the possiblity of generating future seismic hazard.
文摘There is a common difficulty in elastic-plastic impact codes such as EPIC[2,3] NONSAP[4], etc.. Most of these codes use the simple linear functions usually taken from static problem to represent the displacement components. In such finite element formulation, the stress components are constant in each element and they are discontinuous in any two neighboring elements. Therefore, the bases of using the virtual work principle in such elements are unreliable. In this paper, we introduce a new method, namely, the compatible stress iterative method, to eliminate the above-said difficulty. The calculated examples show that the calculation using the new method in dynamic finite element analysis of high velocity impact is valid and stable, and the element stiffness can be somewhat reduced.
文摘In this paper, the boundary element method is applied to investigate the internal state of stress of autofretted tube with notch and the calculated results are important in the practical design.
