【作者】 张延；

【导师】 赵成刚；

【作者基本信息】 北京交通大学 ， 岩土工程， 2008， 硕士

【摘要】 近些年粘弹性人工边界被提出,利用有限元通用软件ANSYS中提供的弹簧-阻尼单元(Spring-damper),可以较容易的模拟粘弹性人工边界条件。由于该方法简单,又具有较好的精度;更重要的是它可以方便地在通用的商业软件中实现,近些年它在结构-地基动力相互作用分析问题中得到了有效的应用。通常这些应用是针对一个结构物的情况,即所谓单源散射。但有些情况下,例如在多跨桥梁、铁路路基等延伸较长的结构中,桥梁基础或轨枕有多个并且相距可能很远;这种情况是多源散射问题。如果在这种情况下仍然采用单源散射问题的粘弹性人工边界,会产生误差。而粘弹性人工边界的精度是评价其工程应用价值的一个重要指标。针对这种情况,本文在原有粘弹性人工边界的基础上,提出了多源散射粘弹性人工边界,该方法适用于具有多点内源输入荷载和多点地震动输入的情况。本文用有限元软件ANSYS中提供的弹簧-阻尼单元(Spring-damper)模拟粘弹性人工边界条件,并进行了数值计算。算例表明,与单源散射粘弹性人工边界相比本文方法能够有效地提高粘弹性人工边界的计算精度。更多还原

【Abstract】 The viscous-spring artificial boundary is proposed in recent years, which is realized easily by utilizing the Spring-damper cell in finite element software of ANSYS. The combination method of the finite element method and the viscous-spring boundary is used effectively in dynamic soil-structure interaction because it’s simply ,high accuracy and convenient actualization in current commercial software in recent years. The method is applied in the situation of single scattering source.But in the long-outspread structure of multiple-span bridge and railway roadbed, the distance between of bridge foundations and sleepers may be far ,which are called multi-points scattering problem. The error would be caused if the viscous-spring artificial boundary of single scattering source is used in above situations. Meanwhile, the artificial accuracy is an important criterion which evaluate its application in engineering.On the basis of prevenient viscous-spring artificial boundary, the viscous-spring artificial boundary of multi-points scattering source is proposed, which is suitable for the input of multi-points scattering and seismic wave. The numerical calculate is carried by simulating the viscous-spring artificial boundary with the Spring-damper cell in ANSYS. The results indicate the proposed method in the paper can improve the accuracy of viscous-spring artificial boundary compared with the situation of single scattering source.更多还原