人工边界在大型软件中的应用
发布时间：2018-07-29 09:02
【摘要】：人工边界是采用有限化的方式处理无限域时，为模拟连续介质辐射阻尼影响而人为引进的虚拟边界，是场地地震反应分析和土-结构动力相互作用分析不可回避的问题，其中，粘性边界和粘弹性边界最方便应用于大型通用有限元软件中。本文主要介绍了粘性和粘弹性边界在ANSYS和ANSYS/LS-DYNA软件中的使用方法，并对其精度进行了说明；此外还介绍了在ANSYS中实现精度更高的透射边界的方法。本文的主要内容如下： 1.详细介绍了粘性边界和粘弹性边界在ANSYS中的使用方法，通过添加弹簧单元的方式，将LS-DYNA软件中自带的粘性边界改进为粘弹性边界。 2.通过大量不同的算例，比较了粘性边界和粘弹性边界在解决不同问题中的吸能效果，结果表明：对于二维和三维波源问题，粘弹性边界优于粘性边界，特别是粘弹性边界解决飘移作用很明显。对于散射问题，，粘弹性边界的精度比粘性边界的精度有所提高。另外，需要注意的是，当直接采用LS-DYNA中粘性边界进行散射问题分析时，若采用程序默认的时间步长Δ t，结果可能会出现飘移现象，可以采用减小Δt的方法或采用增加弹簧的方法（即粘弹性边界）解决。 3.介绍了透射边界在ANSYS中的二次开发应用方法并通过波源算例、散射算例比较了几种边界的精度，结果表明：二阶透射边界精度高于粘弹性边界和粘性边界。 最后对全文工作进行了总结，并提出今后需要进一步研究的内容。
[Abstract]:Artificial boundary is the artificial boundary introduced to simulate the radiation damping effect of continuous medium when the infinite domain is dealt with in a finite way. It is an unavoidable problem in site seismic response analysis and soil-structure dynamic interaction analysis. Viscous boundary and viscoelastic boundary are most convenient to be used in large general finite element software. In this paper, the application of viscous and viscoelastic boundary in ANSYS and ANSYS/LS-DYNA software is introduced, and its precision is explained. In addition, the method of realizing the transmission boundary with higher precision in ANSYS is also introduced. The main contents of this paper are as follows: 1. The application method of viscous boundary and viscoelastic boundary in ANSYS is introduced in detail. By adding spring element, the intrinsic viscous boundary in LS-DYNA software is improved to viscoelastic boundary. 2. The energy absorption effects of viscous boundary and viscoelastic boundary in solving different problems are compared by a large number of examples. The results show that the viscoelastic boundary is superior to the viscous boundary for two-dimensional and three-dimensional wave source problems. In particular, the viscoelastic boundary solution to drift is obvious. For scattering problems, the accuracy of viscoelastic boundary is higher than that of viscous boundary. In addition, it should be noted that when the scattering problem is analyzed directly by using the viscous boundary in LS-DYNA, if the program's default time step 螖 t is used, the result may appear drift phenomenon. It can be solved by reducing 螖 t or adding spring (that is viscoelastic boundary). This paper introduces the secondary development method of transmission boundary in ANSYS and compares the accuracy of several kinds of boundary by wave source example and scattering example. The results show that the accuracy of the second order transmission boundary is higher than that of viscoelastic boundary and viscous boundary. Finally, the paper summarizes the work and puts forward the contents that need further study in the future.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU435;TP319
本文编号：2152176
[Abstract]:Artificial boundary is the artificial boundary introduced to simulate the radiation damping effect of continuous medium when the infinite domain is dealt with in a finite way. It is an unavoidable problem in site seismic response analysis and soil-structure dynamic interaction analysis. Viscous boundary and viscoelastic boundary are most convenient to be used in large general finite element software. In this paper, the application of viscous and viscoelastic boundary in ANSYS and ANSYS/LS-DYNA software is introduced, and its precision is explained. In addition, the method of realizing the transmission boundary with higher precision in ANSYS is also introduced. The main contents of this paper are as follows: 1. The application method of viscous boundary and viscoelastic boundary in ANSYS is introduced in detail. By adding spring element, the intrinsic viscous boundary in LS-DYNA software is improved to viscoelastic boundary. 2. The energy absorption effects of viscous boundary and viscoelastic boundary in solving different problems are compared by a large number of examples. The results show that the viscoelastic boundary is superior to the viscous boundary for two-dimensional and three-dimensional wave source problems. In particular, the viscoelastic boundary solution to drift is obvious. For scattering problems, the accuracy of viscoelastic boundary is higher than that of viscous boundary. In addition, it should be noted that when the scattering problem is analyzed directly by using the viscous boundary in LS-DYNA, if the program's default time step 螖 t is used, the result may appear drift phenomenon. It can be solved by reducing 螖 t or adding spring (that is viscoelastic boundary). This paper introduces the secondary development method of transmission boundary in ANSYS and compares the accuracy of several kinds of boundary by wave source example and scattering example. The results show that the accuracy of the second order transmission boundary is higher than that of viscoelastic boundary and viscous boundary. Finally, the paper summarizes the work and puts forward the contents that need further study in the future.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU435;TP319
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