外文翻譯---對(duì)由ansys開發(fā)的大型工程模型的降階 英文

1、Model Order Reduction for Large Scale Engineering Models Developed in ANSYSEvgenii B. Rudnyi and Jan G. KorvinkIMTEK, Institute of Microsystem Technology Freiburg University Georges-K¨ ohler-Allee, 103 D-79110, Frei

2、burg, Germany {rudnyi,korvink}@imtek.de http://www.imtek.uni-freiburg.de/simulation/Abstract. We present the software mor4ansys that allows engineers to employ modern model reduction techniques to finite element models d

3、eveloped in AN- SYS. We focus on how one extracts the required information from ANSYS and performs model reduction in a C++ implementation that is not dependent on a particular sparse solver. We discuss the computational

4、 cost with examples related to structural mechanics and thermal finite element models.1 IntroductionThe model order reduction of linear large-scale dynamic systems is already quite an established area [1]. In many papers

5、 (see references in [2]), advantages of model reduc- tion have been demonstrated for a variety of scientific and engineering applications. In the present work, we focus on how engineers can combine this technique with ex

6、isting commercial finite element software in order to– Speed up a transient or harmonic analysis, – Generate automatically compact models for system-level simulation, – Incorporate finite element packages during the desi

7、gn phase.Model reduction is conventionally applied to a large-scale dynamic system of the first order as follows E ˙ x = Ax + Buy = Cx (1.1)where A and E are system matrices, B is the input matrix, C is the output matrix

8、. The aim of model reduction is to generate a low-dimensional approximation to (1.1) in a similar form Er ˙ z = Arz + Bruy = Crz (1.2)that describes well the dependence of the output vector y on the input vector u and so

9、 that, at the same time, the dimension of the reduced state vector z is much less than the dimension of the original state vector x.J. Dongarra, K. Madsen, and J. Wa´ sniewski (Eds.): PARA 2004, LNCS 3732, pp. 349–3

10、56, 2006. c ? Springer-Verlag Berlin Heidelberg 2006Model Order Reduction for Large Scale Engineering Models Developed in ANSYS 351Fig. 1. mor4ansys block-scheme2.1 Interfacing with ANSYSThe development of the first modu

11、le happen to be rather difficult because most users of a commercial finite element package do not need the capability to extract the dynamics system in the form of Eq (1.1) or (2.3) and, as a result, this is not a trivia

12、l operation.ANSYS is a huge package and its behavior is not completely consistent. For exam-ple, the information described below is not applicable for the fluid dynamics module FLOTRAN.Our software reads the binary EMAT

13、file with element matrices in order to assembleglobal system matrices. The file format is documented and ANSYS supplies a library of Fortran subroutines to work with it [10]. An example of how one can use them can be fou

14、nd in the mor4ansys code [6]. ANSYS has a special command, called a partial solve PSOLVE, with which one can evaluate element matrices for a given state vector without going through the real solution stage. This allows u

15、s to generate an EMAT file efficiently for a given model. However, it was necessary to overcome the following problems:– The EMAT file does not contain the information about either Dirichlet boundaryconditions or equatio

16、n constraints. They should be extracted separately.– The EMAT file has a contribution to the load vector from element matrices only. Ifnodal forces or accelerations are used to apply the load, this information should als

17、o be extracted individually.– It is necessary to assemble the global matrices from the element matrices.During the solution phase, ANSYS can write a binary FULL file with the assembledsystem matrices. When we started the