异响性能预防设计：ANSA & META建模E-line分析

编者按：E-line方法的一个核心思维就是求解两个相邻部件之间在时域内的相对位移，并依此计算值为评估异响风险的参数，但有一个问题就是怎么来设定这个平均值（Mean value）为相对参考值？恐怕还是离不开多个参考车型数据库（Competitive
vehicle database）的积累才能给出相对合理的参数。

我们都知道异响的模型对后门结果又很大的影响，尤其是几何形状复杂的塑料件，相比通常CAE仿真所采用的Hypermesh前处理软件，ANSA在网格质量调整方面，有强大的自动调整功能，还提供了多种手动网格调整工具。 其次，ANSA具有丰富的CAD接口，能方便的和各种CAD进行数据交流。尤其是对UG,CATIA,pro-e主流CAD的接口方面。同时，ANSA提供了批处理数据传输的能力，这一点比Hyperworks要快的多。

不妨谈一谈你的想法和应用感受。

ANSA / META 工具栏中的E-lines方法

The BETA CAE Systems software suite offers a complete toolbox for setting up a ready to run model for analysis using the E-LINE method, and evaluating the results. Through it ANSA pre-processor and META post-processor, it is possible to streamline the process and achieve significant benefits in terms of process time reduction and
simulation quality.

E-Lines的创建

An E-Line in ANSA is a 3D curve that lays between the two components of interest, along which their relative displacement is evaluated under a specific load.

The ANSA pre-processor offers a functionality to select the areas of interest and build the corresponding E-Lines manually. Moreover, analysts can employ the automated
tool to identify and create automatically all possible E-Lines in a complete model.

ANSA软件中的E-Lines管理器

ANSA has implemented a special tool that offers to the analyst a compact and user friendly interface for the general handling of the E-lines. Specifically, the E-Lines Manager of ANSA, through its interface, can guide the user to not only define easily the needed settings for each E-Line but also offers the ability of a bulk production of the respective FE-Representations. These representations correspond to the available solver keywords.

所支持的求解器

The model set up through ANSA pre-processor is possible both for NASTRAN and LS-DYNA. Considering NASTRAN, RBE3-CBUSH-RBE3 are being created each one oriented by a COORD_NODES_R local coordinate system. As far as LS-DYNA is concerned, *ELEMENT_BEAM_ELFORM_6 are created each one oriented by a *DEFINE_COORDINATE_NODES_DIR_Z and all of them tied to the master and slave area by a *CONTACT_TIED_NODES_TO_SURFACE.

META中的后处理

The META post-processor offers the ability through a special tool, the Squeak and Rattle toolbar, to present, in various ways, the results of the solution. 2D plots and histograms of the relative displacement either for a specific pair of nodes or for the
whole E-LINE can be created. Moreover, contour and vector plots offer the
representation of the results on the 3D model. Finally, reports can be automatically created to inform the analyst if phenomena of Squeak and Rattle exist in the simulation model.

使用META中的异响工具条来绘制相对位移曲线

Using the META Squeak and Rattle toolbar, the analyst can plot massively for all selected E-Lines, the relative displacement between all the corresponding pairs of nodes. As a result, one can have an overview of how a specific phenomenon, either Squeak or Rattle, is developed along the gap between two components.

彩色图和相位 显示图例

Another functionality which is really important for Squeak and Rattle analysis is the interaction with the 3D model. Once the user has loaded the geometry of the simulation model in META, the Squeak and Rattle toolbar enables the analyst to select the desired E-Lines and have the geometry in contour or vector plot according to the respective results of relative displacement.

Color map图结果评价和报告生成

META Squeak and Rattle toolbar offers the ability to run on a full model analysis and produce a Contour plot having as criteria the existence or not of Squeak or Rattle and
simultaneously build automatically a report that contains in tables all the data needed.

采用BETA CAE仿真的优点

The BETA CAE Systems software suite, having incorporated dedicated tools for Squeak and Rattle analyses offers a complete toolset for facilitating and streamlining the S&R CAE processes offering benefits such as:

• Time reduction during pre-processing through the automated identification and
  creation of E-LINEs.
• The control, manipulation and bulk E-LINE realization of numerous 3D curves is
  significantly facilitated through the E-LINEs Manager further facilitating the
  process and saving additional time.
• Model set up is available for both NATRAN and LS-DYNA.
• The capabilities offered by the META post processor for automatic reports creation,
  direct demonstration of the results on the components of interest, and the instant
  general overview of the most crucial areas almost eliminates post-processing
  effort and duration.