Automation of Post-Processing Techniques for Iterative design Procedure Using TCL Script

Transcription

1 Automation of Post-Processing Techniques for Iterative design Procedure Using TCL Script Pravinkumar Sonavane Technical lead-cae atechnologies.com Sagar Patel CAE Engineer gies.com Pankaj Bhirud Technical Specialist-CAE ogies.com Abbreviations: TCL Tool Command Language, GUI Graphical user Interface Keywords: Post-Processing, HyperView, HyperGraph, CAE, FEA, TCL program Abstract Computer Aided Engineering (CAE) is for the use of computational methods to accurately simulate engineering problems across wide spectrum of domains. CAE has been prevalent in automobile industries for a long time. The most important task in CAE is a result interpretation, for that we need Post-Processer like HyperView. When we are analyzing multiple result files, the process of importing each result file in different window, setting appropriate result type, contour, color change of contour etc. can be automated. All these activities are automated using newly developed TCL script. This paper discusses about application of customization for post processing techniques for iterative design procedures. This script can also perform operations like plotting force displacement plot, energy plots in HyperGraph. The advantage of newly developed script is to increase efficiency and productivity. This script will be useful where iterative design procedures are used. Introduction CAE tools are widely used in automotive industry. It has allowed automakers to predict the safety, comfort and durability behavior of the vehicle using computer simulations rather than physical prototype testing each time. Post-Processing is an important part of CAE Simulation. When we are working on iterative design, we need to Post-Process the result files multiple times. This leads to more time consumption. Also when we have multiple files to Post-Process, the operation such as, file opening, setting contour & Legends and plotting graphs takes a lot of time which is a repetitive task and can be automated. Some time it may cause inaccuracies when performed manually. In order to avoid inaccuracies in the results, one needs to capture the repetitive tasks, standardize and automate them. In the current paper, the process of automating the Post-Process results using TCL script is discussed in detail. Process Methodology A TCL script is written for HyperView and HyperGraph to develop an interactive GUI that automates the Post-Processing of results file. The currently script has been developed for Ls-Dyna result files (.ptf, Binout). The analysis in which we have to check the deflection for a particular load at different positions, we generate one set of results for each position. We need to present the combine results on a complete model, so the situation comes where we need to open each set of results in HyperView and 1

2 HyperGraph. Here, the script works to automate the said process. The overall flow of the script is shown in Fig.1. The Input given to the script is a folder in which all the result folders are kept. The details of Input folder and result file are shown in Fig.2. Figure 1 Flowchart of Post-Processing Script Figure 2 Input folders and result files in each folder The name of result folder should be in sequence such as SDS1, SDS2, SDS3 and so on. Each result folder consists of.ptf files and Binout files. Once we run the script in HyperView environment. It pops up with GUI asking for folder selection. We need to provide the folder path in which results are stored and Click on GO Button. The script will start and read the result folders and generates HyperView 2

3 pages one more than number of result folder. One extra page is reserved to takeout model images. And at the same time a script creates a folder named Result in working directory which is later used to store the curves and images exported from a script. The results obtained through a script as shown in Fig.3. Figure 3 Result Windows generated through Script The detail description of results in each window is explained below. 1) First Window Firstly, script sets a Window to HyperView Environment then read a respective result file from a folder. Then, open ptf files and apply displacement magnitude contour to the complete model. And, after that the TCL Script works towards a legend edit. It then changes a legend bottom level dark blue color to gray color. This step is important to visualize the hot spots and to understand results clearly. Script also removes unnecessary entities such as Maximum value, Minimum value and part ID. 2) Second Window Script sets a Window to HyperGraph Environment then read respective result file from a folder. Then, open Binout files and plot the energy curves ID. Energy curves include Total Energy Curve, Internal Energy Curve, Kinetic Energy Curve, Sliding Interface Energy Curve and Hourglass Energy Curve. All these curves are plotted on a single graph so that we can study the behavior of a model and relation between energy curves. 3) Third Window - Script sets a Window to HyperView Environment then read a respective result file from a folder. Then, open.ptf files and apply an effective plastic strain contour to the complete model so that TCL Script works towards the legend edit. It then changes the legend bottom level dark blue color to gray color. This step is important to visualize the hot spots and to understand results clearly. The script also removes unnecessary entities such as Maximum value, Minimum value and part ID. 4) Fourth Window Script sets a Window to Hypergraph Environment then read a respective result file from a folder. Then, open Binout files and plot the resultant displacement v/s time plot and rcforce v/s time plot. It then generate cross plot to get the Force Displacement curve on a graph. It shows only Force Displacement curve on a graph and hides other two curves then export the displayed Force Displacement curve to Result folder as a csv file and rename the curve name as a position name or file name. 3

4 The last HyperView page is reserved to export the images in standard views. In this, imported model will be set to different standard views such as right, left, top, bottom, front, back and iso. Model will be set to one view and export.jpg image then set to second view and export.jpg image in result folder, it continues till all standard views complete. Fig.4. shows the model in iso standard view and Result folder with exported images and graphs from tcl script. Figure 4 Model and exported images in Standard Views Results & Discussions Auto Post-Process script based on the input result files, helps engineer to reduce repetitive task and non-value added task which leads to huge time saving. Thus, engineers get sufficient time for better engineering and analyze the results. This is more useful to design a better product. For analyzing any product we need to do some iteration. And, for the each iteration we need to post-process the results. Thus, this script is very useful to save time when designing iterative procedures. The exported results from script may be used as a input for other script such as VBA to generate the reports in presentation format. Benefits Summary The present method of Post-Processing discussed is highly accurate and speedy as compared to any other existing manual method. This script eliminates human intervention and thus increasing the accuracy of result interpretation. Based on few assumptions, one CAE engineer can save up to 360 hrs by using this script in one year. Challenges The script greatly depends upon the result folder names and sequence of result files names. Any discrepancy between the folder name and result file name might lead to error in Post Processing script. Future Plans Script can be enhanced to make a Comprehensive tool to read the results with different names. So that it can be used to post-process the result for any load case. Also, we need to visualize a particular part instead of complete model so that flexibility can be added in script for further reduction in time. 4

5 Conclusions The Post Processing with multiple files can be done with maximum accuracy in a very less time. The manual procedure would otherwise have typically taken very large time. Human interaction is very minimal; hence chances of error are very less. This has a very user friendly and interactive GUI. Time required to do the repetitive task has been reduced. A CAE engineer, who is new to Analysis and postprocess can easily follow the procedure and generate the reports ACKNOWLEDGEMENTS We are grateful to each and every individual who directly or indirectly supported us in accomplishing this paper, we are extremely thankful to all the onshore and offshore members of Cabin Trim Durability team for their constant inputs and assistance towards the completion of this paper. REFERENCES Journal Papers: 1) M. Merkel, A. Schumacher, Automated Optimization Process for a CAE Driven Product Development,Journal of Mechanical Design, 125(4), 2004, ) OkbaHamri, Jean Claude Léon, Franca Giannini, Bianca Falcidieno, Computer Aided Design and Finite Element Simulation Consistency, Journal of Mechanical Engineering, 56(11), 2010, , Chapters in Books: 1) Brent Welch, Ken Johns, Jeffery Hobbs, Practical Programming in Tcl and Tk (Upper Saddle River, NJ07458, Prentice Hall,2003) 2) Introduction to HM Customization Using Tcl to Control the HyperMesh Session (Altair Engineering, Inc 2013) Proceedings Papers: 1) Alejandro Palacio,XavierLatorre, CarlesMitjans, and Pablo Cruz, Automation of CAE Pre & Post Processing Activities Using Ansa&μeta Scripting Capabilities. International Conference, September, 2009, 9-11 Olympic Convention Centre,HalkidikiGree 5