as a PDF
Contents
1. 5 Interfaces between Design 6 Interface between Thermal and Structural 6 Exporting Structural Results to Optical 7 8 4 0 Running PATCOD 2 0 10 10 10 OUD PU 11 SO SUMIMALY 2056s cesocscesuvecsissucassesseessdsossssdssseasessusessssssenseeSsobabesSusdessssobaeboodeabenseoasedssveadeseabecdesestapassostacdesessoosesy Appendix A PATCOD User s Guide 13 EC EEC ECE CELE Eee eee CECE Input Requirements Output Requirements Sample Execution mianya Figures Figure 1 Overall integrated analysis 2 Figure 2 Macro for translation from relative to global coordinates 4 Figure 3 Process flow for integrated design analysis at LaRC Figure 4 Thermal gradients on o2. Includes translation of both decenters and tilts ENTER PATH NUMBER ON FILE ANALYZE gt 3 ENTER FILENAME FOR TRANSLATIONAL DECENTER DATA gt tran prt ENTER THE UNITS OF THE NASTRAN PATRAN DECENTER DATA ENTER 1 METERS CR DEFAULT 2 3 INCHES 4 FEET ENTER 1 2 3 4 OR CR gt 1 ENTER FILENAME FOR ROTATIONAL DECENTER DATA gt rot prt ENTER Code FILENAME INCL EXTENSION ie SEQ gt samplerun seq ENTER THE UNITS OF THE Code V DATA ENTER 1 MM CR DEFAULT 2 METERS ENTER gt 1 CONVERSION FACTOR FROM NASTRAN TO Code V FROM METERS 1000 000 TITLE OF RUN TITLE 41156 ENTER FOR A NEW TITLE MAX 71 CHARS A TO APPEND TO CURRENT TITLE O or cr FOR OK IGNORE ENTER A 0 CR gt a OF CHARS ALLOWED TO APPEND TO TITLE 65 ENTER APPENDAGE gt for sample run TITLE 41158 for sample run END OF SUCCESSFUL EXECUTION OUTPUT FILENAME samplerunDEF1 SEQ ENTER to stop TO EXECUTE AGAIN gt Figure 12 Sample Execution Run of PATCOD 90
3. EPD 0 22 DIM M WL 1064 0 REF 1 WTW 1 INI XAN 0 0 YAN 0 0 VUX 0 0 VLX 0 0 VUY 0 0 VLY 0 0 PRV PWL 1064 0 crystal 1 5369552 liniobat 2 232 PWL 1064 0 lithium 2 232 calcite 1 587941299 PWL 1064 0 polarcor 1 512 PWL 1064 0 isofilm 2 31 PWL 1064 0 PWL 1064 0 TR 85 1 5606 PWL 1064 0 4185 1 5606 END SO 0 0 10 973 S 0 00 0 S 0 0 6 261 ir85 GLB G1 CIR EDG 4 36 S 0 00 39 crystal STO GLB G1 XDE 0 013248884 YDE 0 000051111 ZDE 6 263700377 CIR 7 5 S 0 00 42 crystal GLB G1 XDE 0 013234866 YDE 0 000051382 ZDE 6 653700377 CIR 7 5 S 0 0 23 515 GLB G1 XDE 0 013219768 YDE 0 000051674 ZDE 7 073700377 CIR 7 5 S 101 11 2 1 SF8_SCHOTT GLB G1 XDE 0 012380112 YDE 0 000072640 ZDE 30 588656305 CIR 9 0 S 17 36 5 94 55 4 SCHOTT GLB G1 XDE 0 012305011 0 000073634 ZDE 32 688656305 CIR 9 0 Figure 11 Partial output of sample run file opticalrunDEF1 SEQ 19 kK kkk k k PATCOD TRANSLATOR VER 1 0 STRUCTURAL THERMAL INTERFACE TO OPTICAL ANALYSIS PATRAN gt Code V Developed by Maria Vallas Mitchum Aerospace Mechanical Systems Division NASA Langley Research Center October 1994 I SER A CK I CS A SC BEGIN EXECUTION sok LISTED BELOW ARE THE OPTICAL PATHS IN PATHS DAT FILE PATH ID 3 LINSS
4. and mesh to create FEM Thermal analysis P Thermal SINDA 85 Import temperatures to PATRAN and convert to thermal loads Structural analysis in NASTRAN Import deflection Develop CODE V results to PATRAN model Write out results files Develop relational file between from PATRAN CODE V surfaces and PATRAN nodes Run PATCOD Run CODE V on new model file Figure 3 Process flow for integrated design analysis at LaRC manually update part model or thermal conditions Axes and nodal based on optical performance location information should be coordinated 252 Interfaces between Design Analysis The design software most often used in this process at LaRC is Pro Engineer A part is com pletely designed in Pro Engineer which produces a three dimensional model of the part as well as all the fabrication drawings There are three basic methods available to translate from Pro Engineer CAD software to the PATRAN modeling software All of these methods have been used to produce viable models One is to mesh the solid geometry of the part in Pro Engineer and translate that mesh to PATRAN The disadvantages to this method are only the mesh is trans ferred not the underlying solid geometry so the geometry and mesh cannot be changed in PATRAN and the mesh is limited to tetrahedral or triangular elements The second method is to transfer the part from Pro Engineer to an Initial Graphics Exchange Specification IGES fil
5. for the optical elements based on summing the predicted deflections and the original positions of the elements Code V is run on the new model file and optical performance based on the dis torted system is predicted For any optical system there is usually only one PATRAN model but there can be a separate Code V model for each optical path The translation must be run for each optical path for which a deflection analysis is desired The translation can be run for a series of time steps using deflection results files for each time step to predict the performance of the sys tem as a function of time The current translator assumes the following relationship between the axes of the global Code V model and the axes of the PATRAN model As mentioned earlier the analysts should confer before model development to determine the coordinate definitions X of Code V X of PATRAN Y of Code V Y of PATRAN Z of Code V Z of PATRAN The current definition of CODE V optical code global coordinate rotations is as follows Rotation around X 0 positive for Z gt Y Rotation around Y positive for X gt Z Rotation around Z y positive for X gt Y Thus rotations translate exactly PATRAN X rotation CODE V X rotation PATRAN Y rotation CODE V Y rotation PATRAN Z rotation CODE V Z rotation If the axes of the model to be translated do not correspond to these the source code of the PATCOD translator must be adjusted accordingly and recompile
6. seq The fourth input file to PATCOD is the Code V input runstream that is to be modified File setup instructions can be found in the Code V Reference Manual The user will be asked for the length units of the optical displacements meters or mm The correction deflections from NASTRAN will be converted into the units of the Code V data Figure 10 shows a listing of the optical model file used in the sample case Output Requirements The output file generated by PATCOD will be a file identical in format to the Code V input file with the tilt and decenter values corrected This file can be read directly into the Code V analysis program During execution of PATCOD the user will be given the option of changing appending to or not changing the title of the input Code V runstream for the output product To create the output filename program PATCOD will delete seq from the Code input runstream name and append DEF SEQ to the filename The denotes a number from 1 to 9 thus allowing 9 executions of the same input Code V file For example for the Code V input filename opticalrun seq the PATCOD output filename will be opticalrunDEF1 SEQ exam ple output file is shown in Figure 11 Sample Execution A sample execution of the program is shown in Figure 12 This was run on an SGI worksta tion Bold denotes user responses 152 PATH ID 3 LINSS PATH 3 1 1827 2 1827 3 1828 4 1829 5 1830 10 1839 11 18
7. 0773469e 05 3 6529873 05 3 6529873 05 3 6529873 05 3 5177865 05 3 5454021 05 Z COMP 3 8477283 06 1 5552704 06 1 5552704 06 1 5552704 06 3 9628558 05 3 9628558 05 3 9628558 05 3 9628558 05 3 0680101e 07 2 9889063 07 2 9889063 07 2 9889063 07 7 5760530 05 4 3345481 05 1 4715331 05 1 4715331 05 1 6609254 06 1 6609254 06 1 6609254 06 5 5126438 06 7 6848610 06 Figure 9 Partial listing of sample run input file rot prt 2 7 2 RDM LEN TITLE 41055 EPD 0 22 DIM M WL 1064 0 REF 1 WTW 1 INI ADL XAN 0 0 YAN 0 0 VUX 0 0 VLX 0 0 VUY 0 0 VLY 0 0 PRV PWL 1064 0 crystal 1 5369552 liniobat 2 232 PWL 1064 0 lithium 2 232 calcite 1 587941299 PWL 1064 0 polarcor 1 512 PWL 1064 0 isofilm 2 31 PWL 1064 0 PWL 1064 0 IR 85 1 5606 PWL 1064 0 4185 1 5606 END SO 0 0 10 973 S 0 00 0 S 0 06 261 ir85 GLB G1 CIR EDG 4 36 S 0 0 0 39 crystal STO GLB G1 XDE 0 0 YDE 0 0 ZDE 6 261 CIR 7 5 5 0 00 42 crystal GLB G1 XDE 0 0 0 0 ZDE 6 651 5 0 023 515 GLB XDE 0 0 0 0 ZDE 7 071 7 5 S 101 11 2 1 SF8_SCHOTT GLB G1 XDE 0 0 YDE 0 0 ZDE 30 586 CIR 9 0 5 17 36 5 94 SSK4_SCHOTT GLB G1 XDE 0 0 YDE 0 0 ZDE 32 686 CIR 9 0 Figure 10 Partial listing of Code V runstream file samplerun seq 18 RDM LEN TITLE 411155 for sample run
8. sequence file is in the format required by the translator program PATCOD 3 0 Operation Outline The software translators responsible for accomplishing translations among design and struc tural thermal analytical models are in place and operational on SGI workstations at LaRC The model can be built in PATRAN by either analyst then translated to SINDA 85 for thermal analy sis and NASTRAN for structural analysis The geometry can be brought in from the design soft ware to create the model initially There must be communication between the analysts before the original model is built so that the final model will have levels of detail appropriate for both If the analysts desire different levels of detail thermal analysis commonly using a lower level of detail than structural analysis an identical base geometry can still be used and each analyst can create their own mesh The results from the thermal model are then interpolated to map temperatures onto the structural model The structural results are imposed on the Code V optical analysis model by building a deflected Code V model from an original undeflected model The relation ship between the structural and optical surfaces must be created as a separate file the translator does not have the capability at this time to build up the original Code V model from the PATRAN model The steps of this process are shown in Figure 3 Design part in Pro Engineer Import model to PATRAN
9. the model Geometries that are difficult to model and would perhaps be approximated are automatically translated exactly If necessary complex geometries that are not needed by the analyst can be simplified before the model is meshed for analysis Interface between Thermal and Structural Analysis The translators between structural and thermal analytical models are already built into the PATRAN system The analysts can easily use the same geometric model perform analyses through their separate software packages and share the results electronically The model building techniques to make this type of translation easier and more effective are discussed in section 2 0 To perform the thermal analysis the PATRAN model be translated to SINDA 85 a finite difference thermal analyzer For PATRAN 2 5 the PATSIN translator is used For PATRAN 3 the SINDA translator is built into PATRAN as part of the internal solver P3 Thermal The SINDA 85 model can be used to perform the thermal analysis with some modifications such as adding power sources The thermal analysis can also be performed using P3 Thermal The ana lysts often desire different levels of detail thermal analysis commonly uses a lower level of detail than structural analysis The calculated temperatures can be used to impose accurate thermal loads on the structural model regardless of whether the meshing is the same This has been veri fied using two different meshings and element
10. 2 07 1 9856306e 07 1 980587 1e 07 3 0195838 07 4 2073893 07 NON LAYERED Z COMP 2 5659674e 06 2 7003773e 06 2 7003773e 06 2 7003773e 06 4 2270349e 06 4 2270349e 06 4 2270349e 06 4 2270349e 06 2 86288 17e 06 2 7462293e 06 2 7462293e 06 2 7462293e 06 4 553281 1e 06 5 048 1267e 06 3 4143327e 06 3 4128493 06 2 9848650 06 2 9839066 06 2 9839071 06 2 6508633e 06 2 6902899e 06 Figure 8 Partial listing of sample run input file tran prt NODE 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 5 5 NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL 2 2 Displacements Rotational Load case 2 DEFAULT Static Subcase Lid 1 NON LAYERED X COMP 1 0260574e 06 6 9417621 07 6 9417621 07 6 9417621 07 5 1165048 06 5 1165048 06 5 1165048 06 5 1165048 06 7 6110814 07 6 5462359 07 6 5462359 07 6 5462359 07 1 3660440 06 5 3460775 07 6 0934498 07 6 0934498 07 4 5192374 07 4 5192374 07 4 5192374 07 7 7925378 08 9 0350142 08 3 3172248 05 3 5945090 05 3 5945090 05 3 5945090 05 8 5921063 05 8 5921063 05 8 5921063 05 8 5921063 05 3 8087783 05 3 6725578 05 3 6725578 05 3 6725578 05 7 0473361 05 8 0693906e 05 8 0773469e 05 8
11. 40 12 1840 13 1841 14 1842 15 1842 18 1843 19 1844 20 1844 16 1859 17 1860 56 1873 57 1874 58 1875 59 1875 21 1882 22 1883 23 1884 24 1884 25 1885 26 1886 27 1887 28 1888 29 1888 30 1889 31 1890 34 1891 52 1891 32 1892 33 1892 53 1892 54 1892 55 1893 35 10918 51 10918 36 1919 50 10919 37 1923 49 1923 38 1921 48 1921 39 1922 47 1922 40 1936 41 1936 46 1936 42 1937 45 1937 43 1938 44 1939 Figure 7 Sample relational file PATHS DAT 16 NODE 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 5 5 NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL NODL 2 1 Displacements Translational Load case 2 DEFAULT Static Subcase Lid 1 X COMP 1 3462827 05 1 3248884 05 1 3234866 05 1 3219768 05 1 0411768 05 1 0949720 05 1 0983229 05 1 1019316 05 1 3386085 05 1 3139176 05 1 3124853 05 1 3109428 05 4 5292277 06 3 4253403 06 5 5643013 06 5 7669140 06 3 1207521 06 3 0397493 06 3 0805 174 06 1 0231404 05 1 0150125 05 1 7324382 07 5 1111229e 08 5 1381956 08 5 1673510 08 2 0952441 06 2 1272785 06 2 1292740 06 2 1314229 06 5 5951812 08 3 6543117 08 3 6287815 08 3 6012874 08 4 1454277e 06 2 2054373e 06 8 6616740e 07 8 6765141 07 1 976045
12. 900 continue for all surfaces in path 7 maximum 200 If there is more than one path repeat data set 1 and 2 for each path PATHS DAT has been designed to house all paths in the Code V problem environment whether or not all paths are referenced during a single execution The entire PATHS DAT file should have a format similar to the following PATH ID 3 11385 7 L3NSS PATH 3 1 1850 3 1847 2 1900 4 1952 continue for all surfaces in path 3 PATH 7 2 1952 3 1850 1 1847 5 1900 continue for all surfaces in path 7 All surfaces in the Code V input runstream must be referenced they may appear in any order The key ingredient of this input file is the word PATH If this word has been omitted or mis spelled execution will terminate Execution will also terminate if a surface number has been omitted or if a structural node number is not reflected in the structural input data sets the files in the following section See Figure 7 for a listing of the PATHS DAT file used in the sample case 14 2 Files 2 3 Decenter Input Files translation data prt rotation data prt prt files are text report files generated by P3 The structural analysis program NASTRAN is executed and the output2 results file is read into P3 Nodes corresponding to the optical nodes are selected and under the results menu the user chooses the desired static subcase The user then chooses the text report option in order to genera
13. NASA Technical Memorandum 110153 Integration of Design Structural Thermal and Optical Analysis and User s Guide for Structural to Optical Translator PATCOD R M Amundsen W S Feldhaus A D Little and M V Mitchum Langley Research Center Hampton Virginia March 1995 National Aeronautics and Space Administration Langley Research Center Hampton Virginia 23681 0001 Integration of Design Structural Thermal and Optical Analysis and User s Guide for Structural to Optical Translator PATCOD Table of Contents 55 554 5552555 2 6 4 6 6 4 6 6 6 6 661066606066 6 661066666066 666 066 1 0 Background eose oossoo soosis issos riseire L 2 0 Model Development iscciescssscsoassceccessscossassicessaocscassncssonsdeossadecossdansscacsuasscsstoassescteassesevoassoocdanssoescansdoonsadesoon 2 cea 2 3 4 3 0 2
14. PATRAN documentation should be consulted for the most up to date method available The thermal results imported into the PATRAN model can be used in the structural analysis software to calculate thermally driven stresses and deflections based on the predicted temperature distribution In this particular case the structural analysis was performed in NASTRAN but any structural analysis software with an interface to PATRAN can be used These thermal stresses can be summed with any load driven stresses to produce a total reaction of the system to the environmental constraints One advantage to the integrated method is the capability for viewing temperatures that are mapped back onto the geometry of the part This provides a concrete display that can be used for demonstration of effects or for de bugging the model An example is shown in the grey scale plot of Figure 4 The color temperature map can be animated to follow a time sequence of ther mal events on a Exporting Structural Results to Optical Analysis Most optical models start with the assumption that the system is aligned and at rest The op tical analyst inputs surfaces sources and objects at their designed location and determines the performance of the system The optical analysis code currently used by many analysts at LaRC is Code V During actual operation of the optical system there will often be factors that cause distortions to the aligned system In the case of an opti
15. RAN and output the model in the Code V format The assumed user is an optical analyst who requires true optical performance predictions of an optical system based on thermal gradients and stresses across the system Before PATCOD is executed the user must have successfully executed the NASTRAN and or PATRAN programs and set up a typical Code V input runstream It is assumed that the modeling details for both analyses described in the body of this paper have been followed De tails of all input data sets are described in the following section Input Requirements PATCOD has been compiled and executed on several computer systems SGI workstation UNIX 77 compiler and VAX VMS minicomputer FOR compiler A version for PC DOS F77L com piler is available upon request The program executes in seconds in an interactive environment Input Requirements Four external input data files must exist in the user s local directory at time of execution Two of the input files are user generated and two are output products of PATRAN 3 P3 All records of all input files are read using the free field format structure 1 File PATHS DAT or paths dat PATHS DAT is the relational file that relates the optical surfaces in the Code V model to the structural nodes in the PATRAN model This file is user generated requiring the knowledge of the surface locations in the Code V runstream model and the associated PATRAN structural nodes loc
16. alyses based on the predicted deflections due to temperature and load distributions Most of these inte sis gration and interface steps also possible with other packages although some of the translators were developed or modified for use with these specific software packages The overall method used at LaRC is depicted in Figure 1 Pro Engineer design PATRAN modeling and results visualization NASTRAN structural analysis CODE V optical analysis SINDA 85 thermal analysis Figure 1 Overall integrated analysis process 2 0 Model Development Thermal There are several rules that must be followed in building a PATRAN model that can be used for both thermal and structural analyses The most important is that the analysts communicate before the model is built to ensure that all requirements on the model are considered The rules listed below may change as the PATRAN software changes but are always good things to con sider If not noted otherwise these apply to both PATRAN 2 5 and PATRAN 3 P3 The methods have some differences since PATRAN 2 5 uses the elements of the model as thermal nodes and thus the temperatures must be extrapolated to the structural nodes PATRAN 3 uses the finite element nodes as the nodes of the thermal model The following are key items for cor rect operation of the thermal translator e Solid elements that are to connect must have four identical corner nodes on the face they sha
17. alysis menu The user must specify in P3 that nodal rotations are required This is accomplished by checking the nodal rotation option under the results filtering menu of translation parameters The default for P3 is to read only nodal translations from the NASTRAN output2 file The optical nodes are selected in P3 by the user and placed in a nodal filter The post processing is then performed only on this filtered group of optical component nodes in order to generate two text report files with a prt extension for example tran prt and rot prt The text report post processing option must be chosen twice once for translational displacements and once for rota tional displacements If a program other than P3 is used subroutine READDEC must be changed or the deflection results should be placed in the same format as the result files generated by P3 There is a limitation of 2000 structural nodes that may be referenced The user will be asked during execution for the units of length used in the structural analysis meters mm inches or feet The fourth file is the Code V input runstream that is to be modified The Code V Reference Manual gives file setup instructions The user will be asked during execution for the units of length of the optical displacements meters or mm The correction deflections from NASTRAN will be converted into the units of the Code V data See section 3 0 Exporting Structural Re sults to Opt
18. am developed at LaRC Its func tion is to read a typical Code V program optical model input runstream update the decenter and tilt values with the correction values generated by a structural analysis program such as NASTRAN and output the model in the Code V format The program currently uses the struc tural analysis results in the format output by PATRAN PATCOD has been compiled and exe cuted on several computer systems PC DOS using F77L compiler SGI workstation UNIX 77 compiler VAX VMS minicomputer FOR compiler The program executes in seconds in an interactive environment Input Four external data files details described in Appendix A PATCOD User s Guide must exist in the user s local directory for execution to take place One file paths dat must be written by the user in a specific format to describe the relationship of the path of optical surfaces to the element node numbers in the structural analysis There is no restriction on the number of paths that may exist but a maximum of 200 surfaces is imposed on each path or the program must be modified The path chosen from the paths dat file must be the same as the Code V path being analyzed Two files are required to describe the translation and rotation decenter correction values These can be generated by any structural analysis program and are output by PATRAN 3 For 10 NASTRAN results are translated from a NASTRAN output2 into P3 under the an
19. ations The term path is used in Code V to describe the sequence of locations or surfaces that a beam of light will travel Each Code V input runstream defines a unique path All path descriptions must reside on the PATHS DAT file There are no limits on the number of paths but a limit of 200 surfaces for each path definition is imposed The records in the PATHS DAT file for N paths are as follows bold denotes a line in the file Record 1 required header record fixed alphanumeric field for identification Example PATH ID Records 2 N 1 describe the N paths in the file using two words per record where word_1 path number integer word_2 name describing the path alphanumeric Example 3 LINSS 7 L3NSS During execution the user is asked which path he wishes to analyze The path chosen must be the same path as the Code V input runstream to be analyzed Records N 2 M two data sets for each path where Data set 1 header record for each path description set with two words where word_1 fixed alphanumeric word PATH word_2 path number integer Data set 2 a set of records relating each optical surface to the corresponding structural node Each record contains two words where _1 Code V surface number integer word_2 structural node number integer Example PATH 3 1 1850 3 1847 2 1900 4 1952 continue for all surfaces in path 3 maximum 200 PATH7 2 1952 3 1850 1 1847 5 1
20. cal bench with powered optical compo nents mounted on it there can be thermal gradients across the bench These will cause minute warping of the bench and result in significant distortion of the optical system from its baseline aligned performance There can also be structural loads imposed which cause deflections and both the thermal and mechanical loading environments can be changing with time There is an existing translator that will take the deformation of a single optical element such as a lens in NASTRAN and translate the appropriate information to Code V to determine the distorted lens performance However for the optical bench structure a method was needed to look at changes in the overall performance based on distortions of the entire bench not only a single element To accomplish this an output file of nodal deflections is generated by the structural analysis software with six values for each optical surface rotations and translations in each of three axes The deflections can be due to thermal structural or any combination of loading conditions A relational file is developed for that model that relates the nodes in the PATRAN model to the optical surfaces in the Code V model Translation software PATCOD was developed at LaRC which first reads the structural analysis deflection file the relational file and copy of the unde flected Code V model It then produces a new Code V model that has revised decenters and tilts
21. d Pictorial Example The following figures show the process pictorially for an example optical bench All figures are grey scale versions of color mappings and thus do not lend themselves to interpretation of the exact numerical results The figures are intended only to present a physical idea of the process Figure 4 shows the thermal results for a given set of conditions including power to some optical components Only the optical bench itself is shown Figure 5 shows the structural deflection in reaction to those thermal loads in the x direction only The irregular spots of reduced motion are due to the presence of stiffening shear blocks within the optical bench Figure 6 shows a single optical path from the Code V model with the optical components and optical beam The deflec tion of the beam is represented by the different shades of grey The Code V model was imported into P3 in order to view the deflection graphically Figure 4 Thermal gradients on optical bench C Figure 5 Structural x deflections due to thermal load in meters 25 83 25 20 25 58 25 45 25 32 25 19 10 5 8144 09 4139 247 e j 2 fei Lt 3 519 00 3 182 I 1 275 00 amp Figure 6 Translation to optical code single optical beam path with deflection in 4 0 Running the PATCOD Translator Purpose The translator PATCOD is a FORTRAN 77 computer progr
22. demanded of any analysis process is to do it faster and better create a more stream lined process and include all known variables to produce the best possible predictions These goals can be accomplished by using an integrated process to accomplish design and all analyses The heart of the concurrent engineering process described here is the use of a single integrated model for thermal and structural analysis of a system This allows a saving of time in the thermal and structural analysis work since only one geometric model must be developed It facilitates electronic transfer of data between all types of analysis such as transfer of exact thermal gradients to be used in structural analysis Finally it produces greater model accuracy since the model can be directly imported from the design software package This integrated analysis process has been built around software that was already in use by de signers and analysts at LaRC The process as currently implemented at LaRC uses Pro Engineer for design Pro Manufacturing for fabrication PATRAN for model building and results visualiza tion NASTRAN for structural analysis SINDA 85 and P Thermal for thermal analysis and Code V for optical analysis At the present time the only analysis model that must be built manually is the Code V model all others can be imported from the Pro Engineer geometry The results from the thermal and structural analyses can be exported to Code V to produce optical an
23. e a standard graphics format and read this file into PATRAN The disadvantages to this method depend on the versions of software used They can involve rework in creating the solid form from the transferred surfaces and reconstruction of an assembly from the component parts due to loss of individual parts orientation during translation The third and optimal method is to import the geometry from a Pro Engineer part file directly into PATRAN This method is only viable for the releases of Pro Engineer above Version 10 and PATRAN 3 and above The geometry can then be either directly meshed or used to create a PATRAN solid model Options in Pro Engineer and P3 can be used to bring in simplified geometry automatically deleting details such as bolt holes or to create a mid plane shell geometry for a thin walled part Parts have also been imported into PATRAN from ANVIL but this brings across only the 2 D shape and position of parts The integration of design and analysis has several benefits In terms of streamlining the proc ess there is much less work to be done by the analyst since the majority of the geometry is im ported automatically The entire process of taking dimensions from a design drawing and manu ally building up the model geometry is eliminated Also the analyst is automatically working with the most current version of the design Eliminating the repeated step of manually entering the dimensions lessens the probability of errors in
24. e system that is compatible with the structural coordinate system taking care to ensure that the global origin is the same Code V allows the designer to specify an arbitrary global coordinate origin and convert the surfaces to global coordinates This can be accomplished with a macro an example of the macro required to translate from a relative to a global coordinate system is shown in Figure 2 Macro to convert a surface to a GLB global decentered surface ver n rfd 00 ver n 1055100 ins 5100 g 1 global origin Asurf num s 1 for s 2 surf x xsc s s gg y ysc s s g g z zsc s s g g a asc s s g g b bsc s s g g c csc s s g g glb s s g g xde s s x yde s s y zde s s z ade s s a bde s s b cde s s c sur s s end for ver y Figure 2 Macro for translation from relative to global coordinates The translation to global coordinates does impose some restrictions on the commands used to generate the optical design that the optical designer must take into account The primary restric tion is that the designer must use only basic tilts and decenters The time saving features such as BEN DAR RET and REV do not translate into their correct global coordinates and cannot be used The designer can use the GSC command to verify that the converted file matches the origi nal file Once the file has been converted to global coordinates it is written to a sequence file The
25. ed separately to the optical bench there is no way to ensure that the translations of the front and back surfaces of each element remain aligned In this particular model the connected nodes are attached to the optical deck by three rigid elements The structural analyst may select any method of attaching the nodes to the supporting structure The connection of the nodes to the supporting structure should simulate the stiffness of the optical mount The PATRAN user should keep all of the optical nodes together in a named component in PATRAN 2 5 or in a group in P3 This enables the user to easily specify these nodes in the results post processing phase The method for writing out the structural data from PATRAN in a format acceptable to the optical translator PATCOD is described in section 4 0 Structural analy sis be performed in any software that has link to read the results back into PATRAN or in any software that can mimic the output format described in section 4 0 The coordinate axes for the model should be as defined in section 3 0 The structural and optical analysts should commu nicate before the models are developed to ensure that these axes are acceptable Optical The typical optical design in Code V uses a relative coordinate system while the structural model uses a global coordinate system In order to easily transfer files between the two models the optical design needs to be converted to a global coordinat
26. ical Analysis for a description of assumptions relating to the coordinate axes of the model Output The output file generated by PATCOD will be a file with format identical to the input Code V file with the tilt and decenter values of each optical surface modified by the structural results This model file can be executed directly by the Code V analysis program in the same manner as the original model file During execution of PATCOD the user is given the option of changing or adding to the title of the Code V runstream PATCOD takes the root filename of the Code V input file and appends DEF SEQ where is a number from 1 to 9 allowing up to nine execution runs on the same Code V input file For example if the Code V filename is opticalrun seq the PATCOD output filename will be opticalrunDEF1 SEQ 5 0 Summary A concutrent engineering process involving electronic integration of design thermal and structural analyses and optical analysis has been developed at LaRC This process was developed by integrating existing design software Pro Engineer with modeling software PATRAN and thermal structural and optical analysis software SINDA 85 NASTRAN CODE V respec tively A new translator PATCOD was developed which electronically updates movements of optical components due to thermally or mechanically induced structural deflections The heart of the concurrent engineering process described here is the use of a single integrated m
27. in the model is desirable as is keeping the numbering se quential and simple Again the analysts should communicate to establish a method for record ing model related information One way to use the nodes and conductors created by PATRAN is to separate them into files that are called into the SINDA model using INCLUDE statements Thus the SINDA model can contain other data such as heating arrays if there is a change to the PATRAN model it will only affect the included files with the main SINDA model left unchanged The output of the PATRAN to SINDA translator is often quite bulky which makes editing of the full SINDA model difficult Using included files limits the size of the SINDA model file and allows several different SINDA files to reference the same PATRAN model If P3 Thermal is used all data are contained in the PATRAN model and there is usually no need for manual editing of files Structural The structural deflection translated to the optical model is only that due to the distortion of the optical bench or supporting structure and to deflections of the optical component mounts Currently distortions of a single optical component are not included in this translator Reasons for this are two fold 1 a detailed translator for single optical component distortion already exists between NASTRAN and Code V and 2 in the particular application for which this trans lator was developed the distortion of the supporting structure was the d
28. neer for de sign Pro Manufacturing for fabrication PATRAN for model building and results visualization NASTRAN for structural analysis SINDA 85 and P Thermal for thermal analysis and Code V for optical analysis Currently the only analysis model to be built manually is the Code V model all others can be imported from the Pro Engineer geometry The translator PATCOD was de veloped and tested at LaRC to transfer PATRAN results to Code V optical analysis software Directions for use of the translator are given 1 0 Background In many industries there has recently been a concerted movement toward quality manage ment and the issue of how to accomplish work more efficiently Part of this effort is focused on concurrent engineering the idea of integrating the design and analysis processes so that they are not separate sequential processes often involving design rework due to analytical findings but instead form an integrated system with smooth transfers of information Electronic integration of design and analysis processes was achieved and refined at Langley Research Center LaRC during the development of an optical bench for a laser based aerospace experiment One of the driving requirements for any complex optical system is its alignment stability under all conditions Accurate predictions of optical bench or test bed deflections are necessary to calculate beam paths and determine optical performance Another requirement increasingly
29. numbering schemes on a model the interpolated values were found to be correct The thermal results either from a steady state analysis or from time steps in a transient run can be read directly into PATRAN and the thermal results mapped 265 onto the model geometry For PATRAN 2 5 users the output file from SINDA is translated by SINPAT to produce element and nodal temperature files that can be read by PATRAN For P3 users either P3 Thermal or SINDA using the RSPT85 subroutine will produce nodal result files that are directly readable by P3 There are several methods available to import the nodal temperatures as actual thermal loads for the structural analysis rather than only for display For PATRAN 2 5 users the files must be run through a program called READER that translates the files to binary format The results can be interpolated onto the structural model using a built in utility of PATRAN TEMP ADD INT For users results from P3 Thermal or SINDA can be read into using the file import option The temperatures are read in as a nodal results file using the appropriate template This data can be displayed on the finite element model as a fringe plot This fringe plot is used to create a continuous FEM field to apply the nodal temperature data as a structural thermal load Also an option in PATQ the P3 thermal executable program allows users to map temperatures from one model to another with a differing mesh The latest
30. odel for thermal and structural analysis of a system This allows a saving of time in the thermal and struc tural analysis work since only one geometric model must be developed It facilitates electronic transfer of data between all types of analysis such as transfer of exact thermal gradients to be used in structural analysis It allows exact prediction of the optical performance based on calcu lated temperature distributions and deflections rather than global approximations Finally it produces greater model accuracy since the model can be directly imported from the design soft ware package 11 References 1 Oo Crouthamel M PAT SINDA Interface Guide PATRAN Division PDA Engineering March 1990 P3 Thermal Manual PATRAN Division PDA Engineering PDA Engineering PATRAN Plus User Manual Release 2 3 July 1988 p 22 25a Amundsen Ruth Some Useful Innovations with SINDA and TRASYS Fifth Annual Thermal and Fluids Analysis Workshop August 16 20 1993 Lewis Research Center Ohio Code V Reference Manual Optical Research Associates 3280 East Foothill Boulevard Pasa dena CA 91107 12 Appendix A PATCOD User s Guide Purpose The translator PATCOD is a FORTRAN 77 computer program developed at LaRC to read a typical Code V optical model input runstream It will update the decenter and tilt values with the correction values generated by a structural analysis program such as NASTRAN as printed from PAT
31. ominating factor The supporting structure is also the dominating factor in many common applications Each optical surface is modeled as an individual node in the structural model Some of the optical components may require several nodes to represent different locations on a single compo nent For example a lens that would normally only be a single node in PATRAN might require three surfaces in Code V front surface center back surface Each of these surfaces should then be a separate node in the PATRAN model positioned in the same locations as the Code V sur faces The connection between nodes should be rigid although it can simulate the coefficient of thermal expansion of the optical material if desired If the separate nodes comprising a single optical component are not structurally connected together or are modeled as a single node in PATRAN errors will arise in the translation of results to the optical model If the surfaces are modeled as a single node then the surfaces of the component will not remain aligned when the structural results are translated to Code V The reason for this is that any rotation of a two surfaced optical component such as a lens or beamsplitter imparts differing translations to the front and back surfaces With the component modeled as a single node the translations due to rotation will be the same which is not physically correct If the nodes are not connected together structurally but instead are each connect
32. ptical bench C 220222222 red Figure 5 Structural x deflections due to thermal load 9 Figure 6 Translation to optical code single optical beam path with 10 Figure 7 Sample relational file 16 Figure 8 Partial listing of sample run input file 17 Figure 9 Partial listing of sample run input file 17 Figure 10 Partial listing of Code V runstream file 18 Figure 11 Partial output of sample run file 8 0 19 Figure 12 Sample Execution Run of 20 Abstract Electronic integration of design and analysis processes was achieved and refined at Langley Research Center LaRC during the development of an optical bench for a laser based aerospace experiment Mechanical design has been integrated with thermal structural and optical analyses Electronic import of the model geometry eliminates the repetitive steps of geometry input to develop each analysis model leading to faster and more accurate analyses Guidelines for inte grated model development are given This integrated analysis process has been built around software that was already in use by de signers and analysts at LaRC The process as currently implemented uses Pro Engi
33. re e Plate elements that are to connect must have two identical corner nodes on the edge they share In PATRAN 2 5 no plate can attach to a solid element using less than four nodes In PATRAN 2 5 a plate attached to a solid element using four identical corner nodes will create a thermal conductor that does not include the conduction through the thickness of the plate An additional connection here must be constructed by the thermal analyst using a DFEG command to get the correct value In PATRAN 3 this problem does not arise since the finite element nodes are used as the nodes of the thermal model Thus in the case of a plate at tached to the face of a solid the nodes would coincide In PATRAN 2 5 all the material property values must be reset when the model is transferred between structural and thermal analysis because the thermal properties overwrite the struc tural properties and vice versa In P3 the properties are currently overwritten in a transfer between structural and thermal analysis this is slated to be improved in future versions In PATRAN 2 5 when three plates connect as a T a bar element must be added at the intersection to keep the thermal conduction correct Likewise when three bars connect as a T a point element must be added to keep the thermal conduction correct 22005 e The thermal analyst may need to reference either element or node numbers later in the thermal model a record of element numbers
34. te an ASCII file containing the node ID and displacement data The data is nodal rather than element results This option is chosen twice once for translational displacements and once for rotational displacements These report files are analysis code independent Any program that interfaces with P3 and has the option to calculate both translational and rotational displacements can interface with PATCOD PATCOD is tailored to read the prt files in their current format If the PATRAN 3 version is changed then subroutine READDEC must be changed to reflect any changes in prt file format A typical P3 text report file is shown in Figure 8 PATCOD is designed to skip records until the second word of a record is NODL The first word will be the integer node number that points to the structural node number in the PATHS DAT input file Words 3 to 5 floating point are the translation decenters in the translation file and rotational tilts in the rotation file There is a maximum imposed in the program of 2 000 nodes that may be referenced The file names will be entered at execution time After the prt files have been read into the program the user will be asked for the length units of the decenter data meters mm inches or feet This information will be used to ensure that all units are consistent See Figure 8 and Figure 9 for listings of prt files used in the sample case 3 File 4 A Code V input runstream optical model file
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