Internet Parallel Structure Analysis Program (IPSAP) User's Guide

Transcription

1 Internet Parallel Structure Analysis Program (IPSAP) User's Guide Version 1.8 Aerospace Structure Laboratory Seoul National University, Korea April 10, 2009

2 Chapter 1 Overview Internet Parallel Structure Analysis Program (IPSAP) is written by C, C++ and MPI. IPSAP is particularly suited for parallel numerical simulations involving large structures. In this type of computation, IPSAP dramatically reduces the time spent and the memory usage by solving a linear algebraic equations efficiently. IPSAP can be used for directly simulating a structural model with an input file written in the given definite form. Two main algorithms implemented in IPSAP are the Multifrontal Algorithm for static analysis and the Block Lanczos Iteration Algorithm with implicit restart out-of-core storage technique for vibration analysis. Both two algorithms are modified ones which are based on the element by element calling sequence which best fits for the well-known finite element method and distributed memory parallel technique based on use of BLAS, LAPACK(CLAPACK), METIS. 1.1 Feature of This Version 1. Element - Hexa8 : 8-node solid - Tetra4 : 4-node solid - Quad4 : 4-node shell - Tri3 : 3-node shell - Beam2 : 2-node beam 2. Property - PropSolid : solid property - PropShell : shell property - PropComp : shell property - PropBeam : beam property - PropBeamL : beam property 3. Material - Elastic3DIsotropic : 3 dimensional isotropic - Elastic3DOrthotropic : 3 dimensional orthotropic - Elastic2DIsotropic : 2 dimensional isotropic 1

3 - Elastic2DOrthotropic : 2 dimensional orthotropic - Elastic1D : 1 dimensional 4. LoadCase 5. Load - Force - Moment - Pressure - Global Acceleration - Nodal Temperature - Nodal Force 6. Analysis Type - LinearStatic : displacement - stress analysis - Vibration : frequency - normal mode analysis 7. ETC - Rigid Connection Element - Material Coordinate System - Many Kinds of Solution Parameters 1.2 Finite element implementation IPSAP provides three types of element - solid, shell, beam. All of them work on three dimensional space for general purpose. Solid element is classified into eight node hexahedron (Hexa8) and four node tetrahedron(tetra4) and shell element is separated three node triangle(tri3) and four node square(quad4). Beam element is Beam2. It will be described in chapter 5. 2

4 Chapter 2 Pre-requirement Depending on the pre-compiled versions of IPSAP, BLAS library may be required. 1 In addition, parallel version requires MPI (Message Passing Interface) such as LAM/MPI, MPICH or MSMPI. Even though IPSAP can be run with various kinds of BLAS library, we recommend for you to use BLAS by Kazushige Goto 2 in linux system and Intel Math Kernel Library(MKL) 3 in windows system for the best performance. In this time of release, for the users who do not have any kind of BLAS, every execution files are compiled statically. 1 LAPACK(CLAPACK) and METIS are statically linked in. 2 In IPSAP execution file for linux OS, GOTO is statically linked in. 3 In IPSAP execution file for windows OS, MKL is statically linked in. 3

5 Chapter 3 How to download The IPSAP can be downloaded from : Note that there are actually several pre-compiled single and parallel IPSAP executable files, depending on your machine architecture, operating system and MPI. See Table 3.1 for Windows and Table 3.2 for Linux operating system. As mentioned in the previous chapter, IPSAP used BLAS library named in the tables. Table 3.1 : IPSAP binary files for Windows CPU architecture BLAS MPI IPSAP executable 32-bit Single Intel MKL - IPSAP_single_x86.exe 64-bit Single Intel MKL - IPSAP_single_x64.exe 32-bit Parallel Intel MKL MS MPI IPSAP_parallel_x86.exe 64-bit Parallel Intel MKL MS MPI IPSAP_parallel_x64.exe Table 3.2 : IPSAP binary files for Linux CPU architecture BLAS MPI IPSAP executable 32-bit Single GOTO - IPSAP_single_x86.run 64-bit Single GOTO - IPSAP_single_x86_64.run 32-bit Parallel GOTO LAM/MPI MPICH2 IPSAP_parallel_x86.run IPSAP_parallel_x86_mpich2.run 64-bit Parallel GOTO LAM/MPI MPICH2 IPSAP_parallel_x86_64.run IPSAP_parallel_x86_64_mpich2.run 4

6 Chapter 4 How to run 4.1 Linux Operating System 1. IPSAP is statically compiled with GOTO blas library and does not require any additional library. 2. run IPSAP with the following command in a terminal $exec path/exec name input file 3. running parallel versions follows the same analogy $mpirun -np (N.P) exec path/exec name input file 4.2 Windows Operating System 1. IPSAP is statically compiled with Intel MKL library and does not require any additional library. 2. In the same way of linux OS as following command, you can run the program. $exec path/exec name input file 3. running parallel versions follows the same analogy $mpirun -np (N.P) exec path/exec name input file 5

7 Chapter 5 Format of Input file IPSAP input file has several control strings to distinguish each data set for finite element method. Table 5.1 shows typical input file. Each control string should be preceded by asterisk and written in uppercase. Brief descriptions are follows. Table 5.1 : The Example of IPSAP Input File TITLE IPSAP Input File Example'' NODE e e e e e e abbreviation -- PROPERTY PropShell MATERIAL Elastic2DIsotrpoic e ANALYSYSTYPE Vibration ELEMENT Quad abbreviation -- NSET NSET 2 81 BOUNDARY LOADCASE LOAD NodalForce ENDDATA OUTOPT default.out 1 END 6

8 5.1 TITLE TITLE string This is for the title or explanation of job and can be continued in new lines until next control string is reached. 5.2 NODE NODE NID X-Coordinate Y-Coordinate Z-Coordinate NID X-Coordinate Y-Coordinate Z-Coordinate NID(node id) does not need to be in order, but each coordinate should be global data. Notice that NID should not be duplicated. 5.3 ELEMENT ELEMENT type Regardless of element type, all elements require EID(element id), PID(property id) and connectivity. Depending on element type, IPSAP requires different information in different format. The format and element coordinate system are as below(see Figure 5.1). The data for one element should be written in one line. 1. Beam2 'Beam2' requires two NID's for connectivity and one vector which is located in the plane made by r-axis and s-axis. It is also with respect to global coordinate system. The vector is used to determine the beam's element coordinate. ELEMENT Beam2 EID PID NID NID X-coord Y-coord Z-coord EID PID NID NID X-coord Y-coord Z-coord 2. Hexa8 'Hexa8' is 8 nodes hexahedron solid element and therefore requires eight NID's for connectivity within one line. ELEMENT Hexa8 EID PID NID NID NID NID EID PID NID NID NID NID 3. Tetra4 'Tetra4' is four nodes tetrahedron element and requires four NID's. 7

9 Figure 5.1 : Natural Coordinate System of Element ELEMENT Tetra4 EID PID NID NID NID NID EID PID NID NID NID NID 4. Tri3 'Tri3' is three nodes shell element and requires three NID's. In addition, theta or MCID and offset is defined. theta means material property orientation angle in degrees and MCID means material coordinate system identification number. And offset means offset value from the surface of grid points to the element reference plane. ELEMENT Tri3 EID PID NID NID NID EID PID NID NID NID theta or MCID theta or MCID offset offset 5. Quad4 'Quad4' is 4 nodes shell element and requires four connectivities. There are also defined theta or MCID and offset. The meaning of theta or MCID and offset of Quad4 is same with Tri3. 8

10 ELEMENT Quad4 EID PID NID NID NID NID EID PID NID NID NID NID theta or MCID theta or MCID offset offset 6. Elast0 This defines zero dimensional spring element. 'Elast0' requires one NID and one DOFID of NID. ELEMENT Elast0 EID PID NID DOFID EID PID NID DOFID 7. Elast1 This defines one dimensional spring element. 'Elast1' requires two NIDs and two DOFIDs of NIDs. And PID is related with PropElast in PROPERTY. ELEMENT Elast1 EID PID NID1 DOFID1 NID2 DOFID2 EID PID NID1 DOFID1 NID2 DOFID2 5.4 PROPERTY 'Property' defines geometric features of structures. Regardless of kind of property, all properties require PID(property id) and MID(material id). Depending on structural dimension, IPSAP requires different PROPERTY type information in different format. The data for one property should be written in one line. 1. PropSolid 'PropSolid' requires basically PID and MID because all geometric features of solid elements can be obtained from the locations of nodes. In addition, MCID is required. MCID defines the material property coordinate system. PROPERTY PropSolid PID MID (MCID) PID MID (MCID) 2. PropShell 'PropShell' requires basically two parameters which are MID and thickness. In addition, for considering bending moment and transverse shear, MID1 and MID2 is defined. bfact and sfact each mean the bending moment of inertia ratio and transverse shear thickness ratio and default values are each 1 and

11 And nsm defines nonstructural mass per unit area. PROPERTY PropShell PID MID thickness (MID1) (bfact) (MID2) (sfact) (nsm) PID MID thickness (MID1) (bfact) (MID2) (sfact) (nsm) 3. PropComp 'PropComp' defines the property of n-ply composite material laminate and requires PID, nsm, MIDi, Ti and thetai. PROPERTY PropComp PID nsm MID1 T1 theta1 MID1 T1 theta1 PROPERTY PropComp PID nsm MID1 T1 theta1 MID1 T1 theta1 4. PropBeam 'PropBeam' requires five more parameters which are A(cross-section area), three area moments of inertia(j, I ss, I tt ) and κ (shear effect factor). If I tt is not given, it is assumed to be equal to I ss. κ is generally about 5/6 and if κ is not given, the beam is assumed to be consistent with classical bending theory. And nsm defines nonstructural mass per unit area. PROPERTY PropBeam PID MID A J I ss (I tt ) ( κ ) (nsm) PID MID A J I ss (I tt ) ( κ ) (nsm) 5. PropBeamL 'PropBeam' defines the property of a beam element by cross-sectional dimensions. In IPSAP, six beam libraries are defined and these are ROD, TUBE, BAR, BOX, T1, L. By these dimensions of each beam library, A, J, I ss, and I tt are defined. PROPERTY PropBeamL PID MID DIM1 DIM2 DIM3 ( κ ) (nsm) PID MID DIM1 DIM2 DIM3 ( κ ) (nsm) 10

12 5. PropElast 'PropElast' specifies the stiffness of a scalar elastic(spring) element, Elast0 and Elast1 PROPERTY PID PID PropElast K K 5.5 MATERIAL MATERIAL type IPSAP provides only elastic material which can be classified according to directional symmetry and dimension. The data for one material should be written in one line. All materials have MID(material id), CID(coordinate id), elastic modulus, density and thermal expansion coefficients. If the density is not given, it is set 0.0. Detailed formats are as follows. 1. Elastic3DIsotropic 'Elastic3DIsotropic' is referenced by PropSolid and requires E(Young's modulus), ν (Poisson's ratio), ρ (density) and α (thermal expansion coefficient). MATERIAL Elastic3DIsotropic 11

13 MID E ν ( ρ ) ( α ) MID E ν ( ρ ) ( α ) 2. Elastic3DOrthotropic 'Elastic3DOrthotropic' is referenced also by PropSolid and requires more parameters than the isotropic case due to the directional differences in elastic moduli and thermal characteristics. MATERIAL Elastic3DOrthotropic MID E 1 E 2 E 3 ν 12 ν 23 ν 31 G 12 G 23 G 31 ( ρ ) ( α 1 ) ( α 2 ) ( α ) 3 MID E 1 E 2 E 3 ν ν ν 31 G 12 G 23 G 31 ( ρ ) ( α 1 ) ( α 2 ) ( α ) 3 3. Elastic2DIsotropic 'Elastic2DIsotropic' is a 2-dimensional version of 3D-Isotropic material and therefore referenced by PropShell. MATERIAL Elastic2DIsotropic MID E ν ( ρ ) ( α ) MID E ν ( ρ ) ( α ) 4. Elastic2DOrthotropic 'Elastic2DOrthotropic' is a 2-dimensional version of 3D-Orthotropic material and therefore referenced by PropShell. MATERIAL Elastic2DOrthotropic MID E 1 E 2 12 ν G 12 G 23 G 31 ( ρ ) ( α 1 ) ( α 2 ) MID E 1 E 2 ν 12 G 12 G 23 G 31 ( ρ ) ( α 1 ) ( α 2 ) 5. Elastic1D 'Elastic1D' is referenced by PropBeam. MATERIAL Elastic1DIsotropic MID E ν ( ρ ) ( α ) MID E ν ( ρ ) ( α ) 5.6 COORD Coordinate system in IPSAP is used only for material coordinates. All coordinates have CID(coordinate id) and three directional vectors which de_ne the x, y and z axis of new Cartesian coordinate system. The directional vectors are not required to have the magnitude of unity, but should be orthogonal with each other. It is notable that CID should be larger than zero because zero CID in the material control string designates the global reference coordinate. COORD 12

14 CID CID x X x Y x Z y X y Y y Z z X z Y z Z z x X x Y x Z y X y Y y Z z X z Y Z 5.7 ANALYSISTYPE ANALYSISTYPE LinearStatic integer integer ANALYSISTYPE Vibration integer integer integer integer integer Analysis type is one of LinearStatic and Vibration. According to the analysis type, the number of option is different. 'LinearStatic' need 2 options and 'Vibration' needs 5. The description is as follows: LinearStatic Element Block Size, Communication Block Size Vibration Element Block Size, Communication Block Size, Number of Eigen Value, Lanczos Block Size, Maximum Number of Block. Element Block Size controls the entire performance of solver. Generally one of the values 4, 8, 16, 32 will be moderate. Communication Block Size controls the parallel performance. The performance will be maximized around the value from 64 to 256, but too large value may induce failure of the program during the parallel job. In the case of failure, some smaller values(4,8,16,32) of communication block size is recommended. Vibration analysis mode of IPSAP computes eigenvalues from the first mode to N th mode. N is set by the third option of vibration analysis type, Number of Eigen Value. Lanczos Block Size is the number of Lanczos vectors which is handled during one Lanczos iteration. Commercial codes such as NASTRAN and ABAQUS set the default value of Lanczos block size 7. Maximum Number of Block option in Vibration analysis controls the maximum size of Lanczos block tridiagonal matrix which is defined by Maximum Number of Block x La nczos Block Size. From the experiences, the following condition is recommended for the performance of program. Maximum Number of Block x Lanczos Block Size > 4 x Number of EigenValue 5.8 NSET NSET is to define the boundary condition, nodal force and temperature. If NID's are continuous, TO keyword can be used. For example, may be replaced by 1 TO 4 NSET NSID Node ID NID NID NID NID NID NSET NSID Node ID NID NID NID NID NID. 5.9 BOUNDARY 'Magnitude' can be used for pre-described displacement boundary. For example if it is zero, then it means fixed boundary. 'Direction' is to give direction of displacement. The 13

15 number from 1 to 6 are used to represent translation(1,2,3) and rotation(4,5,6). BOUNDARY BID NSID Magnitude Direction BID NSID Magnitude Direction 5.10 LOADCASE LOADCASE LCID LID LID LID LID This option defines several loads to be used in one load case LOAD LOAD type According to the 'Load type', there are three choices, NodalForce, Acceleration and Temperature as below. 1. Force 'Force' is defined by X, Y and Z directional force. LOAD Force LID NID X-dir. Force Y-dir. Force Z-dir. Force 2. Moment 'Moment' is defined by X, Y and Z rotational force, moment. LOAD Moment LID NID X-dir. Moment Y-dir. Moment Z-dir. Moment 3. Pressure Pressure can be used on 2D Element, Tri3 and Quad4. LOAD Pressure LID EID Magnitude 4. Acceleration Acceleration is used for inertial load acting on the entire model such as the structure is under accelerating condition. LOAD Acceleration X-dir. Acceleration Y-dir. Acceleration Z-dir. Acceleration 5. Temperature Temperature load is active only if the elements which the node set is belonged 14

16 to have thermal expansion coefficients. LOAD Temperature LID NSID Temperature 6. NodalForce 'NodalForce' has the same form as 'BOUNDARY' control string. But, the usage of this keyword is not recommended. Instead of this keyword, Force and Moment keywords are newly involved. LOAD NodalForce LID NSID Magnitude Direction 5.12 RCON 'RCON' is the rigid connection between nodes like a stiff beam. The first IDNID is independent node and CM means component numbers of the dependent degrees of freedom in the global coordinate system at Node ID, DNIDi. Hense the others following DNIDis mean dependent nodes. RCON RCID IDNID CM DNID1 DNID2 RCON RCID IDNID CM DNID1 DNID ENDDATA 'ENDDATA' is a delimiter between model data and additional data. Therefore, additional data control strings follow OUTOPT In LinearStatic analysis, OUTOPT file-name 0 or 1 0 or 1 0 or 1 In Vibration analysis, OUTOPT file-name 0 or 1 0 or 1 This control string provides output format. file-name' designates the name of the output file which IPSAP will generate. The last two or three integers control the kind of output data. If IPSAP runs on LinearStatic analysis mode, information of original finite element model, displacement and stress will be written or not on file you named according to the choice of the field's value(0 or 1). For example, if you choose 0 in the first integer field, it means simply 'Do not write information of initial finite element model'. In the case of Vibration analysis, two fields, information of original finite element model and eigenvector will be referenced and the eigenvectors will be written or not according to the second field's value(0 or 1). If this control string does not appear in the input file, IPSAP generates a file named 'default.out' and assumes that all integer fields are on(1) such that the disp 15

17 lacement and the stress are written in the file EXPOPT EXPOPT Memory1 Memory2 initial shift Convergence criteria IPSAP provides expert user's mode to control memory usage, initial shift and convergence criteria. Memory1 assigns MBytes of memory for factorized frontal data, which will be stored in a disk storage if EXPOPT is not used. In the case of LinearStatic analysis mode, only Memory1 will be referenced. Memory2 assigns memory for Lanczos vectors in the same way of Memory1. Initial Shift will be efficient for a eigenvalue analysis model with insufficient boundary conditions and the recommendation is negative value. For the convergence criteria field, machine precision is used in general. If you are not sure, do not use 'EXPOPT' control string TEMPDIR TEMPDIR Temporary directory path 'TEMPDIR' let you choose temporary directory where IPSAP dump file is written instead of default current directory END 'END' means the end of all data. 16

18 Chapter 6 Format of Output file and Visualization 6.1 Format of Output Figure 6.1 and Figure 6.2 show the example of output file format. IPSAP RESULT FILE - LinearStatic ANALYSIS NID and EID ARE SORTED ONES! NODE 3362 NID X Y Z e e e e e e ELEMENT 1600 EID TYPE NID Tetra Tetra DISPLACEMENT NID U V W Rx Ry Rz e e e e e e NODAL FORCE APPLIED TO 1,2-DIMENSIONAL ELEMENT EID Fz Fy Fz Mx My Mz e e e e e e e e e e e e STRESS AVERAGE AT NODE BELONGING TO 3-DIMENSIONAL ELEMENT NID Sxx Syy Szz Sxy Syz Szx e e e e e e e e e e e e-01 Figure 6.1 : Output file format (Linear Static) 17

19 IPSAP RESULT FILE - Vibration ANALYSIS NID and EID ARE SORTED ONES! NODE 3362 NID X Y Z e e e e e e ELEMENT 1600 EID TYPE NID Tetra Tetra EIGENVALUE ANALYSIS SUMMARY 10 MODE 1 eigenvalue : e+05 MODE 1 eigenvalue : e MODE 1 eigenvalue : e+05 NID U V W Rx Ry Rz e e e e e e e e e e e MODE 2 - eigenvalue : e+05 NID U V W Rx Ry Rz e e e e e e e e e e e Figure 6.2 : Output file format (Vibration) 6.2 Visualization DIMAOND/IPSAP is the own visualization tool of IPSAP. By DIAMOND/IPSAP, you can enjoy the structure analysis. 18