NESC0581 SLADE-D
SLADE-D, Transient Dynamic Response of Elastic Shells by Finite Elements Method
NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHORS, MATERIAL, CATEGORIES
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| Program name | Package id | Status | Status date |
|---|---|---|---|
| SLADE-D | NESC0581/01 | Tested | 01-NOV-1975 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NESC0581/01 | IBM 370 series | IBM 370 series |
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7. UNUSUAL FEATURES OF THE PROGRAM
SLADE-D is designed for the dynamic analysis of thin shells. A doubly-curved, arbitrary quadrilateral element is utilized. The element is based on a minimum potential energy principle for thin shells. A simple central- difference time integration scheme together with a diagonal mass matrix is used to compute the transient dynamic response. Since the majority of aerospace structures are based on shells of revolution, the program is designed specifically for a shell the reference surface of which is a portion of an axisymmetric surface. The program allows up to five separate layers and up to five separate elastic anisotropic materials with temperature-dependent properties. SLADE-D handles variable-thickness shells and allows thickness discontinuities along element boundaries. It provides for both normal and tangential surface loads and for temperature changes through the thickness as well as varying temperatures over the reference surface. Over any portion of the boundary, a choice of thirteen separate boundary conditions is available. To ease data preparation, simple but effective generation schemes are built into the program. SLADE-D computes dynamic deformations, velocities, stresses, and stress resultants occurring in the shell. Since it is designed for use by a large number of people, it contains error checks wherever possible and, except where needed for efficiency, very straightforward logic. SLADE-D uses a single dimensioned storage array for the total stiffness matrix, mass matrix, and load vector. If a given problem fits within the limits of this storage array, the program functions as an in-core program. If additional storage is required, the program seeks on-line auxiliary storage which must be randomly accessible.
SLADE-D is designed for the dynamic analysis of thin shells. A doubly-curved, arbitrary quadrilateral element is utilized. The element is based on a minimum potential energy principle for thin shells. A simple central- difference time integration scheme together with a diagonal mass matrix is used to compute the transient dynamic response. Since the majority of aerospace structures are based on shells of revolution, the program is designed specifically for a shell the reference surface of which is a portion of an axisymmetric surface. The program allows up to five separate layers and up to five separate elastic anisotropic materials with temperature-dependent properties. SLADE-D handles variable-thickness shells and allows thickness discontinuities along element boundaries. It provides for both normal and tangential surface loads and for temperature changes through the thickness as well as varying temperatures over the reference surface. Over any portion of the boundary, a choice of thirteen separate boundary conditions is available. To ease data preparation, simple but effective generation schemes are built into the program. SLADE-D computes dynamic deformations, velocities, stresses, and stress resultants occurring in the shell. Since it is designed for use by a large number of people, it contains error checks wherever possible and, except where needed for efficiency, very straightforward logic. SLADE-D uses a single dimensioned storage array for the total stiffness matrix, mass matrix, and load vector. If a given problem fits within the limits of this storage array, the program functions as an in-core program. If additional storage is required, the program seeks on-line auxiliary storage which must be randomly accessible.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
The
stiffness matrix, mass matrix, and load vector generated are stored in A, a one-dimensional array of 6056 locations. If the matrices and vector generated require more than 6056 core locations, either random access extended core storage, random access mass storage disk files, or the equivalent is required. As the program is currently written, the mass storage calls WRITEC and READEC are used in conjunction with a CDC6635 extended core storage unit, and the mass storage calls OPENMS, WRITMS, and READMS are used in conjunction with the system disk files.
The required number of blocks needed to store the stiffness matrix, mass matrix, and load vector is set up as one file of information in extended core storage or in disk file storage. Extended core storage is sought first, and, if the file length exceeds the space available, the file is placed in disk storage. Each block comprises 6056 core locations, located in the array A when in the core of the computer. The mass storage calls allow any number of words to be transferred to or from the file starting at any point in the file. The result is a randomly-accessible file. Any block is accessible at any time. The random access feature is required in the assembly of the stiffness matrix, mass matrix, and load vector in MERGEX. The time integration in INTEGX uses the file sequentially.
The
stiffness matrix, mass matrix, and load vector generated are stored in A, a one-dimensional array of 6056 locations. If the matrices and vector generated require more than 6056 core locations, either random access extended core storage, random access mass storage disk files, or the equivalent is required. As the program is currently written, the mass storage calls WRITEC and READEC are used in conjunction with a CDC6635 extended core storage unit, and the mass storage calls OPENMS, WRITMS, and READMS are used in conjunction with the system disk files.
The required number of blocks needed to store the stiffness matrix, mass matrix, and load vector is set up as one file of information in extended core storage or in disk file storage. Extended core storage is sought first, and, if the file length exceeds the space available, the file is placed in disk storage. Each block comprises 6056 core locations, located in the array A when in the core of the computer. The mass storage calls allow any number of words to be transferred to or from the file starting at any point in the file. The result is a randomly-accessible file. Any block is accessible at any time. The random access feature is required in the assembly of the stiffness matrix, mass matrix, and load vector in MERGEX. The time integration in INTEGX uses the file sequentially.
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NESC0581/01
| File name | File description | Records |
|---|---|---|
| NESC0581_01.001 | PROGRAM SOURCE (F4) | 3507 |
| NESC0581_01.002 | SAMPLE PROBLEM DATA | 61 |
| NESC0581_01.003 | SAMPLE PROBLEM PRINTED OUTPUT | 637 |
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- I. Deformation and Stress Distributions, Structural Analysis and Engineering Design Studies
Keywords: deformation, finite element method, matrices, mechanical structures, shells, stresses.