**RSICC CODE PACKAGE PSR-430**

**1. NAME AND TITLE**

ORMGEN3D: Finite Element Mesh Generator for 3-D Crack Geometries.

**2. CONTRIBUTORS**

Oak Ridge National Laboratory, Oak Ridge, Tennessee, through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

Fortran; CRAY X-MP (P00430CY0MP00).

**4. NATURE OF PROBLEM SOLVED**

ORMGEN3D is a finite element mesh generator for computational fracture mechanics analysis. The program automatically generates a three-dimensional finite element model for six different crack geometries. These geometries include flat plates with straight or curved surface cracks and cylinders with part-through cracks on the outer or inner surface. Mathematical or user-defined crack shapes may be considered. The curved cracks may be semicircular, semielliptical, or user-defined. A cladding option is available that allows for either an embedded or penetrating crack in the clad material.

**5. METHOD OF SOLUTION**

In general, one-eighth or one-quarter of the structure is modeled depending on the configuration or option selected. ORMGEN generates a core of special wedge or collapsed prism elements at the crack front to introduce the appropriate stress singularity at the crack tip. The remainder of the structure is modeled with conventional 20-node isoparametric brick elements. Element group I of the finite element model consists of an inner core of special crack tip elements surrounding the crack front enclosed by a single layer of conventional brick elements. Eight element divisions are used in a plane orthogonal to the crack front, while the number of element divisions along the arc length of the crack front is user-specified. The remaining conventional brick elements of the model constitute element group II.

**6. RESTRICTIONS OR LIMITATIONS**

Maxima of 5500 nodes and 4 layers of clad elements.

**7. TYPICAL RUNNING TIME**

NESC executed all sample problems in 2.2 CP seconds on a Cray Y-MP/832.

**8. COMPUTER HARDWARE REQUIREMENTS**

ORMGEN3D required 263,000 words of memory on a Cray Y-MP/832 for execution.

**9. COMPUTER SOFTWARE REQUIREMENTS**

UNICOS 5.1 and a Fortran 77 compiler are required.

**10. REFERENCES**

B. R. Bass and J. W. Bryson, "Applications of Energy Release Rate Techniques to Part-Through Cracks in Plates and Cylinders, Volume 1. ORMGEN-3D: A Finite Element Mesh Generator for 3-Dimensional Crack Geometries," NUREG/CR-2997 Volume 1 (ORNL/TM-8527/V1) (December 1982).

User Instruction Updates, Version 3.0 (September 23, 1988).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one DS/HD diskette on which the Fortran source and test cases are written in DOS format.

**12. DATE OF ABSTRACT**

August 1999.

** KEYWORDS:** FRACTURE MECHANICS; MESH GENERATION