Supported Elements

AbaqusReader.jl supports 60+ ABAQUS element types across multiple categories. Element variants (e.g., C3D8R, C3D8H) with the same node count map to the same generic element type, as the package focuses on mesh topology rather than analysis-specific details like integration schemes.

3D Solid Elements

Tetrahedral Elements

Wedge/Prism Elements

Hexahedral (Brick) Elements

Cohesive Elements

Shell Elements

Triangular Shells

Quadrilateral Shells

2D Continuum Elements

Plane Stress (CPS)

For structures where stress in one direction is negligible (thin plates loaded in their plane).

Plane Strain (CPE)

For structures with no strain in one direction (long structures with uniform cross-section).

Axisymmetric (CAX)

For rotationally symmetric structures and loading.

Beam and Truss Elements

Element Suffix Meanings

Understanding the suffix letters helps in selecting the right element:

• R = Reduced integration - Fewer integration points, faster computation, may need finer mesh to avoid hourglassing in first-order elements
• H = Hybrid formulation - Independent pressure interpolation for nearly incompressible or fully incompressible materials
• I = Incompatible modes - Enhanced for better bending behavior, eliminates parasitic shear stresses
• M = Modified formulation - Improved performance with minimal locking, works well in contact problems
• E = Enhanced strain - Improved formulation for certain applications

Quick Selection Guide

• Need accuracy with coarse mesh? Use second-order elements (10, 15, 20, 8 nodes)
• Need computational efficiency? Use reduced integration (R suffix) with adequate mesh density
• Nearly incompressible material? Use hybrid elements (H suffix)
• Bending-dominated problem? Consider incompatible modes (I suffix) or second-order elements
• Contact analysis? Consider modified elements (M suffix, e.g., C3D10M)
• Avoid first-order triangles and tets (C3D4, CPS3, CPE3, CAX3) except as filler elements

Adding New Element Types

Adding support for new ABAQUS element types is straightforward - element definitions are stored in a TOML database file rather than in code. See the Contributing Guide for detailed instructions.

Handling Unknown Element Types

If you encounter an ABAQUS element type that is not yet in the database, AbaqusReader will provide a clear error message with instructions on how to proceed.

Dynamic Registration (Quick Fix)

For immediate use, you can register an element type dynamically before reading your mesh:

using AbaqusReader

# Register a C3D10I element (10-node incompatible mode tetrahedron)
register_element!("C3D10I", 10, "Tet10")

# Now you can read meshes containing C3D10I elements
mesh = abaqus_read_mesh("model_with_c3d10i.inp")

The register_element! function takes three arguments:

• element_name: The ABAQUS element name (case-insensitive, will be uppercased)
• num_nodes: Number of nodes in the element
• element_type: The generic topology type (e.g., "Tet4", "Hex8", "Tri3", "Quad4", "Seg2")

This is useful when:

• You need to quickly process a file with an uncommon element variant
• You're testing or prototyping
• You don't want to modify the package source

Permanent Addition (Recommended)

For element types that should be permanently available:

1. Edit data/abaqus_elements.toml in the AbaqusReader.jl repository

2. Add a new section following the existing format:

   [ELEMENT_NAME]
   nodes = <number_of_nodes>
   type = "<topology_type>"
   description = "Element description from ABAQUS documentation"

3. Run tests to verify: julia --project=. test/runtests.jl

4. Submit a pull request to https://github.com/ahojukka5/AbaqusReader.jl

See Issue #67 for the discussion that led to this feature.

Common Element Variations

ABAQUS uses many variations of standard elements with the same node layout but different analysis characteristics:

• Integration variations: C3D8 vs C3D8R (full vs reduced integration)
• Material model variations: C3D8 vs C3D8H (standard vs hybrid for incompressible materials)
• Formulation variations: C3D8 vs C3D8I (standard vs incompatible modes)
• Physics variations: CPS4 vs CPE4 (plane stress vs plane strain)

Since AbaqusReader focuses on mesh topology rather than analysis formulations, these variations with the same node count map to the same generic element type. The specific ABAQUS element name is preserved in the parsed data for reference.