The meshrs addresses the interoperability gap between proprietary simulation software, academic codes, and in-house solvers by developing a modular framework in the Rust programming language. The framework enables the conversion of proprietary mesh formats (such as COMSOL .mphtxt and Abaqus .inp) to the open-standard VTU format for visualization in ParaView, while providing extensible modules for user-defined pre-processing analysis. Key contributions include mesh quality assessment using metrics like Jacobian ratio and skewness, integration point optimization based on material properties and a user-defined error tolerance, and deformation visualization of raw result data from .txt files. By leveraging Rust's memory safety, performance characteristics, and growing industry adoption, this work establishes a foundation for reliable, high-performance engineering software tools that bridge legacy systems and modern development practices.

• Parsing

  • Supports .inp (Abaqus) and .mphtxt (COMSOL) file formats for mesh parsing and .txt file format for nodal value parsing.

• Analysis

  • Calculates geometric quality metrics, including:
    • Knupp's algebraic quality metrics (Shape Metric, Skewness Metric, Length Ratio, Orientation Metric, Volume Metric)
    • Determinant check
    • Jacobian Ratio

• Optimization

  • Performs mass and stiffness matrix integration optimization of Gaussian quadrature points.

• Output

  • Generates VTU files compatible with ParaView for intuitive visualization.
  • Generates TXT files for detailed analysis.

To get started with the meshrs, clone this repository and use Cargo (Rust's package manager) to build the project. Run the following commands:

git clone https://github.com/tiagomrns/meshrs.git
cd meshrs
cargo build --release

Below are various use cases for the tool:

1. Basic Mesh Parsing
   Generate a VTU representation of a COMSOL mesh file:

   cargo run --release -- mesh.mphtxt

2. Geometric Quality Analysis Perform mesh quality analysis for an Abaqus mesh file:

   cargo run --release -- model.inp --analyze-mesh

3. Gaussian Quadrature Optimization (Mass Matrix Integration)
   Optimize Gaussian integration points for the mass matrix:

   cargo run --release -- input_mesh.inp --optimize-gauss --gauss-tolerance 1e-4 --mass-integration --material-property 10.0,5.0,3.0,0.5

4. Gaussian Quadrature Optimization (Stiffness Matrix Integration)
   Optimize Gaussian integration points for the stiffness matrix using provided material property for 3D mesh (6 at the beginning shows that the material matrix is 6x6):

   cargo run --release -- input_mesh.inp --optimize-gauss --stiffness-integration --material-property '6;10.0;1.3;4.0;0.6;1.0;0.3;1.3;0.8;0.3;0.1;0.5;0.7;4.0;0.3;0.7;0.2;0.8;0.4;0.6;0.1;0.2;0.9;0.0;0.1;1.0;0.5;0.8;0.0;0.6;0.1;0.3;0.7;0.4;0.1;0.1;0.3'

The tool generates the following output files for further analysis:

1. Define a new ElementType:

   • Open structs_and_impls.rs.
   • Add a new variant to the ElementType enum.

2. Shape Functions:

   • Implement the get_shape_functions method for your new ElementType.

3. Integration Rules:

   • Extend the implementation in gaussian_quadrature.rs to define symbolic or numerical integration rules.

1. Create a New Parser Module:

   • Add your parser under the src/parser directory.
   • Implement the necessary parsing logic (see abaqus_inp.rs).

2. Connect Parser:

   • Register your parser in parser/mod.rs.

• Hardcoded Output Path:

  • The output directory is currently hardcoded in main.rs.
  • Action for Users: You must manually modify the output_dir variable in main.rs to match your local file system before running the tool. Failure to do so may result in the program panicking due to an invalid path.

• High Order Shape Functions and Derivatives:

  • Shape functions for Quadratic Hexahedron, Biquadratic Hexahedron, and Triquadratic Hexahedron require verification before use.
  • Action for Users: Please review the implementation in structs_and_impls.rs if utilizing these specific element types for high-precision simulations.

• Symbolic Integration Approximations:

  • The symbolic math engine used in the tool has limitations when handling non-polynomial functions such as rational functions and square roots.

  • Issue: The following critical calculations rely on a Taylor Series expansion:

    • Calculation of the Inverse Jacobian (required for Stiffness Matrix in both square and non-square cases).
    • Computation of the Metric Determinant (required for Mass Matrices with non-square Jacobians).

  • Consequence:

    • Using Taylor Series introduces approximation errors, which can accumulate during stiffness matrix calculations, leading to less precise results.

  • Future Solution:

    • Replace the Taylor Series expansion with Chebyshev Interpolation or alternative polynomial interpolation methods to better approximate non-polynomial terms. This enhancement would significantly reduce numerical errors in the calculation process.

This README provides an overview of the meshrs, summarizing its capabilities, installation, usage, known limitations, and guidelines for extending its functionality.