🏗️ Professional Truss Suite (2D)

A Pedagogical & Commercial-Grade Structural Analysis Tool

Developed by Mr. D Mandal, Assistant Professor, Department of Civil Engineering, KITS Ramtek.

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📖 Software Overview

The Professional Truss Suite is an interactive, web-based environment for the linear static analysis of 2D trusses using the Direct Stiffness Method (DSM).

Unlike commercial "black-box" software (like SAP2000 or STAAD.Pro) that hides the underlying mathematics, this application is designed as a "Glass-Box" educational tool. It explicitly bridges the gap between finite element theory and computational execution, allowing students to observe the formulation of local and global stiffness matrices in real-time.

📌 Benchmark note: The built-in 9-Member Pratt Truss Benchmark applies 300 kN downward at Node 5 and 10 kN horizontal at Node 4, reproducing Table 2 of the published paper (Mandal, 2026, CAEE, 10.1002/cae.70183).

✨ Key Features

• 🎓 Educational "Glass-Box" Engine: View step-by-step mathematical formulations including the $4 \times 4$ element stiffness matrices ($k$), the fully assembled unpartitioned global matrix ($K_{global}$), and the reduced partitioned system ($K_{ff} \cdot U_f = F_f$).
• 📊 Dynamic Free-Body Diagrams (FBD): Renders high-fidelity, interactive Plotly graphics displaying undeformed geometry, dynamically scaled load arrows, and separated horizontal/vertical support reaction vectors ($R_x$, $R_y$).
• 🔄 Real-Time Unit Scaling: Seamlessly toggle the visual output between Newtons (N), Kilonewtons (kN), and Meganewtons (MN) without altering the base SI solver engine.
• 📝 1-Click Professional Reporting: Automatically generates a comprehensive .pdf calculation report containing software metadata, embedded high-resolution graphics, nodal displacements, and categorized member forces.
• 🛡️ Mathematical Bulletproofing: Includes strict physics validation (intercepts zero-length members, negative materials) and pre-solve condition number checks to identify structurally unstable mechanisms.

📐 Engineering Methodology

The core solver relies on standard matrix structural analysis:

1. Local Stiffness Formulation: Calculates $k_{local}$ using standard trigonometric transformations ($c = \cos\theta, s = \sin\theta$).
2. Global Assembly: Vectorized mapping of local DOFs to assemble the $2n \times 2n$ Global Stiffness Matrix.
3. Boundary Conditions: Partitions the matrix into free and restrained DOFs to solve for unknown displacements.
4. Internal Forces: Extracts member axial forces, automatically tagging them as Tension (Positive/Blue) or Compression (Negative/Red).

🚀 Installation & Local Setup

Prerequisites

• Python 3.9 or newer.

Instructions

1. Clone the repository:

   git clone https://github.com/mdaipayan/Truss_app.git
   cd Truss_app

2. Install dependencies:

   pip install -r requirements.txt

3. Run the application:

   streamlit run app.py

📚 How to Cite

If you use the Professional Truss Suite in your teaching, research, or structural analysis projects, please cite the official publication in Computer Applications in Engineering Education:

Mandal, D. (2026). Development of an interactive web-based tool for 2D truss analysis using the direct stiffness method. Computer Applications in Engineering Education, 34(3), e70183. https://doi.org/10.1002/cae.70183

BibTeX

@article{mandal2026truss,
  title={Development of an interactive web-based tool for 2D truss analysis using the direct stiffness method},
  author={Mandal, Daipayan},
  journal={Computer Applications in Engineering Education},
  volume={34},
  number={3},
  pages={e70183},
  year={2026},
  publisher={Wiley},
  doi={10.1002/cae.70183},
  url={https://doi.org/10.1002/cae.70183}
}