# Refined Activity Diagram: Interleaved Experimental & Modeling Strategy

This diagram details a concrete, iterative workflow for material research that tightly integrates experimental campaigns and modeling, focusing on the calibration and validation of material models using a sequence of well-designed tests and scenarios.

## Process Description

1. **Experimental Campaign**
   - Start by incorporating a new binder system and preparing specimens.
   - Conduct standard compression tests (CT) under monotonic (LS1) and fatigue (LS4) loading scenarios.
   - Acquire experimental data on strength and fatigue behavior.

2. **Model Calibration**
   - Use the CT data to calibrate two types of material models:
     - Discrete Model (DM)
     - Microplane Model (MS)

3. **Advanced Experimental Procedures**
   - Perform relaxation tests to calibrate creep/viscous behavior.
   - Run tests designed to separate visco-elastic and visco-plastic effects.
   - Conduct hysteretic loop tests under subcritical loading to capture cyclic response.
   - Acquire advanced experimental data for further model refinement.

4. **Model Refinement**
   - Refine both DM and MS using the advanced experimental data to improve their predictive capabilities.

5. **Validation**
   - Run validation tests under sustained and fatigue loading conditions.
   - Compare model predictions (e.g., fatigue creep curves, lifetime predictions) with validation test results.

6. **Iteration**
   - If further refinement is needed (e.g., discrepancies in validation), iterate the calibration and validation steps.
   - Otherwise, finalize the models and document the results.

## Key Features

- **Interleaved Approach:** Experimental and modeling activities are closely coupled, with each informing the other.
- **Scenario-Based Testing:** Specific loading scenarios (LS1, LS4, etc.) are used to target different aspects of material behavior.
- **Iterative Refinement:** The process supports multiple cycles of calibration and validation to achieve robust, validated models.
- **Model Diversity:** Both discrete and microplane models are developed and refined in parallel.

This workflow ensures that material models are rigorously calibrated and validated against a comprehensive set of experimental data, supporting reliable predictions for structural applications.
