Multiscale Materials Modelling
At the heart of understanding material behavior lies the examination of phenomena occurring at diverse length and time scales. Historically, individual disciplines—ranging from quantum mechanics to continuum mechanics—have specialized in exploring specific scales, from atomic and molecular up to macroscopic levels.
Multiscale Materials Modelling endeavors to bridge these scales, employing a hierarchical approach to couple models from the finest atomic scales to broader macroscopic scales. At the atomic level, electronic structures dictate material properties, and understanding the positions of atoms and their underlying potentials is crucial. As we transition to larger scales, atomistic models are often too computationally expensive, necessitating the use of alternate representations which can capture the essence of the material behavior without delving into atomic detail.
This upscaling is a meticulous process, requiring the development of transition models that maintain the continuity of local physical variables, such as displacement or temperature. Such continuity ensures that the physics at one scale transition seamlessly into the next.
Additionally, a central challenge in multiscale modelling is uncertainty quantification. As we derive coarse-scale properties from finer-scale models, there's inherent uncertainty involved. Quantifying this uncertainty is pivotal, as the fidelity of the macroscopic model depends on the accuracy and reliability of its foundational microscopic models.
Modeling Microscale Defects in Aluminum: A Comprehensive Static and Dynamic Approach
Objective: The core aim of our research endeavor is to devise an in-depth model tailored for the understanding and representation of microscale defects inherent in aluminum structures. By skillfully integrating both static and dynamic coupling techniques, we set out to create a tool of unmatched efficiency and accuracy.
Methodology: To address the challenges posed by sub-micron scale defects, we employed the quasicontinuum method. This method permitted an intricate representation and analysis of the region immediately surrounding the defect. For areas farther away from these defects, the time-tested principles of continuum mechanics were invoked to provide an encompassing perspective on the material behavior.
Further detailing our methodology:
Static Coupling: Our model leverages a straightforward iterative method tailored for static loading scenarios. With its rapid convergence, often within O(1) iterations, this technique forms the backbone of our coupling research for static problems.
Dynamic Coupling: Transitioning to dynamic loading scenarios, our methodology embraces a coupling for dynamical challenges, addressed in both time and frequency domains. The Spectral Finite Element Method is integrated into this, accentuating the speed and precision of our analysis.
Key Findings:
Holistic Analysis: The amalgamation of static and dynamic coupling methods offers a model that masterfully captures the intricate behavior of aluminum systems with microscale defects.
Static Coupling Efficiency & Robustness: The iterative mechanism in static coupling not only showcases rapid convergence but is also robust against variations in multiple parameters, guaranteeing trustworthy outcomes in static conditions.
Dynamic Coupling Precision & Speed: While the preparatory offline work is extensive for dynamic coupling, the method excels in speed and accuracy. The integration of the Spectral Finite Element Method augments its effectiveness, ensuring a thorough and precise assessment of dynamic situations.
Implications:
Advanced Computational Tools: Our model serves as a blueprint for the development of advanced computational tools and methodologies, potentially guiding research in other metals and materials.
Safety and Reliability: The ability to predict and understand the behavior of these defects allows industries to manufacture safer and more reliable products, particularly in sectors like aerospace where the integrity of materials is paramount.
Cost-Efficiency: By leveraging our model to predict defect behavior and its implications, industries can potentially reduce wastage and rework, leading to significant cost savings in the long run.
Informed Decision-making in Manufacturing: With a clearer understanding of the intricacies of aluminum behavior, manufacturers can make more informed decisions regarding processes, quality control, and defect mitigation.
Deep Material Network: An Innovative Approach to Composite RVE Representation
Objective: The primary aim of our research was to comprehensively study the Deep Material Network technique—a pioneering approach that synergizes principles from physics and machine learning to efficiently characterize a composite Representative Volume Element (RVE).
Methodology: Utilizing the foundational concepts of the Deep Material Network, we embarked on an exploration to discern its capabilities. In particular, our focus was on its adeptness at capturing the morphology of composite materials. During the course of our investigation, we introduced modifications to its standard implementation.
Progress:
Efficiency in Capturing Morphology: The Deep Material Network showcased proficiency in representing composite morphology, which further enabled us to determine the composite's response even under previously unseen loading conditions.
Enhanced Training Speed: Post our alterations, the training speed exhibited a marked improvement, registering speeds that were three times faster than what was reported in prior publications.
Rapid Stress-Strain Response Determination: One of the standout achievements of our research was the ability to swiftly gauge the stress-strain mechanical response. This process was executed approximately 100 times faster than conventional Finite Element (FE) methods.
Accuracy of the Surrogate Model: Despite the time-efficiency of the Deep Material Network, its accuracy remained uncompromised. The model's results were consistently within a 2% margin of traditional FE results, all achieved in a fraction of the time.
Implications: The implications of our research are profound, particularly for sectors reliant on composite material analysis. With the ability to provide accurate results in significantly reduced timeframes, the enhanced Deep Material Network can revolutionize efficiency metrics in composite RVE analysis and potentially pave the way for further advancements in the integration of physics and machine learning.
Selected Publications:
Anay Mohan Shembekar, S. Gopalakrishnan, Atomistic and continuum length scale coupling in materials using quasicontinuum method, Materials Today: Proceedings (2023) Link to article