To demonstrate the capability of this framework, three prescribed deformation profiles are targeted by three distinct optimization procedures. In all instances, the deformation profile is successfully targeted. To verify the accuracy of the optimized structures, high-fidelity single-scale simulations are performed. In each case, excellent agreement is noted between the high-fidelity simulations and the corresponding optimized macroscale displacement fields, with errors of less than 10%. In all instances, the deformation profile is successfully obtained through continuous optimization of the amplitude parameters. To verify the accuracy of the optimized macroscale displacement fields predicted by the multiscale structural analysis, high-fidelity simulations of the reconstructed geometries are performed.
- The need for multiscale modeling comes usually from the fact that theavailable macroscale models are not accurate enough, and themicroscale models are not efficient enough and/or offer too muchinformation.
- A more rigorous approach is to derive the constitutive relation frommicroscopic models, such as atomistic models, by taking thehydrodynamic limit.
- Importantly, a full-factorial DOE is selected for this application, as the uniform distribution of simulation nodes affords a number of advantages.
- This procedure is initiated by pre-populating the microscale parameter space with the simulation nodes of a full-factorial Design Of Experiments (DOE) (Antony 2023).
- In this case, locally,the microscopic state of the system is close to some local equilibriumstates parametrized by the local values of the conserved densities.
- 5, which depicts the macroscale strains that correspond to the minimum potential energy for each load step, superimposed on the resolved design space.
- In 2006, he was a Plenary Lecturer at the International Congress of Mathematicians in Madrid.
Prologue to Multiscale, Nonlinear and Adaptive Approximation II
Advances in additive manufacturing (AM) have enabled the fabrication of complex geometries previously inaccessible through traditional subtractive technologies (Attaran 2017; Prakash et al. 2018). This has prompted a revolution within the domain of structural design, as researchers seek to design frameworks capable of leveraging this new-founded design flexibility in the pursuit of enhanced structural performance (Plocher and Panesar 2019). In the heterogeneous multiscale method (E and Engquist, 2003), one startswith a preconceived form of the macroscale model with possible missingcomponents, and then estimate the needed data from the microscalemodel. Whilethe simulation and analysis technology for metal structures such as car framesis quite robust, the analysis of novel “advanced materials” is lagging. Theconsensus is that by using conventional techniques (standard FEA) it is notpossible to accurately simulate these materials without extensive experimentaland empirical “calibration” data.
Multiscale modeling of microstructure–property relations
In parallel, static network metrics, such as clustering coefficient, modularity, and static Kuramoto index reveal fixed structural properties, providing complementary characteristics into community cohesion and connectivity efficiency. This low-dimensional representation is then fed into a convolutional self-attention enhanced model, designed to capture both localized dependencies and long-term sequence dynamics through its hybrid architecture of convolutional layers and self-attention mechanisms. Achieving a 100% classification accuracy across stone sizes, this methodology highlights UMAP’s robust capability to retain complex, multi-scale structures, facilitating precise class differentiation. The benefits afforded by concurrently coupling the micro- and macroscale models are demonstrated by this case, as only 19, 654 parent microscale simulations are required to reach convergence of the optimization procedure. This number of parent microscale simulations represents only 0.31% of the total parent microscale database and only 0.079% of all possible permutations, despite both shear and direct strains exceeding 22%.
- Lighthill introduced a more general version in 1949.Later Krylov and Bogoliubov and Kevorkian and Cole introduced thetwo-scale expansion, which is now the more standard approach.
- Applying a 12-level Maximal Overlap Discrete Wavelet Transform for multiscale decomposition, each signal is segmented into transition graphs that quantify both transient and stable structural features.
- The transformed set of points is then inspected to determine how each parameter is permuted during the transformation procedure.
- The microscale model represents a data-driven continuous functional which relates geometric parameters and the local macroscale strain tensor to the local macroscale stress tensor for each element within the macroscale domain.
- Quantitative methods for maximising the information that can be retrieved from these images have not kept pace with technological developments, and no standard methodology has emerged for spatial data analysis.
- Thus, the introduction of new materials intoa structure results in increased time to market and costs.
- To demonstrate the capability of this framework, three prescribed deformation profiles are targeted by three distinct optimization procedures.
Multiscale Analysis: A General Overview and Its Applications in Material Design
Thus, the introduction of new materials intoa structure results in increased time to market and costs. The advent of parallel computing also contributed to the development of multiscale modeling. Since more degrees of freedom could be resolved by parallel computing environments, more accurate and precise algorithmic formulations could be admitted. This thought also drove the political leaders to encourage the simulation-based design concepts.
The different models usually focus on differentscales of resolution. They sometimes originate from physical laws ofdifferent nature, for example, one from continuum mechanics and onefrom molecular dynamics. In this case, one speaks of multi-physicsmodeling even though the terminology might not be fully accurate. Some of these techniques aim to homogenize the properties of the local scale; others attempt to capture nonlinear behavior via curve fitting and progressive damage approaches. Many of the most famous techniques, such as those evaluated in the World Wide Failure Exercises, are related to the analysis of unidirectional composites. The key is that the user must be very aware of the assumptions and bounds of their model when employing one of these techniques.
When the system varies on a macroscopic scale, theseconserved densities also vary, and their dynamics is described by aset of hydrodynamic equations (Spohn, 1991). In this case, locally,the microscopic state of the system is close to some local equilibriumstates parametrized by the local values of the conserved densities. The first type areproblems where some interesting events, such as chemical reactions,singularities or defects, are happening locally. In this situation,we need to use a microscale model to resolve the local behavior ofthese events, and we can use macroscale models elsewhere. The secondtype are problems for which some constitutive information is missingin the macroscale model, and coupling with the microscale model isrequired in order to supply this missing information.
Motivation for multiple-scale analysis
Therefore tryingto capture the macroscale behavior without any knowledge about themacroscale model is quite difficult. Of course, the usefulness of HMMdepends on how much prior knowledge one multi-scale analysis has about the macroscalemodel. In particular, guessing the wrong form of the macroscale modelis likely going to lead to wrong results using HMM. However, precomputing such functions is unfeasible due to thelarge number of degrees of freedom in the problem. The Car-Parrinellomolecular dynamics (Car and Parrinello, 1985), or CPMD, is a way of performingmolecular dynamics with inter-atomic forces evaluated on-the-fly usingelectronic structure models such as the ones from density functional theory.