In multi scale modeling, what are the deciding factors that dictates selection of particular scale of modeling ?
The type of model to use depends on the research question you are addressing and which (experimental) information you have about the structure, components and interfaces of the material. You need hypotheses for the governing physics of the material property you are investigating, and then make an as simple as possible model that captures these physics to test your hypotheses, and hopefully answer your research question.
Don't rush off to model "all" scales, as this may obscure your results in the end by introducing an overwhelmingly large number of unknown parameters. Try instead to judge what is the appropriate number of scales for your particular problem. For instance, it is not a given that you need to make a nanoscale model of the nanoparticles. Maybe you don't know so much about the structures they form or the interface they make with the matrix? Then it may be better to do an experimental/literature study on the nanoparticle/matrix material and model it as a continuum. Again, it depends on what you know and on what you want to predict.
Kindest regards,
/Stefan
Hierarchy of models (nano-mesa-macro) is used to solving the specially formulated problem at a lower level to determine:
- Effective values of the parameters of of the medium to solve the problem on a larger scale
or
- The parameters of the boundary conditions
for the problem at a higher level (an increase scale of space and / or time).
And the one goal - a multiscale model and the resulting solution based on it must adequately describe the physical processes. In this case the problems associated with the limited computational resources are overcome.
Have a look on multiscale modelling:
http://puccini.che.pitt.edu/~karlj/Classes/CHE3935/MD_simulations.pdf
The type of model to use depends on the research question you are addressing and which (experimental) information you have about the structure, components and interfaces of the material. You need hypotheses for the governing physics of the material property you are investigating, and then make an as simple as possible model that captures these physics to test your hypotheses, and hopefully answer your research question.
Don't rush off to model "all" scales, as this may obscure your results in the end by introducing an overwhelmingly large number of unknown parameters. Try instead to judge what is the appropriate number of scales for your particular problem. For instance, it is not a given that you need to make a nanoscale model of the nanoparticles. Maybe you don't know so much about the structures they form or the interface they make with the matrix? Then it may be better to do an experimental/literature study on the nanoparticle/matrix material and model it as a continuum. Again, it depends on what you know and on what you want to predict.
Kindest regards,
/Stefan
Composite structural analysis deals with evaluating performance of composite structures under given loading condition. Composites design deals with working out the configuration of the composite structure for the intended purpose. The input necessary for such exercises is the thermomechanical behavior of composite material at micro, meso and macro level.
Because of inherent nature of composite materials, composite structure at macro scale can be discretized into repetitive unit cells (RUCs). It is mainly true for textile composites. In an ideal situation, all the RUCs would be geometrically identical. But, boundary condition can be different based on the location of the RUC in the macro structure. In the absence of ideal fabrication process for the composite structure, different RUCs may have different geometrical configuration even though the difference could be marginal. Such RUCs are referred meso RUCs. Meso RUC consists of curved / straight impregnated strands / yarns, neat resin and interface.
Impregnated strand cross section consists of micro repetitive unit cells (RUCs). Possible damages at micro level are unequal distribution of fibers in strand cross section, undulation in filaments along length, debonding, fiber breakage, matrix micro cracking and yielding. Considering all such micro damages, there can be different micro RUCs. Analyzing micro RUCs considering all possible micro damages and obtaining homogenized mechanical behavior of impregnated strand is micro analysis.
Possible damages at meso level are damages in impregnated strand, debonding between impregnated strand and matrix, micro / macro cracks in matrix and possible geometrical non-uniformity. Boundary conditions for different meso RUCs can be different. Analyzing meso RUCs and obtaining mechanical behavior is referred maso analysis.
Starting with different meso RUCs and corresponding boundary conditions, homogenized mechanical behavior of composite structure (macro structure) is obtained. Such an analysis is referred macro analysis.
Stephan's advice is an excellent starting position.
The remaining 4 answers give other facets of the proposed study.
Best of luck
George H. Myer
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Composites