The simultaneous solution of both global and local problems (with two-way coupling) is considerably advantageous in cases where the microstructure changes and/or its behavior is history dependent. These changes can be physical, such as crack localization and/or viscoelasticity, or chemical, such as oxidation. In most practical problems, there exists a sustainable amount of damage induced by the formation and growth of micro-cracks. In this case, multiscale modeling can be particularly effective, since the evolution of the microstructure is necessarily both spatially and time dependent.
Why use multiscale modeling?
The need for economically feasible and efficient applications has increased significantly the complexity of engineering structures. As the complexity of applications increase, more complex materials need to be designed, as most materials found in nature do not have the desired features. For example, in the aerospace industry, high-strength and low-weight fiber-reinforced composites are used to minimize fuel consumption and still satisfy the minimum structural design criteria. In military applications, highly dissipative viscoelastic polymers are combined with high-strength fibers in order to produce materials that can be used in protective devices, such as tank armor and soldier helmets.
The idea is to combine different materials with different properties and produce a third material that meets the design requirements, and which is inherently heterogeneous. From the engineering point of view, heterogeneous materials are desirable because they can be suitably designed to take advantage of particular properties of each constituent. For example, carbon fiber-reinforced composites have wide applicability due to their superior thermo-mechanical performance and low weight, obtained due to the fibers, and their versatility in shape (parts of any shape can be molded) due to the use of epoxy matrix.
Since the overall behavior of heterogeneous materials is strongly affected by the mechanical properties of the individual constituents as well as by geometrical characteristics, such as volume fraction, shape, size, spatial orientation and distribution of particles/fibers, MultiMech™, a unique two-way coupled multiscale computational software, is a natural choice of tool to perform effective and accurate analysis and design of such advanced materials. The term two-way coupled is used to denote that, in MultiMech™‘s approach, both global and local scale problems concurrently exchange information with each other, thus providing the most advanced solution available in market.
Besides, MultiMech™ is fully parallelized and the user can take advantage of multi-core (cluster) infrastructures in order to accelerate results, as shown in the Figure below for a particular multiscale benchmark problem.