Many companies that develop new composite materials are surprised when their product does not perform as expected during the physical testing and certification process. In addition to the many years wasted on developing the material, companies often spend more than $50M on developing and testing a single new material concept.
Why is it so difficult to predict part behavior? Part failure often originates at the microscale, however, many simulation tools are not capable of linking microscale failure to the macro scale. In order to accurately predict how a part will behave, true multiscale simulation is required in order to determine how behavior at the microstructure will impact the global part.
What are the advantages of performing multiscale FEA?
- Higher accuracy. Performing multiscale analysis allows engineers to input different constituent material properties and get a more realistic prediction of how the composite material will behave. This is because multiscale takes into account damage at the microstructure, which is often where failure initiates, including debonding, fiber rupture, and matrix failure. Simulating the constituent materials at the microscale gives a much more realistic result of how the composite material and part will respond under structural loads and, more importantly, predicting when part failure will occur.
- Predict how composites will fail. Multiscale analysis allows engineers who are performing structural analysis to observe the failure mode within a composite part, which in turn allows them to make design changes to mitigate that failure. For example, in continuous fiber composites, multiscale analysis can ensure that the material is optimally loaded, which is in the direction of the fibers. If a material is failing due to debonding then engineers can iterate the layup orientations to make the structure more conducive to the applied loadings. This ability to see where failure modes are occurring allows engineers to optimize part design for many different families of composites.
- Run a virtual design of experiments. Multiscale analysis can be used to distribute different types of micromechanics throughout a material model. Finite elements can reflect the true nature of materials: elements can be inconsistent, containing flaws such as resin pockets, weakened interfaces, or misaligned inclusions, all of which will reduce the strength of a composite. Multiscale technology allows engineers to customize a wide variety of non-ideal microstructures that represent the more realistic nature of the composite. Because multiscaling can randomly distribute these defects and flaws throughout the part, a simulation can be run with the same number of flaws with the same geometry and mesh, but produce different results by changing the random distribution pattern. This will produce a variety of results, very similar to physically manufacturing these parts and testing them in a lab. This range of results is much more reliable and cost-effective because it allows engineers to gauge the variability in a certain part given the type of defect inserted within it.
While many simulation tools claim to be multiscale, MultiMechanics offers the only TRUE multiscale analysis, meaning it solves for both the global and the local scale simultaneously. Once a microstructure starts to develop damage, the stiffness of its elements will decrease, causing stress concentrations within the adjacent elements. This is a much more realistic representation of how a material will fail and can only be performed using MultiMech.
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