Translation. Region: Russian Federation –
Source: Novosibirsk State University –
An important disclaimer is at the bottom of this article.
Scientists at the National Technology Initiative (NTI) Competence Center for Modeling and Development of New Functional Materials with Predetermined Properties (CNFM) at NSU have developed a Nonlinear Modeling Tool for Composite Materials. A mockup of the tool and prototypes of its individual modules are currently being tested.
The new software will enable engineers to build highly accurate models that account for nonlinear material behaviors such as viscoelasticity, elastic-plasticity, damage accumulation, and induced anisotropy. The computer models generated by the Designer will enable more efficient use of the strength reserves of functional materials. The development will find application in the aircraft and engine manufacturing industries, the oil industry, and medicine. The Designer was developed with financial support from the NTI Foundation.
"When computer modeling the deformation and failure of a complex component or mechanism, it's not enough to simply create a geometric model. It's also necessary to 'explain' to the computer program the materials used to construct the structure being modeled and the properties of these materials. For a long time, engineers calculated processes using simple linear models, as nonlinear models are a much more complex, yet more modern, approach. Importantly, nonlinear models are significantly more accurate than linear ones. They allow for more efficient use of the material's strength reserves, thereby reducing the cost and weight of the product and increasing its competitiveness," said Alexey Shutov, Doctor of Physical and Mathematical Sciences (Dr. habil.), a leading researcher at the NSU Center for New Functional Materials, regarding the relevance of this development.
An example of a linear model is Hooke's law, which everyone knows from school. Hooke's law states that the deformation occurring in an elastic body is directly proportional to the load applied to it. In other words, the harder we pull a spring, the more it elongates. The problem is that highly loaded materials behave nonlinearly: they can plasticize, creep, harden, or, conversely, accumulate damage; materials seem to remember what happened to them in the past. These are more complex effects that are poorly covered in standard engineering courses and that cannot be described within the framework of linear models. However, full-fledged nonlinear strength calculations are the prerogative of scientists studying solid mechanics—an interdisciplinary field at the intersection of materials science, mechanics, and computational methods.
"The idea behind our software is to make these competencies accessible to engineers so that the processes and technological steps required to build, configure, and implement a nonlinear model are automated. First, our Designer creates a nonlinear model signature—its fundamental description. Next, the Designer allows for the integration of experimental data, which is used to configure the model and test its predictive ability. After calibration, a computational algorithm is generated that implements the model in C. The resulting algorithm, in turn, is integrated into computational systems used to analyze the strength of products at the executable code level. Such systems include Ansys, MSC.Marc, Abaqus, and Logos," Alexey Shutov explained the development concept.
The model builder developed at NSU also addresses educational challenges, raising the level of competencies and culture in the field of nonlinear modeling.
"Our Designer includes an interactive model reference. The user can specify the task parameters, and the interactive reference will suggest which class of models to use to solve a specific problem, what experimental data is needed for calibration, and what the engineer can expect when applying such a model," added Alexey Shutov.
In construction and mechanical engineering, there are acceptable safety factors incorporated into structural design. A large safety factor is the price paid for ignoring the factors that influence a structure's performance. Nonlinear models generated by the Designer allow for more accurate calculations, and as a result, products can be designed with smaller safety factors. This is especially important for the aerospace industry, where structural weight is a key consideration.
The development of more accurate nonlinear models is also relevant for aircraft engine manufacturers (designing turbine blades and other highly loaded components), since in a competitive environment, the main focus is on reducing weight while simultaneously increasing efficiency, reliability, and engine power.
"Engineers have little experience working with modern, advanced materials, and they often lack sufficient experimental data. Gaining such experience through physical testing and experiments is an expensive and time-consuming process. For example, to implement a silicon carbide-based composite, it's necessary to understand how it will behave at a given temperature under a wide variety of loading scenarios, its service life, and how quickly it will degrade when a nick or crack appears. Solving these problems requires computer modeling and digital twins, which means high-precision nonlinear models are also needed," explained Alexey Shutov.
The designer developed at NSU can be used not only to simulate processes that will occur with existing materials but also to design new ones. For this purpose, the designer has a submodule—so-called surrogate models of representative volumetric elements. Essentially, it allows for the construction of complete digital twins that explicitly account for the microstructure of a composite material. Representative volumetric elements make it possible to predict the mechanical properties of new materials that have not yet been developed and tested based on the properties of individual phases, while surrogate models speed up calculations by hundreds of thousands of times.
"We also see great potential in the field of biomechanics. For example, Pavel Petrovich Loktionov's group is actively developing blood vessel prostheses at the Institute of Chemical Biology and Fundamental Medicine of the Siberian Branch of the Russian Academy of Sciences. From a mechanical standpoint, these are high-tech products made from functionally graded materials. It's important to calculate the mechanical properties of a prosthesis: on the one hand, it shouldn't be too rigid, otherwise there will be problems with implantation, and on the other, the prosthesis can't be too flexible, otherwise it will lose stability and cause an aneurysm. Therefore, it's necessary to select the optimal properties of the prosthesis, for which a mathematical model of the composite material from which the prosthesis is made is useful. Our Designer was created with an eye toward solving such important applied problems," added Alexey Shutov.
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