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Create New Possibilities with Custom Material Models and C++ Subroutines



Create your own material model


One of the main challenges in Computer Aided Engineering (CAE) simulations is accurately representing the complex behavior of real-world materials. This accuracy is especially crucial in multiscale simulations, where the accurate response on a global scale depends on the detailed mechanical representation of each microconstituent and its interfaces. To meet the needs of designers working with parts that have complex microstructures or advanced new materials, the Simcenter Multimech 2306 enables users to create their own material models through user-defined subroutines in C or C++.


Engineers and researchers have traditionally faced difficulties related to the modeling of advanced materials. Standard material libraries often do not cover the full range of materials used in different industries and products, which often forces engineers to compromise their material models and accept some inaccuracy in the results. Furthermore, not all CAE tools support user-defined materials in multiscale simulations, where some or all microconstituents require custom materials.


Support for user-defined custom materials in Simcenter Multimech offers a powerful solution to these challenges. Custom materials can be applied in different types of simulations, whether in global scale part models, microstructural scale virtual tests or True Multiscale simulations.


First example: fatigue in adhesive joints


Adhesive materials have a different mechanical response when compared to common engineering materials such as metals. Furthermore, its response varies widely depending on factors such as composition, humidity and temperature. Simulating models containing this type of material is an excellent example of the effectiveness of Simcenter Multimech's custom subroutines. A specific case involves the cyclic loading of an adhesive joint with gradually increasing load. A custom constitutive relationship, specially developed to model the adhesive behavior under fatigue, was coded and applied to the adhesive elements. The results demonstrate how the subroutine captures the different fatigue responses in each condition, also identifying the areas most susceptible to fatigue failures.


Second example: custom fault model with gradual stiffness reduction


The example above shows a single-scale use of the new feature, as no microstructural features were modeled. That is, the complete model is in the scale of the components and the adhesive joint. However, user-defined subroutines can also be applied in multiscale analyses, to model the response of specific microconstituents. A powerful example of this new feature in a multiscale simulation is the creation of a user defined failure criterion. A common application for failure criteria in CAE simulations is to reproduce phenomena such as fracture, cracking or detachment, reducing the stiffness of elements to almost zero if a specific criterion is met. In this case, the path of the reduced stiffness elements represents the fracture path.


Although failure models exist in most CAE tools and have been used for decades, convergence is a common challenge: abrupt reduction in stiffness can lead to higher residuals, requiring careful mesh selection, time lag strategy, stabilization etc. , users can develop a failure model in which the stiffness is not immediately reduced, but gradually decreases over several time steps. The figure and animation below demonstrate how the gradual decrease in stiffness occurs:


The result of custom failure criteria in a real multiscale simulation is an improvement in the convergence of the nonlinear analysis, leading the simulation to progress much further than using a simplified failure model. Extended results allow users to perform post-failure investigations, showing how the component under investigation behaves after each localized failure mechanism has occurred.



Unlimited possibilities with your own material models


The examples shared above demonstrate just a fraction of the potential that can be unlocked by customizing material models in Simcenter Multimech. Other application examples include:

  • Temperature dependence and strain rate in metals

  • Custom multiaxial damage and fault models

  • Low-cycle fatigue on microstructural components

  • Mechanical response of unusual materials such as glass, sand, cardboard, wood, etc.

Furthermore, as far as multiscale simulations are concerned, material subroutines in Simcenter Multimech can be used at microstructural scale along with global scale models solved in Simcenter 3D in different solvers such as Nastran, Samcef, Abaqus or Ansys. This means that it is now possible to code material subroutines that work with any of these solvers in C++, instead of their native Fortran programming.


For users struggling to meet expectations due to material complexity and inaccuracies caused by incorrect material modeling, user-defined models in Simcenter Multimech are a tangible solution. Comprehensive guidance and examples of code, compilation, and usage are provided in the Simcenter Multimech documentation.


Opportunity: Increasingly, advanced computer simulations can be used to reduce costs and shorten the timeframes of R&D projects that were previously only based on physical experiments. Simcenter Multimech is an excellent example in this direction. With the use of intensive simulation in the conceptual stages of the development of new materials, we can be more assertive in the construction of performance proof experiments!


Simcenter Mechanical 2306


Simcenter Multimech is part of the Simcenter Mechanical group of Simcenter Simulation Software Solutions. This version of Simcenter Multimech was therefore part of the Simcenter Mechanical 2306 version, to learn more about Simcenter Click Here! Discover the power of customization in CAE simulations with CAEXPERTS! Book your exclusive meeting now and explore how to create your own advanced material templates. Click the button below to book your time slot right now!


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