Research
The field of computational mechanics deals with the investigation and development of numerical, computer-oriented methods as well as the associated algorithms and calculation software for solving engineering problems whose physical behavior can be described by adequate mathematical models.
The integrated approach of theory, experiment and numerics on the one hand and the use of the possibilities of modern computer technology on the other have decisively shaped this field. The availability of increasingly powerful computer systems, from personal computers and workstations to supercomputers with vector and parallel processors, combined with advances in theory, measurement technology and experimental mechanics, has opened up new possibilities for the virtual design and simulation of complex and increasingly intelligent products, processes and procedures.
It is now possible to develop realistic computer models, even for very complex systems, with which the system behavior can be described with sufficient accuracy and analyzed under different operating conditions. This provides new insights and knowledge about system behaviour that can be used for further improvements and optimization. Virtual product development is becoming increasingly important for industry because development times can be reduced and costs saved.
- Explicit time integration: is a numerical method that can be used to solve dynamic processes in mechanical structures
- A mass matrix describes the mass distribution within an element using shape functions and is usually consistent (fully populated)
- Mass lumping refers to approaches that transform the consistent structure of the mass matrix into a diagonal structure, but with a reduction in achievable accuracy
- The combination of explicit time integration with a diagonal mass matrix allows for enormous savings in computational time
- The reduced accuracy can increase the number of time steps or the requirement of higher-order elements, which enlarges the format of the system matrices and thereby increases the computational time
- Objective: Formulate a new mass lumping approach that produces comparable or more accurate results for transient simulations compared to conventional mass lumping methods
- Development of a dynamic AFO using silicone/shape memory alloy (SMA), and elastic bands for improved flexibility and performance
- Addressing current limitations of polymer-based AFOs, such as low biomechanical properties and long-term skin irritation
- Providing a cost-effective alternative to advanced composite and carbon-fiber AFOs.
- Design and evaluation using digital tools like 3D scanning, CAD, Finite Element Analysis (FEA), Design of Experiments (DOE), and neural networks
- Prototype fabrication and testing to evaluate biomechanical effectiveness
- Material models: mechanical behavior of various materials regarding physical variables such as strain, strain rate or temperature
- Classical material models may not be able to capture the overall complexity of a material under certain circumstances without violating physical laws
- Physics-augmented neural networks have implemented physical constrains by construction resulting in physically reasonable results even outside the trainings range and a high flexibility
- The material models are implemented in (non-)commercial FEM codes
- Aim: improve prediction accuracy of simulations for highly-dynamic systems with rubber bushings
- Application: including laboratory centrifuge, electrically powered car
- Material model: extended, physically-motivated dynamic flocculation model (DFM), capable of modeling complex material behavior in 1D
- Implementation in FEA: DFM is generalized to 3D via the Concept of Representative Directions and implemented as UMAT
- Focus of this project: efficient coupling between multibody simulation and nonlinear FEA & extension of DFM
