AG Modeling, Simulation, Optimization
Speaker: Dr. Helmut Guth
Tasks and Objectives of the Working Group on Modeling, Simulation, Optimization
When designing complex technical/physical systems, prototype construction usually is associated with a significant expenditure in terms of materials and time. As an alternative, it is considered to first develop models of the system, which describe this system by its underlying laws (e.g. in the form of mathematical equations). These models then serve as a basis of manual comparison of variants or - in a more advanced stage - of optimization using appropriate methods.
A completely different motivation for the use of modeling and simulation is observed in medical applications due to the irreversibility of surgical interventions. In suitable fields of use, modeling and simulation may be applied to better estimate the effects of an operation in a provident manner.
Applications are conceived under the HGF Programs of Health and Microsystem Technologies (MIKRO) at Forschungszentrum Karlsruhe. Activities focus on system design using the methods and tools of FEM simulation, optics simulation, simulation of network/behavior models (macromodeling), and their optimization.
Research Topics and Competencies
The finite element method (FEM) is a numerical calculation method to solve various physical field problems. The behavior of continua is described by partial, locally and temporally dependent differential equations.
Problems of structural dynamics, flow mechanics, electromagnetics, and heat transfer can be studied. Furthermore, several coupled field problems, such as thermoelastic or piezoelectric interactions, can be analyzed.
The FE method also allows for a close-to-physics treatment of problems. It is applied in different fields (micropump, medical test strips, actuator plates, virtual eye).
In the field of optics simulation, both microscopic and macroscopic problems are analyzed. Particular attention is paid to the simulation of free-beam optics and guided optics problems. Both components and complete optical systems are modeled and simulated.
As simulation methods, wave theory approaches as well as radiation theory descriptions are available. This allows for a wide range of optics simulation, from path-dependent design problems to coherently optical systems.
Optical components and systems are simulated for various applications (heterodyne receiver, distance sensor, infrared gas sensor, virtual eye).
Technical systems or partial systems are characterized by effects of various physical domains (e.g. mechanics, fluid dynamics, thermodynamics) which may interact. When modeling on the physical level (FEM models), interactions often cannot be considered adequately or very large models result, which are associated with unreasonably high computation times.
In case system behavior is described on the basis of energy flow laws, macromodels and behavior models can be applied to describe physical behavior on a more abstract level in a domain-overlapping manner using conventional differential equations. These models have shorter computation times and, hence, may also be used for design optimization.
Such models have been applied, for instance, to optimize the behavior of a micropump.
The design of complex technical systems requires modeling, simulation, and optimization. The concept of model-based optimization is aimed at obtaining a design of high quality with minimum prototype construction. For this purpose, various optimization methods (evolutionary and traditional numerical) are applied, which complement each other. This results in a partly considerable reduction of the necessary quality calculations in the form of simulations runs.
The evolutionary method and its hybrid were tested in optimizing a micropump, a heterodyne receiver, and an actuator plate.
Concrete Fields of Application
Applications are developed in cooperation with industry and other research institutions - partly within the framework of BMBF-funded joint projects (DEMIS, OMID).
Concrete projects pursued by our working group include:
Model-based system optimization of the micropump with GLEAM. Quality of the system model of the micropump is improved by using the FE method.
Simulation of the flow behavior of a capillarily driven fluid in a structured microchannel.
Use of the FE method for the simulation of the structural mechanics behavior of an actuator plate and for model-based topology optimization with GLEAM/HyGLEAM.
Use of optics simulation in the design of a coherently optical receiver. It was focused on design optimization with regard to tolerance stability.
Use of optics simulation in the design of microoptical distance sensors for precise distance measurement (work distances: 10 mm or 20 mm with working ranges of 1 mm or 10 mm). Here, it is focused on the linearization of spot movement on the detector element.
Model-based design optimization of an optical gas sensor with regard to tolerance stability
System for the pre-operative simulation of the behavior of the human eye following refractively surgical interventions.
We are interested in cooperating in particular with industry (SMEs). If you need support in the design of complex systems by modeling, simulation, and optimization, we shall be pleased to make available our expertise as well as our extensive tool environment.
The technological know-how developed by this working group comprises:
Comprehensive tool for simulating mechanical, thermal, electrical properties.
Tools for optics simulation.
Fully integrated environment for technical computation..
Independent evolutionary algorithm combining elements of evolution strategy and genetic algorithms.
A hybrid of deterministic local search methods and the globally searching GLEAM.
Simulation tools in the fields of fluid dynamics
Tool developed by our working group for the automatic execution of variant simulation in a computer network.
Links to Other Websites:
|Concrete Applications / Fields of Application related to this method group|
|Optimization and Resource Management in Grid Computing|
|Energy Systems Analysis|