Providing fast and accurate finite element analysis
Generating optimal design concepts using topology and topography
optimization
Providing traditional size and shape optimization to maximize the design
performance
The design process can be viewed as an optimization process to find structures,
mechanical systems, and structural parts that fulfill certain expectations towards their
economy, functionality, and appearance. Generally, the design process is an iterative
procedure consisting of the following components:
Conceptual design
Design
Testing
Optimization
Today's testing ground is usually the computer. Finite element analysis (FEA) and
Multibody Dynamics Analysis (MBD) are the most used tools for computational design
testing. The results of computational analyses are used to determine design
improvements.
Changes to the design are introduced in all phases of the process. At a certain stage of
this process, changes to the concept become prohibitive. The concept phase plays a
fundamental role concerning overall efficiency of the design and the cost of the overall
development process.
In the concept phase of a design process, the freedom of the designer is limited only by
the specifications of the design Figure 1. Today, the decision on how a new design should look is based
largely upon a benchmark design or on previous designs. The decision making is based on
the experience of those involved in the design process. Conceptual design tools such as
topology and topography optimization can be introduced to enhance the process. The
concept can be based on results of a computational optimization rather than on
estimations. Using topology and topography optimization, the initial design step is
already based on input generated using computational analysis. Topology and topography
optimization redefine the role of computational analysis and simulation in the design
process. Finite element analysis has matured from a testing tool to a design tool.
Figure 2 compares the design process using topology optimization with the
conventional method of leaving the concept entirely to experience and intuition. The
overall cost of design development can be reduced substantially by avoiding concept
changes introduced in the testing phase of the design. This is the major benefit of
modifying the design process by introducing topology and topography optimization.
In the real world, the design process is not as straightforward as described above. The
design is not just driven by one performance measure -- it has to be viewed as a
multidisciplinary task. Today, the different disciplines work more or less
independently. Analysis and optimization is performed for single phenomena such as
linear static behavior or noise, vibration and harshness. Still, the idea persists that
if one performance measure improves, the whole performance improves. A simple example
shows that this is not quite true. Take the design of a car -- a high stiffness is
necessary for good driving and handling, and high deformability is important for the
crashworthiness of the design. This shows that improving one measure may result in
degrading another. Therefore, compromises must go into the formulation of the
optimization problem. The definition of the design problem and of the design target is
most important. The solution can be left to computational means. Multidisciplinary
considerations, especially in the conceptual design, are, in many ways, still active
research topics and are being covered by future developments of topology optimization.
However, the inclusion of manufacturing constraints into topology and topography
optimization is already implemented in OptiStruct.
OptiStruct also provides size and shape optimization to
completely support the design process with finite element based structural optimization.
Using the advanced interfacing with HyperMesh, the
generation of input data for structural optimization becomes an easy task. This allows
structural optimization to be integrated into the design process seamlessly.