August 2009 Contents
Application Brief: Designing for Cost Reduction
Application Brief: Optimizing Traffic Signal Control
Announcement: HEEDS Chosen as Editor's Pick
HEEDS Tip: Searching the Log Space of a Design Variable
Announcement: New HEEDS with Guides Available
Technical Papers: Recent Publications Featuring HEEDS
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Designing for Cost Reduction
Application Brief
We normally think of optimization in terms of reducing mass or increasing performance of a product, but often the underlying goal is to reduce product cost while achieving a target performance. Product cost may be a function of many factors such as material type, amount of material used, manufacturing process, number of parts, assembly details, and more.

The relationship between cost and design variables (e.g., shape, material, gauge thickness, location of features, etc.) is highly implicit. In other words, it is often difficult to understand the direct effect that changing one or more variables will have on cost. But mathematical design optimization has the ability to efficiently explore these complex relationships. For this reason, it is a powerful tool for achieving a cost effective product design.

In this application brief, we demonstrate how to couple a cost model and a finite element model within an optimization process to obtain a minimum cost design that also meets performance requirements.

The application example is an office chair leg with both material and shape design variables. HEEDS is used to automate the design evaluation and optimization process, Abaqus is used to perform finite element analysis, and Excel is used to calculate the cost of each proposed design.

Read the entire application brief
Optimizing Traffic Signal Control for Emergency Evacuation
Application Brief

Agent-Based Modeling (ABM) is an effective strategy for simulating the emergent properties of complex systems. This form of simulation models the behaviors of individual agents interacting with each other and with their world. ABM is well suited for problems such as modeling behaviors during emergencies, or critical incidents. These situations can range from getting people out of a burning building to routing traffic away from a chemical spill. 

While ABM works well for modeling individual behaviors to determine the resulting emergent group properties, it is difficult to find optimal strategies for emergency responders to follow in order to save lives, faced with such scenarios. Parameters must be tuned and tested to find optimal strategies for handling various kinds of incidents.

Furthermore, in order to test each possible strategy, one or more simulation runs may take a very long time. It becomes impractical to test the many combinations of parameters for possible strategies in an exhaustive manner, so a more efficient search method must be used. In this case, it is advantageous to use an optimization tool with evolutionary and hybrid computation, such as HEEDS Professional.

While most applications of HEEDS focus on design of physical parts and products, HEEDS can also be applied to many other forms of optimization. This paper discusses the success of HEEDS in the area of traffic control for urban evacuation, using agent-based modeling.

Read the entire application brief
HEEDS Selected as Desktop Engineering's Editor's Pick of the Week

In June, Desktop Engineering magazine chose HEEDS Professional 5.3 as the Editor's Pick of the Week.

"HEEDS Professional optimizes your design optimization workflow by harnessing numerical search algorithms," said Anthony J. Lockwood, editor at large for Desktop Engineering.

"The key to HEEDS is its SHERPA technology, a hybrid search algorithm that combines its own strategies with other known methods -- genetic algorithms, e.g. -- then leverages them all automatically and simultaneously to explore your design space and optimize the design. This phalanx of search algorithms brought to bear on a problem requires fewer iterations to converge on the optimal design because it eliminates the inefficiencies inherent in running one method over and over."

"You do not have to be an optimization technology maven to put SHERPA to use," added Lockwood, "You set up a design optimization through a simple process. What this all means for you is that HEEDS Professional increases your productivity, reduces wasted time and money, gets products to market faster, and frees up computer resources for additional productive work."

Read the complete Editor's Pick of the Week
Searching the Log Space of a Design Variable
HEEDS Professional Tip

In cases where a design variable ranges over several orders of magnitude, it often makes sense to define the variable range in log space instead of linear space.

Searching the log space allows you to find the value of the design variable that is within a certain percentage of the actual best value, as opposed to an absolute precision. Instances when it is appropriate to use this technique may include curve-fitting and determining chemical rate constants.

In this HEEDS tip, search of the log space is explained and instructions are given for how to set this up in HEEDS.

HEEDS with... Guides Available

Our customers frequently ask us for more information about how to use HEEDS Professional with their preferred design and analysis tools. In response to these requests, our support engineers are continually expanding the selection of HEEDS with guides. The following guides are currently available to our customers at no cost:

HEEDS Professional with
  • Abaqus
  • DEP Morpher
  • Excel
  • Fluent
  • HyperMesh/HyperMorph
  • Matlab
  • Moldflow
  • NX
  • Patran
  • SolidWorks
If you'd like to request a PDF of any of these guides, please
call us or send an email to support@redcedartech.com.
Recent Publications Featuring HEEDS
Technical Papers

HEEDS Professional was used in the following recently published optimization study:

Qualifying nonlinear anisotropic elastic material properties of biological tissue by use of membrane inflation
J. Bischoff, E. Drexler, A. Slifka and C. McCowan
Computer Methods in Biomechanics and Biomedical Engineering
Vol. 12, No. 3, June 2009, 353-369

Read the abstract

Browse more technical papers featuring HEEDS Professional

As always, we hope you have found this issue informative and interesting. If you have questions or feedback, please don't hesitate to contact us.
The Red Cedar Technology Team

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