EAGLE Eliminates Tedious Tasks for Engineers

When engineers design a part or product, it is rare that their first design is the final product. With each design attempt, engineers test how a part or product will respond to real-world conditions and then alter its design. After many iterations, the engineer finally produces the optimal design.

Algor’s Engineering Application Generator, Language and Environment (EAGLE) is software which enables engineers to automate the process of creating the optimal design of a part or product. EAGLE is a programming language which enables an engineer to translate experience and knowledge as instructions which EAGLE follows to create the optimal design.

"Engineering a part or product is a process of trial and error," said David Dearth, engineer at Applied Analysis & Technology in Huntington Beach, CA. "With EAGLE, I give the parameters of the design, such as shape and maximum allowable stress levels, and tell the computer what steps to take, based on the outcome of the analysis. There’s no need for me to sit by my computer all day waiting for continuous, multiple analyses to run, just to make simple adjustments."

In one instance, Mr. Dearth used EAGLE to help him reduce the weight of three key components of an air refueling drive mechanism. This mechanism controls how the fueling hose from an air refueling tanker aircraft connects to other aircraft during flight. He used Algor to locate places in the components where weight could be removed without sacrificing the strength of the parts.

Using EAGLE for Design Optimization

At the beginning of the process for each part, Mr. Dearth used EAGLE to create a finite element model of the design, using large plate-shell elements. Generally, the more elements in a model the longer it takes the computer to run the analysis and the more accurate the results. Mr. Dearth selected a plate/shell approach for the initial model to simplify the EAGLE program instructions and optimization process. For the simplified plate/shell models, Mr. Dearth was concerned with addressing only essential structural details directly related to weight optimization. For these design cases, Mr. Dearth determined that the ability to run multiple analyses in a smaller amount of time was worth a small decline in accuracy.

After creating the initial model, Mr. Dearth ran a stress analysis to determine the strength of the component. The contracting company, Able Corporation, targeted the component’s weight reductions to be at least 30 percent and specified the areas where material should be reduced or removed.

Next, Mr. Dearth wrote an EAGLE program to run a series of redesign and analysis phases to find the optimal design of the component that would weigh less but still be strong enough to withstand the stresses it would encounter during operation. The EAGLE program he created began taking away material from specified regions of the component.

With each redesign and computer simulated testing phase, the radial size of the material that Mr. Dearth told EAGLE to remove increased if the analysis of the component showed that the stress was far below the designated levels. EAGLE continued to perform these tests without any human intervention until an analysis showed that the part would be subjected to too much stress.

"It wasn’t necessary to tell the computer to go back to a point that was between the last two iterations to do some fine tuning," said Mr. Dearth. "The analyses indicated that the 30 percent reduction in weight was easily met. In fact, we achieved an average reduction in weight of 50 percent for the regions which were targeted for weight optimization."

Following the final EAGLE-controlled analysis using the simplified plate/shell approach, Mr. Dearth performed another analysis of a solid model using smaller 8-node, 3-D "brick" elements. In the "brick" model, Mr. Dearth incorporated the structural details not deemed necessary for the initial plate/shell weight optimization EAGLE models.

With a solid brick model, Mr. Dearth could obtain the most accurate analysis to serve as final verification of the previous analyses using the simplified plate/shell elements. The analysis revealed that the weight savings suggested by EAGLE were correct and that the component, with the weight reduction, would be strong enough to function under real-world conditions. Mr. Dearth repeated the entire process for all of the components.

"Another benefit of using EAGLE in this instance was that with each of these components, the stress levels and materials were similar. So, there was even less work for me to do when defining the parameters since many of them were the same, thus saving me even more time," said Mr. Dearth.