CAE vendors want--YOU: The every-day design engineer.
No longer are CAE software developers focusing strictly on the high-end expert or analyst. Features such as windows-based interfaces, PC hardware requirements, shorter learning curves, behind the scenes number crunching--and of course, less expensive software--all indicate these vendors are targeting the design engineer rather than the specialist.
Here's a look at five different companies who are doing just that:
A FOCUS ON THE MESH
Product: InCAD DesignPak
Company: ALGOR Inc.
"There is a perceived need for engineers to perform quick analysis checks on their models early on in the design cycle," says Michael Bussler, president of CAE developer ALGOR Inc. To address this need, the makers of Accupak Mechanical Event Simulation recently released InCAD DesignPak.
An engineer with zero analysis experience could easily run an analysis on his or her design without leaving a native CAD package, says Bussler. InCAD DesignPak allows users of mid-range CAD programs such as Solid Edge, SolidWorks, Pro/ENGINEER, and Mechanical Desktop to work with FEA meshes without file translations.
If ALGOR and the CAD system reside on separate computers, Direct Memory Image Transfer (DMIT) is used for seamless interoperability without file translation. "Competitors give different model translators for different CAD systems," says Bussler. "We cloned the program for all the CAD packages so a user isn't married to any one product."
Engineers developed InCAD DesignPak based on ALGOR's higher-end products. Because of this, InCAD DesignPak is completely compatible and scalable with the company's other software packages. Once modeled, the design can be pulled into any other ALGOR product without the need for translation or additional work by the end user. Also, a user familiar InCAD DesignPak could easily migrate to other company products with no learning curve because the interfaces are identical.
The software focuses on mesh quality rather than mesh size, says Bussler. "We begin with a solid surface mesh and build inward." The package also supports multiple element types.
For a bit more, $3,700, ALGOR offers InCADPlus. This package offers engineers, among many other features, the ability to perform surface and solid finite element analysis (FEA) modeling using ALGOR's Superdraw.
Coastal Systems Station, Naval Surface Warfare Systems Center in Panama City, Florida, supports the U.S. Navy in the area of Littoral warfare, which includes mine, amphibious and special warfare, underwater systems, and diving and salvage equipment. Recently, engineers at Coastal Systems Station designed a valve body in Solid Edge and then captured the geometry with ALGOR's InCADPlus and performed finite element analysis with ALGOR software to ensure that it could withstand high pressures. Engineers designed the valve to control the flow of gases such as helium, nitrogen, and oxygen into the breathing loop of a deep sea diving rig that goes beyond the limit of conventional scuba gear.
For diving beyond traditional depths of self-contained underwater breathing apparatus, a mixture of inert gases including helium and oxygen is used to prevent potentially deadly conditions such as oxygen poisoning, high-pressure nervous syndrome, and nitrogen narcosis. The 7,500-psi valve connects two spherical 5,000-psi Inconel flasks to a manifold that recirculates the gases. These components need to withstand high pressures because the breathing system must contain a large amount of gas in a compact area to provide sufficient life support for the duration required.
Engineers chose K-Monel material for the valve because it withstands pressure, is self-extinguishing to avoid the possibility of oxygen fires, resists the corrosive effects of seawater, and enables removal of the adjacent bottle without galling the threads.
After removing a threaded area from the model in Solid Edge, Coastal Systems Station engineers captured the geometry of the valve with ALGOR's InCADPlus, creating a very fine surface mesh. The surface mesh was subsequently refined using ALGOR's Merlin Meshing Technology to reduce the number of elements in non-critical areas. The model was then automatically meshed in ALGOR using the hybrid mesh option that combines bricks on the surface and tetrahedra inside. The result was a model with approximately 40,000 elements, with the majority of the elements on the surface, where accuracy is most critical.
A 7,500-psi loading was applied to the inner surfaces and force loadings were applied at each end to simulate the "pull" that adjacent components exert on the valve. The model was restrained on one side at the extension nub where the valve attaches to the high-pressure gas supply cylinder. This linear static stress analysis simulated the basic internal pressure load and end attachment loads. Coastal Systems Station engineers later analyzed the model with additional loads replicating worst case forces that could be induced onto the assembly during usage in order to produce a conservative design.
Prototypes not only withstood laboratory hydrostatic tests without any evidence of plastic deformation, but are currently being tested in prototype diving equipment. The computer-aided design and analysis work of Coastal Systems Station engineers ensured that only one set of prototype parts was required prior to manufacturing.
OBJECTIVE IS SIMPLICITY
Price: Starting at $4,000
Michael Giles has some unusual design specs. His equipment must withstand pressures of 30,000 psi, weigh 2,000 tons, and extend more than 2 miles into the ocean. As an engineer for Stewart & Stevenson Services Inc. (Houston, TX), Giles designs equipment for offshore oil drilling.
While this equipment is standard in offshore rigs that drill underwater wells, "working at these depths and pressures, every undersea well has a set of unique challenges," he says. Any engineering design or modification has to be analyzed.
Giles and fellow engineer Brian Sneed use DesignSpace™ design verification and optimization software, Versions 4.1.1 and 5.0. With DesignSpace, analyses can be performed directly inside a mechanical CAD package, in this case, Pro/ENGINEER from Parametric Technology Corp. (Waltham, MA). This eliminates the hassles and potential for error that come with moving geometry back and forth between the CAD and CAE. "There is no importing and exporting," Giles says. "The DesignSpace pull-down menu is at the right-hand end of Pro/E's toolbar. To use DesignSpace like this is simplicity itself."
The well shaft, or riser, extends two miles or more down to the seabed. The dead weight of this steel, in the water, by itself is enough to cause the riser to pull apart, especially in the stresses of a storm. DesignSpace lets Giles and Sneed rotate their models and slice them in half to see where the highest stresses are. "This is a great design help," Giles said. "And the ANSYS calculations reassured us that we can sometimes exceed ratings considerably, for example, a 103,000 psi load on something rated for 75,000 psi--provided that the loading is brief, infrequent, and isolated from most of the rest of the structure."
Kicks or explosions from 2 million-year old bubbles under incredibly high pressure disturbed by the drilling are absorbed by the blowout preventer (BOP). In this case the BOP has a 43-inch diameter piston and dome and sits on top of the diverter, which sits on top of the riser. Operating as a manifold, the diverter channels the gas, oil, seawater, and drilling mud coming up the riser into holding tanks and processing machinery. When there is a kick, the BOP's piston lets off the initial pressure jolt and then clamps the well shut.
"The BOP piston was designed so it could take indirect shear forces and even a little bending, a combination of required clearances and tolerances and a 50% safety factor," Giles reported. "Working with DesignSpace we tested and analyzed the constrained cylindrical forces on the upper part of the piston to pinpoint the high-stress areas," Giles said. "We had to be sure that when kicks hit, we would be able to avoid the bending. To simplify the analysis, we used DesignSpace to isolate the cylinder from the parts of the piston that were not going to be impacted."
This whole analysis was very easy to set up with DesignSpace 4.1.1, he continues, "And even easier with DesignSpace 5.0. The new version allows our models to account for different parts, different materials, and even different meshes. Without these capabilities, the solution could have taken 100 to 120 hours rather than two." The engineers finished their modeling and analysis on a custom-built PC with dual Intel. Pentium 300-MHz class CPUs and Windows NT.
Giles says that, "DesignSpace is for the R&D and production guy. Full ANSYS is for the analyst. The key to DesignSpace is that the design engineer can use it as he goes along, just drag and drop. The savings is that we don't have to stop, create another geometry file, e-mail it to the analyst, and then wait while he or she comes up with the answers."
NOT INTUITIVE, BUT STILL EASY
(Enterprise Software Products group)
Recently acquired by SDRC (Milford, OH) in September 1999, FEMAP is a Windows-native, geometry-neutral, finite element modeling software tool with more than 9,000 commercial CAE users worldwide. Organizations such as The Boeing Company, Lockheed Martin, NASA, and Mitsubishi rely on FEMAP to integrate multiple analysis technologies in a single modeling and visualization environment.
Many engineers, such as Randy Wise, senior designer for Ridgid tool manufacturer, The Ridge Tool Co. (Elyria, OH), use it everyday as their primary FEA program. Wise has used FEMAP on every project he's designed for the past four years, such as analyzing shear loads on beveled gears or performing drop test simulations on drill motor housings for hand tools.
Most recently, Wise used FEMAP to create a carriage handle for a threading machine from a piece of bar stock. "We turned a 17-piece component into a one piece design to reduce the cost of manufacturing and assembly," he says.
After designing the part in Solid Edge from Unigraphic Solutions (St. Louis, MO), Wise clicks on the FEMAP icon within the CAD program and the FEA software performs a default mesh by calculating the outside periphery of the model. When finished, FEMAP asks for a material. In this case, Wise wants to cast the piece in ductile iron. FEMAP finishes the mesh with mid-size nodes, as dictated by Wise. The whole process takes about 20 seconds. Wise works on a fairly fast machine, however: an Integraph TDZ 2000 with a 550-MHz processor and 256 Mbytes RAM.
While the program is not intuitive, it isn't too complicated to learn. "It took me about a week or two to become proficient with the software," says Wise. And once you've done a few projects, it gets easier. But if you don't use it for a couple of weeks, it takes a little while to pick it back up.
Because FEMAP is embedded into the CAD package, the two programs run concurrently. Checks can be run during the design and changes are easily implemented. If one determines that a part won't handle the stress, then he simply clicks back into Solid Edge, modifies the cross section, then proceeds with prototypes.
"I went to other higher-level FEA seminars," says Wise, "but decided that we didn't' need that much of a program, especially for the price." FEMAP is perfect for Ridge Tool's needs.
AN EYE ON ASSEMBLIES
Product: Working Model FEA
Sierra Pacific Engineering and Products (SPEP) designs and manufactures hinges, locks, bolts, handles, latches, and pulls made from steel, injection-molded plastic, aluminum, and die-cast zinc. When a client approached the company with a die-cast hinge to be redesigned for plastic for weathering characteristics and lower cost, SPEP decided it was time to invest in FEA software.
Requirements: the plastic part had to be as strong as the die-cast one and it would feature a rib configuration on the underside of the hinge to provide that strength.
To meet these specifications, SPEP evaluated three mechanical simulation software packages. "When we compared the other solutions to Working Model FEA we found a big difference," says Donald Rivadeneyra, a designer at SPEP. "I found the other programs difficult to use, and the results didn't look very good graphically."
Rivadeneyra begins a design using Mechanical Desktop® from Autodesk, Inc. and uses Working Model FEA for checking for interference, generating different configurations, and narrowing design alternatives. "We created five different rib configurations for the underside of the part," he says. "By analyzing each part in Working Model FEA, we quickly determined which was the strongest."
In the past, according to George Alvarado, SPEP's engineering supervisor, the company would have machined each prototype or invested in a prototype mold. "If we created five different rib configurations, it would have cost $5,000, required two weeks to machine, and up to two weeks to test. Now, we have a finished design in one to two days. Our costs are reduced dramatically."
Since then, SPEP designers and engineers have used Working Model FEA for a multitude of projects and varied engineering challenges. One design for the boat industry involved the creation of a custom flush-mount latch. "The latch was designed to withstand 50 lbs of stress," Alvarado says. "But by optimizing the design with Working Model FEA software we created a latch that handles 70 to 80 lbs. It's performing way beyond our expectations."
Working Model FEA also helped SPEP narrow down the best material for the injection-molded latch. Because the trailer would be used outside, the hardware had to weather everything from UV exposure to extreme temperatures, and heavy loads. With those potential wear problems in mind, Rivadeneyra contacted DuPont and obtained recommendations for three types of plastic.
Engineers simulated the product with the three materials obtained from DuPont's Web site, then, through analysis in Working Model FEA, selected the grade most likely to survive the temperature fluctuations and heavy loads. Rivadeneyra says, "The results look great, and we're confident that the latch is strong."
"Compared with we have now, we were blind," Alvarado says. "While we made very informed speculations to design a part, we were always aware that we spent too much time and money getting to our goal, which is to produce a superior product. Now when we invest in a prototype mold or a production mold, we are confident that the part will perform to our expectations."
Working Model FEA from MSC.Software is an assembly-based system that includes components for design validation, including stress and deflection, heat transfer, vibration, and buckling response. Working Model FEA also incorporates geometry-based shape optimization capabilities.
Later this year, MSC.Software will release Working Model 4D, which will combine Working Model FEA with Working Model Motion so users can perform integrated dynamic motion and FEA simulations on assemblies in one environment.
FEA WITHIN CAD
Jeff Sand, vice president of Switch Bindings (San Francisco), designs step-in snowboard bindings. And not just good ones--great ones. Just ask him. "(Our bindings) are the interface of the world's greatest snowboard boots." The company licenses the interface to NorthWave, Vans, Nike, and other top brands. Current extreme champion Axel Proporte--also known as "King of the Hill"--uses them.
Switch Bindings engineers use SolidWorks to design their products, and COSMOS/Works, a derivative of COSMOS specially designed for the SolidWorks program, to make sure they do not fail. The company chose COSMOS/ Works because of its tight integration with the CAD package, and because, says Sand, "Other products require too much specialized expertise for our engineering department to devote themselves to it."
Analysis is critical to making snowboard bindings. Typically engineers de- sign the structural frame or shank that fits inside the boots. "We have lots of existing part designs that we've tested many times in the lab, so we know various failure modes," says Sand. When company engineers design a new model, they try to recreate the loads that caused failures in past designs, then modify the geometry to improve the part. "We've analyzed every structural part we've made since we first purchased COSMOS/Works," claims Sand.
When Switch makes a completely new design, its engineers must determine whether the loads that caused lab failures of old designs will cause similar malfunctions in the new one. "COSMOS/Works pinpoints where the issues are, and we can make the necessary adjustments," says Sand. A typical example might be a component of a binding that they are trying to improve. For instance, with a high back, engineers might want to make it torsionally stiffer.
The design process at Switch Bindings starts with pencil and paper sketches. Then engineers decide which of these to model.
The company uses analysis early in the process, Sand says. "We perform analysis from the first model up to the first tooling run, and we may fill a whole 5-gigabyte drive with computer tests. We find that analysis brings information to the design process that would be very expensive to acquire through physical testing."
Switch does make fast prototypes for physical testing, as well. But, says Sand, "we can't look at ten of those per week as we can with analysis. The information we get through using COSMOS/Works takes a lot of the unknowns out of our way. It doesn't eliminate all of them, but it certainly helps to minimize them."