Aerospace and defense

Lockheed Martin Space Systems Products with NX plays a critical role in the design Femap, NX of NASA’s new Orion spacecraft

Business challenges More than 900 load cases 60-analyst team uses the sustain the crew during the space travel, associated with launch and integrated solver, pre- and and provide safe re-entry from deep space abort postprocessor to optimize the return velocities. FE models with up to one mil- design of the successor to the lion elements Orion consists of three main structures: the Space Shuttle crew module, the service module, and the High volume of results data to launch abort module. Finite element analy- sort through to determine crit- Designing the deep space exploration sis (FEA) is playing a key role in the design ical load cases vehicle of all three modules by allowing develop- Lockheed Martin Space Systems Company, ment teams to understand the loads and Keys to success one of the four major business divisions of stresses that the modules will experience Integrated FEA solver, pre- Lockheed Martin, is the prime contractor during all phases of their journey. That and postprocessor building the Orion Multi-Purpose Crew understanding is then used to optimize Vehicle, NASA’s first spacecraft designed Easy-to-use pre- and postpro- factors such as weight, stiffness, material for long-duration deep space exploration. cessing (utilizing Windows) selection, shape and strength of individual Orion will carry up to six people into space, with powerful visualization parts. provide emergency abort capability, Ability to import Pro/ ENGINEER CAD geometry Creation of custom functions using the Femap API

Results Complicated trade studies completed in two to three weeks Improved accuracy through visualization and geometry manipulation tools that help confirm the FE model was properly created

www.siemens.com/plm/femap Results continued Ability to sort through hun- dreds of load cases quickly using data ranking and free body functions Automation of routine tasks via scripts saves time and increases accuracy

Lewis and his colleagues are currently looking at 900 load cases related to different launch and abort scenarios.

“ I’ve used a lot of the commercial products, and Femap really supports the way that we use FEA.”

Joseph Hess Stress Analyst Red Canyon Engineering and Software

In many ways, this is the typical iterative computing power available. (Their FEAs process between structural analysts and run on a cluster of Linux servers.) designers, who use FEA-based trade stud- ies to optimize a design. Except in this “When I worked on an aircraft program in case, the process takes years, and the the early 1990s, we only had 100 load finite element (FE) models can be huge cases and maybe five of them were criti- (up to one million elements). Another cal,” says Eric Lewis, a stress analyst and important difference is the larger number senior staff engineer at Lockheed Martin of load cases that must be evaluated, Space Systems, who is part of the analysis which is partly a result of the complexities team working on the Orion’s service and of launching a vehicle into space and launch abort modules. “As the computers returning it to earth, and partly due to the and software have grown more powerful, “ Using Femap, you can view your model in a lot of different ways, and turn different elements and geometry on and off. This helps us doublecheck and catch mistakes.” Eric Lewis Stress Analyst and Senior Staff Engineer Lockheed Martin Space Systems

that’s allowed most of these projects to “I’ve used a lot of the commercial prod- generate a lot more load cases.” Lewis and ucts, and Femap really supports the way his colleagues are currently looking at that we use FEA,” says Joseph Hess, a approximately 900 load cases related to stress analyst with Red Canyon different Orion launch scenarios. Engineering and Software who works fulltime on the Orion project. Integrated FEA solver, pre- and postprocessor For example, because Femap is CAD- Lockheed Martin Space Systems’ FEA independent, analysts can import design software-of-choice for the Orion structural geometry created using Pro/ENGINEER® analysis is Femap™ with NX™ Nastran® software to use as the basis for FE models. software, an integrated FEA solver, pre- Femap also offers a wealth of geometry and postprocessor from product lifecycle creation and modification functions, management (PLM) specialist Siemens PLM allowing analysts to change the geometry Software. According to Lewis, Femap with if necessary prior to creating the FE NX Nastran has a lot of advantages for the models. The structural analysts create Orion analysis. coarse mesh models, which are provided “ We’re able to run several iterations each day, on models with approximately one million elements, and we’re able to perform some fairly complicated trade studies in just two to three weeks.”

Eric Lewis Stress Analyst and Senior Staff Engineer Lockheed Martin Space Systems CREW MODULE

LAUNCH ABORT SYSTEM EUROPEAN SERVICE MODULE

“ Our engineering to the loads and dynamics analysts who Time-saving functionality for determining workstations are Windows- run coupled loads involving both the critical load cases based, so it’s easy to get spacecraft and the launch vehicle. They In all, approximately 60 stress and dynam- information out of the also create models with finer meshes, ics analysts use Femap with NX Nastran on Femap models into other which are more appropriate for detailed the Orion project. (This solution is used by tools such as Excel, and to stress analyses and optimizing parts for the analysts working on the crew module, pull out pictures.” weight and stiffness. in addition to those working on the service Joseph Hess and launch abort modules.) Hess appreciates the fact that Femap Stress Analyst utilizes the Windows® operating system. Red Canyon Engineering and One of the main benefits of Femap is that “Our engineering workstations utilize Software its ease-of-use helps turn around trade Windows-based software, so it’s easy to studies quickly. “When you’re changing get information out of the Femap models one or more components and looking at into other tools such as Excel, and to pull the effects on the whole system, Femap out pictures,” he says. really helps because it’s easy to modify these full-system models,” says Lewis. The structural analysts have used the “We’re able to run several iterations each Femap application programming interface day, on models with approximately one (API) to create scripts that automate repet- million elements, and we’re able to itive tasks. One script, for example, maps perform some fairly complicated trade multiple pressure loads from one model to studies in just two to three weeks.” another. Another updates the non-struc- tural mass/area on multiple shell Lewis adds, “Another thing I like about properties to match the total actual mass. Femap is that it’s very visual. It’s so easy to Others calculate optimized shell thickness make an error in a finite element model. based on element stresses, and resultant Using Femap, you can view your model in shear forces for cbush, cbar, and cbeam a lot of different ways, and turn different element output. Solutions/Services elements and geometry on and off. This the Femap free body tool, which is an Femap with NX Nastran helps us double-check and catch mistakes.” extension to the postprocessing toolbox www.siemens.com/plm/femap that allows easy creation of free body Several aspects of Femap are particularly diagrams and investigation of interface valuable on this project because the high loads. “We like the free body tool because Customer’s primary business number of load cases requires a lot of we can do section cuts through the vehicle Lockheed Martin Space sorting of the results data to figure out at different stations and figure out the Systems Company is one of which load cases are critical. The data load paths to see what types of loads are the four major business divi- ranking function in the Femap data table, in the different areas very quickly,” Lewis sions of Lockheed Martin. for example, can be used to sort the data explains. www.lockheedmartin.com/us/ and show the maximum and minimum ssc.html very quickly. This eliminates the need to Lewis describes himself as a “Femap cham- export results into an Excel software file pion,” spreading the word about the Customer location and create minimum and maximum func- advantages of Femap among his aerospace tions. “The data table does that for you,” colleagues. “I tell them how easy it is to Denver, Colorado says Hess. “It’s a huge time savings.” use, and easy-to-learn,” he says. “That United States Femap is very powerful and intuitive Another tool that can be used to narrow software.” down the number of critical load cases is

“ We like the free body tool because we can create section cuts through the vehicle at different stations and figure out the load paths to determine what types of loads are in the different areas very quickly.”

Eric Lewis Stress Analyst and Senior Staff Engineer Lockheed Martin Space Systems Siemens PLM Software

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