Accupak/VE Release 12 Makes Mechanical Event Simulation Possible

Accupak/VE Release 12 Makes Mechanical Event Simulation Possible‡

Features Overview*

Algor Accupak/VE†

The general contact element is a powerful tool that enables engineers to combine contact, coupling and dashpot functions in one set of elements.
Material-based damping for 3-D brick, truss and contact elements enables users to simulate the dissipation of energy as a result of strain changes.
Modeling for a Mechanical Event Simulation with plate/shell elements is now easier and faster because of a new shell element solution method.
Traction, used to simulate wind shear and other phenomena, is now easier because it is no longer necessary to specify a spatial point signifying the side of the surface on which to apply the traction. That is because the software automatically recognizes the outside direction.
The Accupak/VE processor is more robust and includes a faster impact plane algorithm, thus reducing analysis run times.
2- or 3-D hydrodynamic elements enable engineers to study everyday fluid-structure interactions in a Mechanical Event Simulation, without considering fluid mechanics in detail.
The new General von Mises nonlinear material model provides an enhanced stress-strain curve that better represents the physical behavior of many materials beyond the yield point. The General von Mises material model is used in nonlinear analysis for materials subjected to large strain that follow a stress-strain curve, such as metals and alloys. During FEA preparation, engineers simply input standard test data, including Young's modulus, the material's yield stress, ultimate/breaking stress and ultimate/breaking elongation.
The new viscoelastic material model for 3-D elements complements the viscoelastic model already available for 2-D elements, enabling engineers to model creep according to the "Power Creep Law."
The material model for geological materials such as concrete has been enhanced to handle a highly detailed, user-defined stress-strain curve. Geological materials that behave differently in tension than in compression can be simulated using this material model.
Multiphysics analyses are easier because multiple processors can share the same geometry file, but results from different analysis processors are stored in separate files distinguished by unique file extensions. Once the engineer specifies the material(s) used in the model, material data is readily available for all processors thanks to the new, centralized material library.
2- and 3-D kinematic elements, an add-on to Accupak/VE, are now available. Kinematic elements result in massive processing speed gains in Linear or Nonlinear Stress Analysis or Mechanical Event Simulation scenarios involving motion, which is especially important when working with complex models such as CAD solid models and assemblies.

Algor's Release 12 Single User Interface

Superdraw III is now Algor’s single user interface from which you can access all of Algor’s modeling tools, automatic surface and solid FEA meshing and analysis options.
The "Model Data Control" window in Superdraw III gives engineers access to the new data entry screens and enables engineers to initiate pre-processing, analysis and post-processing functions all from one window.
The unit system, such as S.I. or English (inch-based), can be selected with one mouse click.
Numerical data is stored and displayed in the same format as entered. For example, "1.2e-3" is displayed that way, not converted to ".0012."
Data checking performed as the engineer enters data prevents runtime errors during analysis processing.
Each data input screen contains all of the entries required, and only those required, for a particular subject of operation, indicating mandatory items with a red dot to facilitate ease of use.
All entered data is checked against reasonable value limits, and messages "alert" the engineer of unreasonable values.
The pre-processing data entry screens enable engineers to select some parameters from pull-down lists, eliminating input errors and the need to reference separate documentation.
A final check for all required values is conducted prior to processing.
Engineers can access context-sensitive help messages with a single right mouse click on each field of a data entry screen.
All numbers referring to physical quantities are displayed with their units.
The unit system, such as S.I. or English (inch-based), can be selected with one mouse click.
New technology enables engineers to work within CAD solid modelers, such as SolidWorks and Mechanical Desktop, when the CAD system and Algor are on the same computer. With this advancement "Algor" is a simple menu selection that gives engineers access to all of Algor’s FEA meshing and analysis capabilities.
Algor works with native CAD geometry files, such as Parasolid or ACIS, when Algor is operated on a computer other than the one on which the CAD system is installed.
The new feature line adjustment tool in Superdraw III enables engineers to quickly and easily change or remove feature lines. Removing small, irrelevant features is a common technique for reducing the number of elements in a CAD model. A complementary Merlin enhancement bases surface mesh enhancement only on feature lines while preserving all surface information.
Algor continues to work with universal files, such as IGES or STL, and offers the ability to view and verify the quality of universal file geometry before FEA meshing.
A new capability enables engineers to match the surface meshes on the shared interface, or "border," between groups in a multi-group model (helpful for CAD assemblies and models using multiple materials).
A new capability enables engineers to individually create a solid mesh for each group within a multi-group model (helpful for CAD assemblies and models using multiple materials).
A new option enables engineers to create a high-quality, solid, hybrid mesh without pyramid-type elements.
Add, edit, delete and manage material property data through an easy-to-use Material Library Manager interface.
Material information is stored in centralized files for use by all Algor processors.
Material data is subject to the same data checking standards as data entered through data screens.
Engineers can create custom libraries with the Material Library Manager.
Algor provides a default material library with values drawn from standard engineering references for a wide variety of common materials.
The "Model Data Control" window in Superdraw III has a new "Material" field that enables point-and-click material application to groups of elements.
The material libraries preserve the material's original unit system and Superdraw III automatically converts information to the active model's unit system.
The new material library is stored in a standard X-base database file format, making it possible for customers to interface with company material data in other databases through custom applications.
DocuTech, Algor’s software documentation system on CD-ROM, has updated content for Release 12 software.
The DocuTech interface has been integrated into a single window consistent with advanced Windows applications.
DocuTech information has been reorganized for quicker and easier access.
An enhanced DocuTech search utility enables engineers to limit searches.
Additional DocuTech print capabilities enable engineers to print sets of linked pages such as chapters or whole sections automatically.

* This is not intended as a complete list of Accupak/VE or Release 12 features, just an overview. For a detailed description of all Release 12 features, contact the company and/or see Algor's website at www.algor.com.

† Algor offers Accupak/MES, Accupak/NLM and Accupak/VE. Accupak/MES dynamically and simultaneously replicates motion and flexing with resulting stresses all in one package. It predicts deflection, deformation and displacement where material nonlinearities are not a concern. Accupak/NLM performs linear and nonlinear static stress analysis using powerful linear and nonlinear material models to predict deflection, deformation and displacement. Accupak/VE combines the Mechanical Event Simulation capabilities of Accupak/MES with the additional nonlinear material models included with Accupak/NLM.

Keith J. Orgeron, PE
Principal
Integra Engineering, Inc.
Houston, TX

Algor's new Release 12 version of Accupak/VE for Mechanical Event Simulation (MES) and Nonlinear Stress Analysis is a powerful software package for realistically simulating motion in actual mechanical events, without sacrificing realistic elastic body responses. This state-of-the-art engineering tool makes it possible for my engineering consulting firm to perform PC-based simulations and analyses that conventional Finite Element Analysis (FEA) packages just do not offer. Incredibly, the transition from such older methods is not only painless, but rather exciting because MES offers more possibilities.

Although I beta-tested Algor's Release 12 MES software last year, the production version, now shipping, has been enhanced even further. Algor's Release 12 interface graphically and logically lays out your input options using common engineering terms. The result is that you can intuitively navigate through a mechanical event simulation without needing to study each software tool in advance.

Accupak/VE Eliminates Simplifying Assumptions

By simulating mechanical events, Accupak/VE can eliminate the need for classical, rigid body motion, simplifying assumptions that make engineers doubt their answers when the phenomenon being modeled has not been previously studied in depth. Any such respectable set of simplifying assumptions takes valuable time to develop and document, and always limits achievable accuracy. Then, the engineer must remember to revise and recheck all of the simplifying assumptions with each change to the event being modeled. By eliminating this activity and maximizing accuracy, Accupak/VE helps my firm to successfully compete in today's high-tech market with equally high customer expectations.

Accupak/VE for Mechanical Event Simulation and Nonlinear Stress Analysis realistically simulates motion in actual mechanical events, such as the interaction of these gears, producing stresses at each moment in time.

Algor's new General Contact Elements, available as part of Accupak/VE, are the key to simulating mechanical events involving contact and impact, such as drop tests, multi-body impact events and the interaction of independently moving parts of an assembly. Prior to Release 12, it was possible to simulate contact and impact scenarios with Algor using a more cumbersome truss element technique. The intuitive General Contact Element data input screen uses common engineering terminology and simplifies the setup. Unlike truss elements, General Contact Elements take into account a lot more than just contact. General Contact Elements can be used to simulate coupling, replicate a dashpot or a spring or take damping into account. In addition, the General Contact Element can apply varying properties based on whether the element is in compression or tension. These elements can be automatically generated between selected objects within Superdraw III, Algor’s single interface for FEA and precision finite element model-building tool.

Algor's General Contact Elements enable engineers to simulate events involving interaction of several objects, such as the gears shown here. The intuitive General Contact Element data input screen uses common engineering terminology for easy setup.

One of my favorite Accupak/VE features is the automatic time-stepping option for mechanical event simulations. The numerical convergence routines almost take care of themselves, so that very little knowledge about the actual event or response is required in advance. Algor also utilizes the more capable, implicit integration scheme for its Accupak/VE processor - but you don't have to be able to teach a course on nonlinear integration schemes to make use of Accupak/VE's power. After 17 years of FEA work using four different packages and reviewing many analyses from about six other packages, I have yet to see a better engineering tool for modeling mechanical events and stress analysis.

For example, I recently modeled the operational collapse behavior of a large, 57-foot hydraulic cylinder assembly that was uniquely configured to perform hoisting with wire rope sheaves mounted at the head of the cylinder. This event included a variety of forces, moments (at the rod end), gravity and dynamic (at sea) motion inputs applied and ramped at various times to simulate a worst case but realistic scenario. Nonlinear material properties, large deflection, large strain, and a tight convergence tolerance were required features. After a nonlinear modal frequency analysis, several runs and a few restarts, I could report that two separate models of the cylinder, one comprised of brick elements and another of beam elements, resulted in only a 2.5% variation in the collapse load. Certification of the equipment soon followed. Algor's package makes it possible for me to quickly become an "expert" in the phenomenon being analyzed because there's so much data available so fast. All of my reports are delivered with brilliant graphics captured from Algor's post-processing software, Superview. A colorful stress plot of the buckling cylinder’s geometry with the rod’s local yielding stresses near the point of collapse graced the cover of my report on the example described above. Algor software can automatically produce movie clips of the full motion event, which often highlight trends that aren't obvious from individual stress contours. These graphics and movie clips are critical to present proposals, ideas and results to my customers who in turn use them to help sell their products!

Single User Interface and Data Input Screens Support Accupak/VE

Honestly, no engineer can utilize but a few engineering software tools and expect to remember every command, data set, approach, etc. for all of them. And so, quite often we begin an analysis with having to remember or "relearn" these things. Algor's historical development approach seems to have been based on the premise that engineers shouldn't have to remember every option and command, and thus, Release 12 culminates in making this relearning process more of a natural recall.

Algor's user-friendly Release 12 single user interface for Accupak/VE enables my firm to efficiently develop and manage a shared, in-house material database, starting with the extensive one provided by Algor. The new-style Release 12 data input screens group related information, weed out mutually exclusive options, make some parameters available in pull-down lists and perform live data checking as input is entered, preventing processing errors. Red dots flag errors and call the engineer's attention to required items.

The interface lays out all of the options and displays numbers referring to physical quantities with their units. The context-sensitive help messages that appear with a single right mouse click provide additional information about each data field.

As a single user interface, Superdraw III brings together CAD interfacing choices and Algor's finite element meshing options, which you could label as "manual, semi-automatic and automatic." These three meshing modes give the critical control over node placement required for good models, as opposed to the "black box" approach seen with some other automatic meshers. In addition, Superdraw III includes real-time rendered viewing of surfaces with some rather fast graphics.

Superdraw III also has a lot of convenient touches like the capability to save settings and configurations with each model file so that the toolbars and views you were working with will be there for next time.

Looking Forward to What's Next

Release 12 is impressive and I was satisfied with its performance. However, I am looking forward to the next upgrade of Superview*, Algor's post-processing software, which was not significantly overhauled in Release 12. I anticipate that the post-processor will soon have the same easy-to-navigate interface as Superdraw III.

Keith Orgeron of Integra Engineering, Inc. in Houston, Texas, is a consultant who frequently uses FEA-based simulation software for design/analysis projects. He is a Registered Professional Engineer in Texas with primarily design, testing and project experience in heavy equipment for the oil and construction industries.

* Editor's note: Superview has been upgraded to have the same easy-to-navigate interface and dynamic viewing functionality as Superdraw III.
‡ Editor's not: The capabilities of Accupak/VE can now be found in the Professional MES/NLM core package, along with many enhancements.