FEA Engineering White Papers

Here you will find an assortment of FEA white papers and presentations produced by the Predictive Engineering staff on topics such as Fracture Mechanics & FEA, Small Connection Elements, Linear & Nonlinear Buckling Analysis, RBE and Modeling Composites.

White Papers

  • Bolt Preload with Femap and NX Nastran Image

    Bolt preload adds quite a bit of complexity to any model since the analysis procedure is nonlinear (geometrically nonlinear) and that two sequential nonlinear runs are required to arrive at the final “bolt preload solution”. The utility of this approach lies in its ability to quantitatively calculate the bolt axial and shear forces for any type of bolted connection. Additionally, if bolt fatigue is important, then a bolt preload approach is invaluable.

  • Fracture Mechanics and Finite Element Analysis Image

    Determining the basic parameters for a fracture mechanics analysis is easily accomplished using finite element modeling techniques. Nonetheless, the engineer must be cognizant of the limitations of both technologies for their rational use.

  • Fracture Mechanics of Glass Image

    Glass is a fantastic material for subsea use. It’s incredibly strong in compression, transparent, and also relatively light.

  • Linear and Nonlinear Buckling Analysis and Flange Crippling Image

    This white paper will walk you through the NX Nastran Buckling Analysis techniques and show you how to validate your linear buckling analysis with a non-liner static analysis. Additional examples are presented on flange crippling and then finally the application of these techniques to the buckling analysis of an eight-passenger, deep-diving luxury submarine.

    Download support files (508 KB ZIP)

  • Linear Dynamics Image

    This article, reproduced from a three-part series in Desktop Engineering magazine, is a great introduction to the power of Finite Element Analysis.

  • Linear Dynamics Image

    In Part 2 of the Desktop Engineering magazine article, we explore vibration analysis and how it can show detailed structural behavior under dynamic loading.

  • Linear Dynamics Image

    In Part 3 of the Desktop Engineering magazine article, we look into extracting real quantitative data to anticipate everything from earthquakes to rocket launches.

  • Mastering RBE Elements Image

    This set of notes taken from one of our technical web seminars, condenses down in a logical fashion the very complex behavior of multi-point constraints which form the numerical foundation of RBE2 and RBE3 elements. Examples are presented to illustrate good and bad modeling practices.

    Download model files (24.4 MB ZIP)

  • Modeling Composites Image

    Modeling Composites with Femap: An Introduction to The How’s and Why’s
    Three methods for analyzing composites are explored. Each method has its good points, and some are more generally effective than others. Each has its own set of assumptions and limitations.

    Using classical plate theory to model honeycomb panels can be effective, but it certainly has limitations and it should not be construed to be capable of handling all of the general cases that the more expansive laminate theory can.

  • Principles of Vibration Analysis Image

    Linear Contact Analysis: Demystified
    Vibration analysis is a huge topic and is easily the second most common type of FEA analysis after the basic static stress analysis. Within the field of vibration analysis, the most common type of analysis is that based on the linear behavior of the structure or system during its operation. That is, its stress/strain response is linear and when a load is removed, the structure returns to its original position in a stress/strain free condition.

  • See Analysis Data's True Colors Image

    This article printed in Desktop Engineering's March 2011 edition is helpful when it's time to convince upper management to trust finite element stress data results. The paper explains why you don't always get what you want—and how to get what you need when analyzing data's true colors.

  • Small Connection Elements (RBE2, RBE3 and CBUSH) Image

    This white paper assumes that the reader has the basics of FEA down pat and an inkling of how R-elements work. The objective is to describe in detail how to use R-connections and CBUSH elements correctly and with confidence. If you make it through this note, you’ll most likely know more about these little connections than 99% of your peers.

  • Springs (CELAS) versus CBUSH Elements Image

    There is no "versus", the only spring element that I use is the CBUSH. Why? If you use the standard NX Nastran spring element between non-coincident nodes, you have the potential to suck force out of your model; that is, your OLOAD won't match your SPCFORCE in the F06 file and your model is thus garbage. I made this mistake once and was schooled by senior analyst at Navistar when she noticed that my model had some strange stresses. This technical note provides the necessary foundation to easily use CBUSH spring elements in all types of FE models.

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