COMPUTER-AIDED ENGINEERING

Pressure Sciences has extensive experience in performing computer-aided engineering analysis. We use a variety of engineering software and hardware platforms which undergo nearly continuous upgrading in today's rapidly evolving computing environment. We have also written customized software for special applications, such as for evaluation of riveted storage tanks, but will normally utilize "industry-standard" computer codes for our projects.

The principal engineering codes currently used are:

• ANSYS® & LSDYNA-3D® for 2D & 3D FEA modeling and solutions to linear and non linear, large deformation, dynamic, and thermal stress problems

• CODECALC® -- The pressure vessel analysis and design program developed and marketed by COADE Engineering Software of Houston, TX. CODECALC evaluates pressure vessel components according to the current requirements of Section VIII of the ASME Boiler and Pressure Vessel Code.
  
  
• COMPRESS® -- A pressure vessel analysis and design program developed and marketed by CODEWARE Computer Systems Inc. COMPRESS evaluates pressure vessel components according to the current requirements of Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code.

Additional software is utilized as required for specific projects, including the piping programs TRIFLEX®, CAESAR II®; and Fe/PIPE® (for making 3D shell models of piping and pipe-to-vessel/tank interfaces), drafting/modeling programs AUTOCAD® and GENERIC CADD®; and the frame analysis program STAAD3®.

Furthermore, Pressure Sciences has developed proprietary engineering software to evaluate aboveground storage tanks, conventional pressure vessels, noncircular pressure vessels, and nozzles; and to perform other specialized calculations.

FINITE ELEMENT ANALYSES

Pressure Sciences provides analytical FEA support to clients who experience in-house resource limitations, or who have unique design or qualification problems on complex components. Some examples of work performed recently include:

FEA Stress Analysis of Reactor Pipe Cross

Pressure Sciences was contracted by a large Engineering and Construction firm to perform a complex 3D FEA and code qualification stress evaluation of a pressurized-cross process reactor vessel. For this job, we selected ANSYS and developed an FEA mesh of 3136, 8-node isoparametric shell elements. We were able to demonstrate that the maximum calculated stress intensities in the most critical crotch region were within allowable code limits.

Code and Fatigue Evaluation of Transit Vehicle Bolster

Pressure Sciences was engaged to perform the ASME Code evaluation of a non-circular pressure component fabricated for a mass-transit authority. We developed a 3D FEA model of the component, which functioned as a gas-accumulator for the shock absorbers in the vehicles, and documented its adequacy for static and dynamic loadings in operating and design conditions. We also performed fatigue analysis under the rules of Appendix 5 of Section VIII, Division 2 of the ASME Code. As a result of this effort, Pressure Sciences was able to document B&PV Code compliance, and to help define acceptable weld configurations.

Thin-walled shell structures

For several years, Pressures Sciences has provided analytical support for Pittsburgh Tank Corporation, a manufacturer of silos, tanks and hoppers. This work has included:

• Performing a dynamic finite element analysis of a tall silo excited by a shaker mounted at the outlet of the cone and a by a roof mounted vibrator, to determine its dynamic characteristics.
• Performing a finite element analysis of a double cone silo which had been built by bifurcating a single cone. Simple, inexpensive reinforcements were designed to alleviate high stresses in the flat plates, their juncture, and their connection to the circular silo.
• Performing finite element analyses of several leg-supported silos to determine the size and number of the legs required, to determine the size and location of reinforcement plates needed to stiffen the silo, and to minimize the size of the exterior compression ring by utilizing existing material near the cone-cylinder intersection.
• Analyzing a tall, heavily loaded silo for buckling due to seismic and wind loading and designing reinforcing rings, using the buckling criteria of the ASME Boiler and Pressure Vessel Code.

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