CAESAR II - Pipe Stress Analysis
CAESAR II is the Pipe Stress Analysis standard against which all others are measured and compared. The
CAESAR II spreadsheet input technique revolutionized the way piping models are built, modified, and verified.
CAESAR II was the first pipe stress program specifically designed for the PC environment. The interactive capabilities permit rapid evaluation of both input and output, thereby melding seamlessly into the "design - analyze" iteration cycle.
CAESAR II incorporates a wide range of capabilities, from numerous piping codes, to expansion joint, valve & flange, and structural databases, to structural and buried pipe modeling, to equipment and vessel nozzle evaluation, to spectrum and time history analysis. Most of the features of
CAESAR II are available at a keystroke, but at the same time are not imposed upon the analyst.
A menu-driven scroll and select interface provides logical options when and where expected. Context-sensitive help provides instant technical assistance for each data field, with expected units. Data values presented in the help screens are automatically presented in the current set of units to aid input.
The customization options of CAESAR II have been driven by user requests, code changes, and the need to benchmark older, existing systems and their initial design. Many of these customization options enable newer analysis techniques appearing in current literature.
As with all Hexagon PPM products, CAESAR II is continuously maintained and improved by the engineering staff. The engineering staff of
Hexagon PPM have worked in industry, for engineering and consulting firms. This experience not only guides program development, but provides users with knowledgeable support. This allows
CAESAR II to work the way a typical engineer thinks and solves a problem. This also means that the technical support provided to users by the engineering staff is almost instantaneous. Users talk straight to the developers, ensuring an accurate and timely answer.
Program revisions incorporate additional capabilities addressing both technical and operational items. Users are encouraged to suggest improvements that would help their day to day usage of the software. See the enhancement list for details of capabilities added for each release of the
CAESAR II program.
Menu / Spreadsheet Interface
The menus are set up to present the available program options in a logical order, when they are needed. Menus govern the overall flow of control throughout the program.
The input spreadsheets provide concise prompts for input data. The piping spreadsheet duplicates "elemental" data values forward to succeeding elements as the user defines them. When appropriate, databases can be accessed to obtain values for valves, flanges, and expansion joints. If desired, an expansion joint modeler can be invoked to build the necessary spreadsheets (with the appropriate tie-bar connections) to accurately simulate a variety of expansion joint styles.
CAESAR II does not enforce artificial coding rules on the user during model construction. Models can be started anywhere and can continue in any direction from tees or anchors.
The unique List Processor provides a concise method to review specific data sets, for example all the bends in the model. The fields in the List Processor tables are active, allowing user modification of the data. This processor also enables groups of elements to be "blocked," with further manipulation of the data in the block. Blocks can be rotated, duplicated, renumbered, or deleted as necessary.
Over 60 restraint types provide the most comprehensive library of boundary conditions available to the pipe stress analyst today. Support types include all of the expected linear and non-linear directional restraints, as well as: bottomed out spring hangers, large rotation rods, and bi-linear soil restraints.
The Buried Pipe Modeler allows rapid creation of complex soil models. By simply specifying the soil characteristics, and which portions of a system are buried,
CAESAR II can re-mesh the model, computing the soil restraint locations, directions, and stiffnesses as necessary.
Through the use of 32 bit compilers, the upper limit on model size is restricted solely by the amount of free upper RAM. The limits on model size are reported in the input processor, to inform the user during model construction.
The "help" facility provided with CAESAR II gives the user access to very specific information about the current input cell or menu selection. The help text details exactly what is expected, why, and when appropriate the code reference. When necessary, the help text shows the expected units for the current data cell.
The same help engine is used to provide program diagnostics in the event of system or program failures. Diagnostic messages are available for computational as well as system abnormalities.
All help and diagnostic messages provide complete contact information to ensure users have a variety of methods available for contacting the
Intergraph support staff.
The CAESAR II graphics modules are designed to provide an alternate method of interrogating the input and output
data. The input graphics module reduces most input modeling mistakes, by permitting the display of the major elemental data. Node numbers, restraints, spring hangers, nozzles, tees, bends, expansion joints, and rigid elements can all be shown graphically. Numeric data such as element lengths, temperatures, and pressures can also be displayed.
The interactive rotate, pan, and zoom features of the input module are controlled directly from the cursor pad. A "high light" option is available to selectively plot any portion of the model matching a particular search criteria, such as "all the pipe of a certain temperature."
The output graphics include standard options such as displaced shapes and colored stress plots. Additionally, the output graphics can show the direction of restraint action, and the individual details (displacements, forces, and stresses) on each element in the model as the cursor is moved through the model.
Integrated Error Checking
The CAESAR II program includes an integrated error checker, which is automatically run following the completion of the input specification. This error checker analyzes the user-specified input and checks it for consistency from both a "finite element" and "piping" point of view. Two types of messages are generated by this error checker, warnings and fatal errors. Warning messages are conditions which may be errors, but are numerically acceptable. For example, warning messages are generated when a change in direction is encountered, without a bend or tee being specified. Fatal error messages are generated when the specified input data is inconsistent or illogical, for example if the corrosion allowance is larger than the corresponding wall thickness.
Jobs can be analyzed with warning messages, but not with fatal error messages.
Interactive Report Review
Once a job has been analyzed, the solution results are available for review at any time. The review module is interactive, allowing the selective review of individual output reports for individual load cases. Reports can be generated in any units system simply by altering the configuration. Reports can be viewed on the terminal screen, or sent to a printer or to a disk file.
The CAESAR II program incorporates many databases to reduce the time the analyst spends looking for numeric values associated with piping components.
CAESAR II currently provides the following data bases:
Pipe Size Specifications:
ANSI - American National Standard
DIN - German Standard
JIS - Japanese Standard
Valve & Flange DataBases:
Crane - The Crane valve & flange data
Generic - A mixed data base from several vendors
NoFlange - Valves only
Spring Hanger Tables:
Currently there are 19 spring hanger tables from around the world available. These tables are:
Expansion Joint Catalogs:
- Grinnell (US)
- Bergen Paterson (US)
- Power Piping (US)
- NPS Industries (US)
- Lisega (Germany)
- Fronek (US)
- Piping Technology (US)
- Capitol (US)
- Piping Services (US)
- Basic Engineers (US)
- Inoflex (Italy)
- E. Myatt (Canada)
- Sinopec (China)
- Bhel (India)
- Flexider (Italy)
- Carpenter&Paterson (UK)
- Comet (UK)
- Hydra (Germany)
- Sarathi (India)
Pathway Bellows (US)
Senior Flexonics (US)
For structural modeling, CAESAR II includes a number of libraries of structural shapes. These libraries contain the necessary parameters required to build the element stiffness matrix as well as dimensioning and detailing data. The libraries installed with
CAESAR II include AISC 1977, AISC 1989, German 1989, Australian 1990, South African 1991, Korean 1990.
Graphics Display of Solution Data
Once the solution data is available it can alternatively be reviewed in a graphical format. This presentation shows how the system responds to a particular set of loads by plotting the system in its deformed position. These plots can also include restraint, force, and stress data. These graphics results can be shown on the terminal screen, sent to a printer, or saved in PCX format for incorporation into desktop publishing documents.
Custom Program Configuration
The CAESAR II program can be customized to suit individual taste or project requirements. This customization can be controlled on a directory by directory basis, accommodating different users or different client needs.
The customization options are grouped into categories, such as Text Screen Colors, Display & Printer, Computation Controls, SIFs & Stresses, and DataBases. In each category, the options are listed with their current setting. Typically, the setting of a particular option can be changed by toggling through a list valid settings. Each option is backed up by on-line help, further defining the purpose of the option and the available settings.
Interfaces to Other Programs
CAESAR II provides interfaces to most major CAD packages and several
analytical packages. These interfaces are listed below.
AutoCAD - A DXF file can be generated by CAESAR II and exported.
Cadcentre - Neutral file can be imported into CAESAR II.
- Neutral file can be imported into CAESAR II.
Isomet - Neutral file can be imported into
Intergraph CAESAR II.
PCF - Neutral file can be imported into
Neutral file can be imported into CAESAR II.
The best CAD
interface is CADWorx Plant, an AutoCAD-based drafting design package developed by
Intergraph. This package overcomes many of the difficulties found in other similar
packages plus it provides a complete bi-directional data link to CAESAR II. This
data link passes both model data and analysis results data, permitting
effortless generation of stress isometrics. Details on the design and
capabilities of this package can be found in the CADWorx Plant white papers on
this web site. Click here to download the CADWorx Plant demo.
A data file of dynamic pipe forces can be imported into the following
and Design Capabilities
CAESAR II incorporates a robust static solver, employing both the Choleski or
LDLT methods as appropriate. The static solvers are designed to iterate to a
converged solution, modifying the global stiffness matrix as the status of
non-linear restraints changes. Once the static displacement solution is
available, element forces and moments are computed, followed by the element
stress computation according to any of the 21 built-in piping codes.
In addition to the standard boundary conditions (restraints and
displacements), the user may specify either WRC-297 vessel or API-650 tank
nozzles. The flexibilities of these nozzles are computed according the
respective document, and inserted into the model at the referenced node point.
Structural steel models can be incorporated into the piping models, or solved
as stand alone models. Buried pipe and jacketed pipe models can be analyzed
also, just as easily.
The dynamics solutions include natural frequencies, harmonics, earthquake
spectra, force spectra, and time history. Once the dynamic solution has been
obtained, the animation module can be used to show the natural modes of
vibration, the harmonic response, or the motion in the time domain.
Auxiliary modules are provided to determine the acceptability of the piping
forces and moments on the boundary elements of the model. The Equipment module
includes checks for NEMA-SM23, API-610, API-661, API-560, and the HEI Standard.
WRC-107 and WRC-297 modules are provided for stress checks on vessel nozzles.
Other modules allow checking for ASME Section VIII, Division 1, Appendix 2
flanges, expansion joint rating, B31G pipelines, and AISC structural unity
CAESAR II performs stress computations on pipe elements according to various
piping codes. Currently the piping codes incorporated into CAESAR II are:
SECT III Class 2
ASME SECT III Class 3
US Navy 505
B31.4 Ch IX
Swedish Method 1
ANSI B31.1 (1967)
B31.8 Ch VIII
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