Software description

Specific features of dPIPE Analysis:

Static Analysis:

• setting an unlimited number of system’s operating modes with a subsequent automated procedure for calculations of the stress ranges;
• advanced procedure for spring hanger design: selection of springs from the variety of manufacturer’s catalogues, ability to define preset load for any operational condition (“cold installation”/design/cold), etc.,
• modeling of the non-linear boundary conditions: support lift off, gap closure, friction, pendulum and large deflections effects for the rod and spring hanger supports.

Dynamic Analysis:

Response Spectrum Method:

• Multi Support Excitation;
• different options for modal combination (SRSS, CQC, 10 %);
• seismic anchor movement;
• missing mass effect (static correction for modes above cut-of-frequency);

Time History Analysis:

• 3D Acceleration Time Histories;
• transient dynamic loads;
• nonlinear dynamic supports (viscous dampers, snubbers, limit stops)

Vibration Analysis:

• modal assessment procedure;
• susceptibility method

Piping calculational model could be developed in a different ways:

1. with use of specialized “piping” language (set of commands stored in the ASCII text file);
2. with use of WINDOWS based dPIPE Design Environment (DDE) - interactive electronic spreadsheet that combines capacities for data entering and synchronized browsing of the piping model. Main features of this interactive interface are:
• ease of use;
• multi-windows interface with synchronization of the numerical data entered in tables and graphical visualization of the model;
• option for the input data entering in the dynamic “tracing” mode
• intuitive interface;
• option for use the custom-defined databases and standard catalogues for piping fittings and supports
• built-in calculator;
• automatic generation of the nodes names and numbering

3. by conversion of third party Design or CAD data to dPIPE input

The library of elements used for creating a piping model comprises from the following items:

PIPE – straight pipes
BEND – curved pipes, elbows and miters
REDUCER
VALVE - options: modeling of the actuator, half valve, angular valve, assessment of nozzle loads
EXPANSION JOINT - options for different types: Universal (EJ), Axial (EA), Tied (ET), Hinged (EH), Gimbal (EG)
RIGID - options: rigid link, “thick” pipe
FLEX - Modeling of Nozzles
STRU - Structural Element, beam

Piping supports could be modeled with use of the following elements:

ANCHOR: This support is used for modeling of piping attachments to the civil structures or equipment. Options for output results in global and local coordinate system, RELEASE option for spring hanger design
SUPPORT: general support with 6 stiffness components. Could represent a fix point in span of piping, options for output results in global and local coordinate system
SPRING HANGER: Modeling of existing spring hangers/supports and spring design for new supports. Option for individual adjusting of criteria used for spring design (different spring tables, variability and load factors), consideration of swinging and large deflections effects
ROD HANGER: rigid suspension, works only one way, consideration of swinging and large deflections effects
SLIDING: sliding support taking the weight of the pipe, restrains vertical movements, options for friction, gaps and one-way operation. Could be set in global or local coordinate system
GUIDE: Guide support. Restraining of all translational piping movements except the axial. Options for one way operation in vertical plane and friction.
RESTRAINTS: general class of supports acting along its axes. Options for gaps and friction
DAMPER: 3D damper support. Active only for dynamic loads. Used for modeling of High Viscous Dampers. Selection from GERB Catalogue for VD and VES dampers. Three different mathematical models: elastic, ideal viscous and Maxwell
SNUBBER: dynamic restraint inactive for static loads, different models for mechanical or hydraulic snubber
RIGID STRUT: 1D restraint with options for geometrical nonlinearity

Peculiarities for analysis and post-processing specifications and options.

dPIPE provides flexible tools for setting an analysis options. User may form a necessary number of Load Cases under combination of the following loads:

• weight;
• internal pressure;
• thermal expansion loads;
• equipment and supports temperature movements;
• preset loads from spring hangers;
• cold spring loads;
• seismic or dynamic loads

A global options may be defined for the whole set of analyses:

• use of Hot or Cold Young Modulus;
• interpretation of the preset load for spring hangers: design, cold, or theoretical installation load;
• use pressure for calculation of the bends flexibility factor;
• uniform scaling of the friction coefficient for all supports , etc.

Apart of that a local options may be assigned for each individual Load Case:

• interpretation of the supports nonlinearities (linearization, nonlinear behavior, being active or not depending on results from the previous Load Case) ;
• option for pendulum effect for variable spring and rod hanger supports;
• use or not friction for supports reaction calculations.

Specification for post-processing defines results to be printed for displacements, internal forces, supports reactions and code dependent stresses. Results (Load sets) could be formed from all calculated load cases and their combination as well

Calculational model and results of analyses could be viewed in the dPIPE browser, freely distributed program PIPE3DV that may undertake the following operations:

• zoom, moving, rotation of the model;
• 3D visualization;
• selective displaying of different groups of elements;
• show the local coordinate system used for element;
• search node number;
• quick information for nodal and element data;
• spreadsheets with results;
• stress visualization;
• addition of the user-defined text on the picture with piping model;
• dimensioning and visualization of the deformed state;
• browsing and animation of the mode shapes and forced vibration;
• export of pictures via the clipboard or saving the graphic files;
• DXF export;
• record of animation in the multimedia files

View the results of analysis (stresses)

View the results of analysis (displacements)