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SACS Fatigue - Fatigue life evaluation and redesign software

Assess dynamic response with spectral and time history analysis
Automate offshore structural workflows
Calculate fatigue life
Redesign structures with fatigue data

Design for safety and reduce offshore structural failure risks

SACS Fatigue Ultimate lets you design for safety by analyzing the effects of cyclic stresses on your offshore structures. A fatigue life evaluation and redesign software, SACS Fatigue Ultimate provides you with a broad range of offshore-specific wind, wave, spectral, time history, and deterministic analysis capabilities to help you minimize the risk of failure from cyclic loads. Whether performing fatigue damage assessments for new or existing designs, you can ensure compliance with offshore codes by applying automated, fully inclusive, interactive fatigue redesign and analysis.

Assess fatigue life

SACS Fatigue Ultimate provides a variety of analyses so you can determine fatigue life from all angles. Analyze the life of your offshore structures using full non-linear soil and structural analysis, dynamic spectral/time history fatigue analysis, spectral wind fatigue calculations that include gust effects and spatial correlation and damage assessments for wave action over time.

Automate offshore structural workflows

Customizable templates within a common structural model make it easier to manage multiple analyses. Automatically pass data from one analysis step to another using industry-standard methodologies. These automated workflows simplify the management of large and complex models, which encourages your team to explore more design options.

Comply with offshore design codes

Ensure you meet international codes by using automated joint meshing or predefined industry SCF rules to calculate complex variable stress concentration factors. Assess wind and wave fatigue using standard S-N curves or ones you define yourself.

Optimize tubular joint fatigue life

Refine your structures to reduce fatigue with interactive redesign of any joint by variation of structural data and fatigue parameters. Take time-history analysis into account when assessing joint fatigue for redesign.

Simulate dynamic environments for strength and fatigue design

SACS Fatigue Ultimate includes wave response and dynamic response which simulate common dynamic environments for design code checks and fatigue damage calculations. Analyze dynamic behavior of offshore structures in random wave or user-defined environments using time history integration in wave response. Model seismic base-driven responses using design code response spectra or user-defined time history data.

Fatigue

Wave Response

Dynamic Response

Fatigue

Deterministic| Spectral| Time History Fatigue Analysis
Stress concentration factors may be automatically evaluated based on state-of-the-art theories or input by the user
Program calculated stress concentration factors may be based on API or DNV recommendations
Automatic redesign of chords and braces may be done to determine required joint can and brace stub thicknesses
The user may specify fatigue analysis for selected critical joints| excluding other joints from the analysis
Upper and/or lower limits on SCF‚Äôs may be specified by the user
Non-tubular members| plates and shells can be included in or omitted from the fatigue analysis
SCF‚Äôs can be overridden at the joint| group| member| or connection levels
API| AWS| and NPD fatigue failure (S-N) curves are built into the program. The user may| however| define his own S-N curve
The program automatically determines if a connection is K| T| or Y| KT| or X and calculates the SCF‚Äôs appropriate to that type. The user may| however| force the connection to use the SCF for any specified joint type. For example| a K brace can be forced to have the SCF of an X.
Stress ranges may be used based on dynamic or static analyses.
The program can calculate stress ranges based on the difference between stresses for maximum and minimum base shears| overturning moment| or uplift forces
Calculate stress ranges based on the difference between maximum stresses for various positions of a wave as it passes through the structure
Stress ranges may be calculated for waves of arbitrary height by automatic interpolation between values for a few waves of height specified by the user
Spectral fatigue analysis may be based on either Pierson-Moskowitz| JONSWAP (Joint North Sea Wave Project)| Lewis and Allos JONSWAP| Ochi-Hubble or user defined wave spectra
Wind fatigue analysis may be based on wind spectra
Interactive Fatigue extract file for joints with fatigue life less than the design life can be created automatically
Development of fatigue environment wave spectra from input scatter diagram information
Predict propagation of cracks
Check cross-section changes for segmented sections as in-line members
Allows expanded user defined S-N data including thickness correction and endurance limit
Includes SCF override options for wide flanges and plate girders

Wave Response

Ability to use a full structural model for use in wave response analysis.
The final steady state analysis can be obtained without a time history integration.
The effects of structural compliance can be included such that the damping effects of the fluid are automatically included.
The effects of buoyancy can be considered for floating structures.
The nonlinearities of the wave forces are represented directly.
Ability to plot wave characteristics such as surface profile| hydrodynamic forces| base shear| and overturning moment along with structural overall characteristics such as modal coordinates| velocities| and accelerations.
Plots joint and member results for user-selected joints and/or members.
Generates base shear and overturning moment transfer function and plots.
Response due to Pierson-Moskowitz or Jonswap spectra may be determined in addition to user-defined surface history.
Ability to create equivalent static loads| including both inertia loads as well as hydrodynamic loads| to be used for static analysis.
Obtains generalized modal forces from fully expanded six degree of freedom mode shapes.
Various output load case selection criteria including time of maximum or maximum minus minimum base shear or overturning moment and modal dynamic minus the modal static results.
Output of modal static and modal dynamic responses facilitates the calculation of Dynamic Amplification Factors.
Supports Airy| Stokes| Stream Function| Cnoidal| and Solitary wave theories.
Supports multiple seeds when generating surface profiles or inputting user-defined profiles.
Time history integration or Fourier decomposition methods for random wave analysis.
Perform time history analysis of combined seismic forces| wave loads| and wind turbine forces.
Includes nonlinear soil-pile interaction in the time history analysis.

Dynamic Response

Ability to use a full structural model for use in Dynamic Response analysis.
Nonlinear fluid damping effects automatically included.
Earthquake/Base-driven Analysis
- Spectral Earthquake
  - API response spectra are built into the program.
  - Supports user-defined response spectra.
  - Spectral motion can be described as acceleration| velocity| or displacement.
  - Modal combinations using linear| SRSS| peak plus SRSS| or CQC methods.
  - Ability to use a different response spectrum for each direction.
  - Automatically combines seismic results with static results.
  - Supports user-defined power spectral densities.
  - Ability to generate response function for any joint degree of freedom.
- Time History Earthquake
  - Includes earthquake time history libraries.
  - User-defined input time histories.
  - Linear| quadratic| or cubic interpolation available for the time history input.
  - Variable time step integration procedure.
  - Automatic load case selection based on overturning moment| base shear| etc.
  - Graphical representation of output variables.
  - Create a force time-history file for the combined seismic and wave response analysis.
Force-driven Analysis
- Force Time History
  - Linear| quadratic| or cubic interpolation available for the time history input.
  - Input time histories may be saved to a file.
  - Automatic load case selection based on overturning moment| base shear| joint displacement| etc.
  - Variable time step integration procedure.
  - Time history plots including modal responses| overturning moments| base shear| etc.
  - Generation of equivalent static loads.
  - Generation of incremental loads for collapse analysis.
- Periodic Vibration
  - Supports input forces and moments applied to any point at various frequencies and phase angles.
  - Automatic load case selection based on maximum joint displacement at a specific joint or at all joints.
  - Full plot capabilities including modal responses| overturning moments| base shear| etc.
- Engine/Compressor Vibration
  - Supports mechanical unbalanced forces and gas torques in addition to reciprocating loads.
  - Linear and/or nonlinear interpolation of forces between running speeds.
  - User can select specific joints to monitor or monitor all joints.
  - Joint displacements can be compared and plotted versus D-line| SNAME| and/or Military Specification allowables.
  - Allows user-defined phasing of forces and moments within a load case.
  - Can automatically combine maximum response of various load cases.
  - Generates plots of input data versus time for any load case.
  - Calculates periodic forces amplitudes and periods from force versus time input.
Spectral Wind Analysis
- Extreme Wind
  - Determines dynamic amplification factors automatically.
  - Generates common solution file containing internal loads| stresses| reactions| and displacements multiplied by its own dynamic amplification factor.
  - Includes cross correlation of modal responses using the Complete Quadratic Combination (CQC) modal combination technique.
  - Plots generalized force spectrum and response spectrum for each wind speed.
  - Uses Harris Wind spectrum.
- Wind Fatigue
  - Uses Harris Wind spectrum.
  - Optionally creates fatigue input file automatically.
  - Distributes wind speed utilizing a Weibull distribution.
  - Assumes Rayleigh distribution of RMS stresses.
  - Handles multiple wind directions in the same analysis execution.
Ice Force Analysis
- 1.2.4.1 Ice Vibration
  - Automatically includes ice stiffness.
  - Maximum and minimum peak selection.
  - Automatic cycle count for fatigue analyses.
  - Creates fatigue input data automatically.
  - Full plot capabilities including ice forces| modal responses| overturning moments| base shear| etc.
  - Variable time step integration procedure.