SACS Fatigue Ultimate

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’s may be specified by the user
• Non-tubular members, plates and shells can be included in or omitted from the fatigue analysis
• SCF’s 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’s 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.