safe4fatigue™ capabilities
Fatigue analysis
Fatigue analysis works directly from measured signals or peak/valley files, and produces cycle and damage histograms, cycle and damage density diagrams, stress-strain hysteresis loops, and plots of fatigue damage to show the most damaging portions of a signal.
Fatigue analysis using S-N curves
- effects of Kt
- Goodman mean stress correction
- surface finish effects
- notch sensitivity
- multiaxial fatigue analysis from strain gauge rosettes with critical plane analysis
- user-defined S-N curves and BS5400 and BS7608 S-N curves for welded joints
Local strain fatigue analysis
- uniaxial local strain fatigue analysis with Morrow and Smith-Watson-Topper mean stress corrections
- Neuber rules for stress concentrations
- critical plane local strain fatigue analysis for multiaxial stresses, with algorithms for:
- maximum direct strain
- maximum shear strain
- Brown-Miller combined shear and normal strain
- Morrow and Smith-Watson-Topper mean stess corrections using a modified Mroz cyclic hardening model
- Dang Van multiaxial fatigue analysis
- modelling grey cast iron using an incremental damage procedure
- surface finish effects
- notch sensitivity
- scale sensitivity analysis
- time-correlated damage
- ‘quick-look’ analysis of stress, strain and fatigue life
Frequency domain fatigue using PSD's as input to the fatigue analysis, with modified Dirlik/Sherrat algorithms
Single and multi-channel peak/valley analysis
- cycle omission with or without phase maintained
- peak/valley files can be plotted on a signal time-base
Calculation of principal strains and stresses from strain gauge rosette data
Generation of user-defined fatigue life curves (S-N or load-life)
Conversion of measured strain signals from one material to another
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Materials data
- a comprehensive data base of materials properties is provided
- the database can be extended and modified by the customer
- test reports and background data can be accessed
- S-N curves and strain-life data may be included
- material data can be plotted and superimposed
- advanced algorithms are provided to estimate fatigue properties
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Amplitude
- rainflow cycle counting to range-mean and range-only histograms and density diagrams
- cycle exceedence diagrams
- time-at-level, level crossing
- probability density, joint probability
- Markov from-to matrices
- range counting
- peak/valley distributions
- peak/valley exceedence diagrams
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Frequency
- power spectral density (PSD) and peak-hold PSD
- cross spectral density (CSD)
- transfer functions - gain, phase and coherence diagrams
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Filters
- Butterworth and elliptical filters, including forward / backward filtering to maintain phase relationship
- FFT filters for complex signal shaping
- spike detection and spike removal
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Signal modification
- linear and non-linear re-scaling
- multiply, divide, add and subtract data files and results files, including 3-D histograms
- integration and differentiation of signals and results (forwards and backwards)
- drift removal from integrated signals
- maths functions, including trig and other functions
- append time histories
- transform 3-axis signals to new set of orthogonal axes
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Signal generation
- generation of white noise, sine and square waves
- regeneration of single and multi-channel test signals from peak / valley files
- selectable shaping and ramp rate
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Data acquisition
- interfaces to most common data acquisition systems and data structures
- data can be acquired using SAFE data acquisition software, driving Data Translation A/D cards
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Display
- flexible graphical display
- individual, stacked and overlaid plots
- 3D histograms
- colour contour plots
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Additional features
- optimised to handle very large data sets quickly and efficiently
- ‘Explorer’ style tree view of active data files, data channels and results
- import / export to ASCII, Excel and fe-safe
- export to Microsoft? Office and other applications
- editor for signals and results files
- drag-and-drop data files from other applications
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introduction