内容分析msc.patran courses课程

1、SECTION 24MISCELLANEOUS FEATURESMULTIPLE S-N MEAN STRESS CURVESMULTIPLE S-N MEAN STRESS CURVESMSC Fatigue allows fatigue analysis with multi-mean stress curves. These curves (S-N curves for different R-Ratios) which account for mean stress effects in S-N method by Goodman, Gerber or other empirical

2、methods. An ASCII Materials database (.mnd) is used, instead of the standard Materials database (.mdb)MEAN STRESSESmean stressstress rangestresssmaxsminmean stress ratiomean stressR ratioLoading conditionR1smax and smin are negative,negative mean stressR=1Static loading 0R1smax and smin are positive

3、, positive mean stressR=0Zero to tension loading, smin = 0R=-1Fully reversed, zero mean stressR0abs(smax) abs(smin),smax approaching zeroR infinitesmax = 0R-ratio = -0.5R-ratio = +0.5MEAN STRESS USING MULTIPLE S-N CURVES Damage is calculated from appropriate S-N Curve, or by interpolating between cu

4、rvesMULTIPLE S-N MEAN STRESS CURVES MULTIPLE S-N MEAN STRESS CURVES (CONT.)If S-N data at different mean stresses does not exist, corrections to the stress range can be applied to allow the use of a S-N curve determined at R=-1. Methods includeGoodman GerberWHEELS MODULE(FATIGUE OF ROTATING STRUCTUR

5、ES)WHEELS MODULEThe Wheels Module (FEROT) is a specialised module that analyses the fatigue life of rotating structures us S-N methodThe FEROT module performs a critical plane S-N analysis using surface resolved stresses at every surface nodeIncludes Goodman and Gerber mean stress correctionsUser ru

6、ns multiple static analysis with the loads rotated around at given increments, eg, 36 cases with load rotated 10 degrees per incrementWHEELS MODULE (CONT.)Multiple solutions performed to obtain stresses for each node at various positions relative to the load.Stress at Node n12.3635.36 static load ca

7、ses analysedSETUP WHEEL FATIGUE ANALYSISSELECT ROTATING LOAD CASESRESULTS FROM ROTATING FATIGUE ANALYSISTEMPERATURE CORRECTED FATIGUETEMPERATURE CORRECTED FATIGUEFatigue Properties vary with temperature, especially for components operating at high temperaturesMSC Fatigue enables a temperature map to

8、 determine material fatigue properties.A set of fatigue curves is used to define fatigue material characteristics at different temperatures.Stress-Life and Strain-Life is supported.Temperatures are steady state (i.e. no time varying or creep effects)Temperatures may vary spatially, across the FE mod

9、el.Temperatures are read from standard FE results files or ASCII table.TEMPERATURE CORRECTED FATIGUE (CONT.)AEROSPACE SPECTRUM FILE SUPPORTAEROSPACE SPECTRUM FILE SUPPORTStress Spectra are generated from information in ASCII editable:Spectrum (extension .spe); and Load Control (extension .lcs) files

10、.AEROSPACE SPECTRUM FILE SUPPORT (CONT.)Invoked by selecting Load Spectrum from the Job Setup Menu (in the Loading Information Form)DUTY CYCLE ANALYZERDUTY CYCLE ANALYZERDuty Cycle enables a schedule of multiple events to be consideredEach event can have its own number of repetitions, and damage is

11、linearly summedLoad time histories can be in DAC, or RPC, format or combinationEnables insight into contribution from individual eventsManages all the fatigue analysis runs and combine resultsDUTY CYCLE ANALYZER (CONT.) Select Duty Cycle from: Job Setup (in Loading Information Form)DUTY CYCLE JOB SE

12、TUP MSC FATIGUE FILESMSC FATIGUE FILESjobname.finJob Control File (ASCII) written by Patran, when you press the APPLY button in the Job Control Form, with the Action set to: Full Analysis, Partial Analysis, Translate Only, “Save Job Only. It defines the analysis setup as you fill out the various for

13、ms. jobname.fesInput File (Binary) File for the Fatigue Solver modules. It contains information necessary to run a complete fatigue job. It is created by the Translator (PAT3FAT), which reads the file, jobname.fin, and the FEA results information (e.g. stresses) from the model database file (model.d

14、b). TheFull Analysis, or Translate Only” Action on the Job Control Form will create this file.jobname.fppThis File (Binary) contains the result of the Rainflow Cycle Count (Preprocessing). The Action, Partial Analysis, on the Job Control Form will create all files upto this point, and stop. jobname.

15、fef Output File (ASCII) containing the Results of the Fatigue Analysis, when a Full Analysis is requested. It can be read into Patran to display the results. It is also used by the MSC Fatigue Results module, PFPOST, to do tabular listing of Fatigue results.jobname.fef_tmpl Template File (ASCII) use

16、d in reading the Fatigue Results into Patran. This contains infromation defining the meaning of the various results data in the jobname.fef file. MSC FATIGUE FILES (CONT.)jobname.msgMessage File (ASCII) containing all messages during an analysis. If the job does not run, this is the file to look at,

17、 for clues.jobname.staStatus File (ASCII), read by the Monitor action Job from the Job Control Form. This is updated constantly, as the Analysis progresses.MSC FATIGUE FILES (CONT.)MSC FATIGUE FILES (CONT.)WORKSHOPSThe following workshops are available if time is available and this topic is of interest to you“WS8: Design Philosophies (S-N, E-N & LEFM)” “WS9: Multiple Loads (S-N & LEFM)” “WS12: Wheels M