Issue 41

T. Morishita et alii, Frattura ed Integrità Strutturale, 41 (2017) 45-53; DOI: 10.3221/IGF-ESIS.41.07 50 (a) Before using cycle counting method (b) After using cycle counting method Figure 4 : Random loading before and after using counting method. V ISUALIZATION OF STRESS AND STRAIN PATH AND LIFE EVALUATION ased on the definition of stress/strain mentioned above, a program for visualization of stress/strain path and life evaluation under non-proportional loading was developed. C# was used as the programming code. Fig. 5 shows a flowchart of the program, that was divided into 8 categories as shown below. Figure 5 : Calculation flow in the program. (1) Input data The stress/strain data vs. time is put into the program. The input data consist of the 6 components of stress/strain and time at each column. Additional columns such as temperature can be added. Fig. 6 is the table of the input data of non-proportional multiaxial random loading formatted for the program. (1) Input data (2) Calculation of S I ( t ) and S Imax (3) Determination of reference axis (4) Calculation of  ( t ) and  ( t ) (5) (6) Cycle counting (7) Data storage (8) Life evaluation （ Calculate N f from  NP ） Figure of stress/strain path in the polar coordinate and waveforms of S I ( t )cos  ( t )- t and S I ( t )sin  ( t )- t B