PSI - Issue 57

851 4

Amira Aboussalih et al. / Procedia Structural Integrity 57 (2024) 848–858 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

4. Results and discussion

4.1 Cyclic behavior under strain The hardening shows a hardening behavior resulting in an increase in the stress as a function of the number of cycles and a softening in the contrary case.Let’s try to load 316 L steel for 10 cycles, under a range containing small and large imposed strain (IS) between (0.2%, 0.4%, 0.6%, 0.8%, 1%) and analyze its behavior. The results of the simulation obtained are shown in Fig 2 in the form of hysteresis curves represent the evolution of the stress as a function of plastic strain.The stress values obtained nevertheless show (see Table 2) a proportionality between the amplitude (peak-to-peak) of deformation Δε to the amplitude (peak-to-peak) of stress Δσ indicating the character of hardening of the steel studied. Fig 3 represents the relation of the peaks of the axial stress as a function of the number of cycles.

400

300

-300 Axial Stress  xx ( Pa ) -200 -100 0 100 200

 xx = 1 %  xx = 0,8 %  xx = 0,6 %  xx = 0,4 %  xx = 0,2 %

-400

-0,01

0,00

0,01

Axial Strain  xx (%)

Fig. 2. Response from 316L steel for several levels of sinusoidal strain

Table 2 : Cyclic imposed strain and corresponding stress

[%]

0.2

0.4

0.6

0.8

1

[MPa]

230

285

300

310

320

300

280

260

240

220

 xx = 1 %  xx = 0,8 %  xx = 0,6 %  xx = 0,4 %  xx = 0,2 %

200

180

160

2 Maximum Axial Stress (MPa) 4

6

8

10

Number of cycles

Fig .3. Hardening of 316L SS for different stages of strain