**4.3 Durability assessment of cylinder block considering residual stress**

The durability assessment of the cylinder block was finally evaluated by using the stress simulation result considering the residual stress, the use environment and the allowable stress which is one of the characteristic values of the material. At this

time, among the many durability assessment methods, the mean stress is constant in the cylinder block, and the stress condition during use is relatively simple, so that it is calculated according to the criterion of σ<sup>m</sup> = C in **Figure 25**. Finally, in order to improve the accuracy of fatigue safety assessment, size factor, slope of surrounding

**Figure 22.**

**Figure 23.**

**Figure 24.**

**139**

*Extreme situation during usage.*

*Durability Assessment Considering Residual Stress DOI: http://dx.doi.org/10.5772/intechopen.90298*

*Durability assessment results of cylinder block.*

*Comparison of durability assessment results.*

*Durability Assessment Considering Residual Stress DOI: http://dx.doi.org/10.5772/intechopen.90298*

**Figure 22.** *Extreme situation during usage.*

**Figure 23.**

**4.2 Comparison of simulation results considering residual stress**

*New Challenges in Residual Stress Measurements and Evaluation*

lowest stress (0 MPa).

*Boundary condition for FEM.*

**Figure 20.**

**Figure 21.**

**138**

*Working load of main pump.*

During operation of the main pump, the load acting on the cylinder block does

not act as a cyclic symmetry, and the load distribution during rotation varies. Therefore, in this study, the time when the cylinder block receives the highest load during rotation is selected and analyzed (**Figure 22**). The reason for this is that the cylinder block will rotate and receive a load at this peak time periodically at the

The results of the residual stress analysis obtained above are mapped to the structural simulation model and the results shown in **Figure 23** can be obtained by using the above described simulation conditions and methods. It can be confirmed that there is a considerable difference by comparing it with the stress value of the simulation method which does not consider the residual stress (**Figure 24**).

The durability assessment of the cylinder block was finally evaluated by using the stress simulation result considering the residual stress, the use environment and the allowable stress which is one of the characteristic values of the material. At this

**4.3 Durability assessment of cylinder block considering residual stress**

*Durability assessment results of cylinder block.*

#### **Figure 24.**

*Comparison of durability assessment results.*

time, among the many durability assessment methods, the mean stress is constant in the cylinder block, and the stress condition during use is relatively simple, so that it is calculated according to the criterion of σ<sup>m</sup> = C in **Figure 25**. Finally, in order to improve the accuracy of fatigue safety assessment, size factor, slope of surrounding
