**3.1 Residual stress according to rates of shrink fit**

As mentioned above, when the copper bushing is inserted into the cylinder block to prevent the sticking, residual stress is expected before use of the product. The amount of residual stress is expected to be proportional to the rate of shrink fit. The small rate of shrink fit is likely to cause detachment of the bushing, and the large rate of shrink fit is expected to adversely affect the durability of the copper bushing and cylinder block (**Figures 5** and **6**). Therefore, it is important to select the rate of

**Figure 5.** *Bushing expected departure direction [3].*

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

**Figure 6.** *Crack of cylinder block.*

simulation methods are expected to be confirmed in the final tests performed prior

The simulation used in this study is structural simulation. The Finite Element Method (FEM) was used as shown in **Figure 4**). The finite element method is one of the powerful methods to numerically solve wide engineering problems. Solve the equation of the virtual works (Eq. (4)) using the equilibrium equations and boundary conditions equation (Eqs. (1)–(3)) in the engineering problem domain. Simulations use the weighted residual method as a way to solve this equation of virtual work linearly. By using this weighted residual method, it gives an approximate solution of the matrixed problem. At this time, since the method used to solve the matrixed problem is the node and the element, the know-how of element setting that does not distort the coordinate system of problem is important for solving

As mentioned above, when the copper bushing is inserted into the cylinder block to prevent the sticking, residual stress is expected before use of the product. The amount of residual stress is expected to be proportional to the rate of shrink fit. The small rate of shrink fit is likely to cause detachment of the bushing, and the large rate of shrink fit is expected to adversely affect the durability of the copper bushing and cylinder block (**Figures 5** and **6**). Therefore, it is important to select the rate of

to final product launch.

*Methods for engineering analysis.*

**Figure 4.**

the problem.

**Figure 5.**

**128**

*Bushing expected departure direction [3].*

**3.1 Residual stress according to rates of shrink fit**

*New Challenges in Residual Stress Measurements and Evaluation*

shrink fit suitable for the size and material of the cylinder block and copper bushing before use.
