*2.3.3 Boundary conditions*

Symmetry boundary conditions were applied as shown in **Table 3**.

**27**

**Table 3.**

**Table 2.**

*Symmetry boundary conditions.*

*Sustainable and Efficient Hydroforming of Aerospace Composite Structures*

A homogenous pressure of 165 MPa is applied to the inner faces of the yoke

Frictional contacts were defined between the yoke plates and the winding frame (**Figure 3c**). A tie constraint was used to bond the winding frame and the composite winding, as it is assumed that no movement occurs between these two

Section "A" is a pure circular cross section imitative of that of commercially available hydroforming machines with similar operating pressure capabilities. However, these dimensions must be optimized for the use of composite winding

The test matrix for the Section "A" optimization is presented in **Table 4**. The non-horizontal angled cut contact interface between yoke plates is introduced as an additional design variable with the intention of reducing yoke plates stress, while

Following the results obtained from the analysis of section "A," the finite element model assembly was modified. The new assembly is essentially the same as the original, with the exception that the press cylinder has been removed, and the yoke plates were extended to fill out the space of the press cylinder. The same materials are used for each component. Likewise, the same symmetry conditions and load

Elastic modulus 1 E1 134 GPa Elastic modulus 2 & 3 E2, E3 129 GPa Poisson ratio Nu12, Nu13, Nu23 0.34 Shear modulus G 4.84 GPa Density Rho 2.81e−9 Failure stress σ 1903 MPa

the press cylinder thickness is reduced until it is completely removed.

**Symmetry plane Degrees of freedom**

*Composite winding material properties (Zoltek Panex 35 carbon Prepreg [30]).*

X 0 Free Free Free 0 0 Y Free 0 Free 0 Free 0

**Translation Rotation Tx Ty Tz Rx Ry Rz**

*DOI: http://dx.doi.org/10.5772/intechopen.81505*

*2.3.4 Loading conditions*

*2.3.5 Contact definition*

*2.3.6 Section "A" test matrix*

instead of the traditional pre-tensioned steel wire.

*2.3.7 Updated finite element model without press cylinder*

components.

cases are applied.

plates as shown in **Figure 3b**.

*Sustainable and Efficient Hydroforming of Aerospace Composite Structures DOI: http://dx.doi.org/10.5772/intechopen.81505*
