The nozzle extension consists of a main curved wall and a reinforcing ring close to the jet exhaust, as shown in Figure 29.4: Nozzle Extension Geometry

Figure 29.4: Nozzle Extension Geometry

Both the wall and the reinforcing ring are made of layered composite materials. The model uses a single orthotropic material for all layers; however, the material orientation varies from layer to layer. The material is assumed to be homogeneous for both the thermal and mechanical analysis. This simplification could speed up the computations and provide a reasonable solution.

Because the model exhibits symmetry, optimal computational efficiency is achieved by modeling only a single 1° sector (the base sector) of the entire nozzle extension. The geometry model of the 1° sector is shown in Figure 29.5: Nozzle Extension 1° Base Sector Geometry, where (a) is the global geometry and (b) is a detail view of the reinforcing ring.

Since the thermal solution exhibits cyclic symmetry for temperature, CE can be used to accomplish this. The CE command could be used for the structural cyclic symmetry, but in this example, the DSYM command is used to demonstrate the different ways to accomplish a task in Ansys.

Figure 29.5: Nozzle Extension 1° Base Sector Geometry

The reduced 1° geometry model is meshed with SOLID279 elements. Figure 29.6: Ring Element Plot and Figure 29.7: Expanded Layer Representation of the Solid Mesh respectively show the mesh and the layer solid representation of the solid mesh (/ESHAPE).

Figure 29.6: Ring Element Plot

Figure 29.7: Expanded Layer Representation of the Solid Mesh

Using the SOLID279 element it is possible to make the element behave like a homogeneous material or a layered material (KEYOPT(3) = 0 or 1). Shell sections define the layers of the composite material. (The SECTYPE command specifies the section type, and the SECDATA command specifies the material, thickness, material orientation, and the number of integration points of each layer.) Two sections are created: one for the main wall and another for the reinforcing ring. The following table summarizes the shell section properties:

Assume that the reinforcing ring is securely bonded to the outer surface of the main extension wall. The secure bonding is easily simulated (CE/CP commands).