## 3.1. T-Joint

T-joints are used to bond a primary structure to a secondary one. A good example is a frame with a stringer of a boat hull. Oriented Selection Sets (OSS) allow you to define complex laminates by an intuitive approach. For an example of a T-Joint analysis, see Example: T-Joint.

The laminate of a T-joint can be split into several sublaminates:

- Base plate (skin)

- Stringer (frame)

- Bonding

- Cover

Figure : T-Joint Lay-Up

The laminate is modeled by defining different Oriented Selection Sets for the different regions. The modeling plies are then associated with the OSS and their order defines the stacking sequence of the laminate.

The first OSS is defined for the base. The offset direction of this OSS shows from top to bottom as shown in Figure : OSS for the Base Plate.

Figure : OSS for the Base Plate

The OSS of the string has an orientation parallel to the global X-direction as shown in Figure : OSS for the Stringer.

Figure : OSS for the Stringer

The OSS feature allows you to define several offset directions for one element: OSS can overlap and can have different orientations. This functionality is used to define the offset direction for the bonding layers as shown in Figure : OSS for Bonding Plies. The offset direction of the base plate is different if compared with Figure : OSS for the Base Plate.

Figure : OSS for Bonding Plies

In addition, the OSS feature allows you to define the reference directions for complex shapes (twisted surfaces, right angles). The reference direction is computed from one or several reference coordinate systems (CSYS) as shown in Figure : Reference Direction. In this case two CSYS are selected.

Figure : Reference Direction

After all the necessary OSS are defined, define the Modeling Plies in the same order as the structure is produced later. First, the base layup is defined using the OSS of the base plate.

Figure : Laminate of the Base Plate

The next plies are added to the stringer.

Figure : Laminate of the Base Plate and Stringer

It is important to define the base plate and stringer laminate before the bonding plies are defined because the order is responsible for the final offset. As shown in Figure : First Bonding Laminate, the bonding layers are applied to the top of the base plate and onto the plies of the stringer.

Figure : First Bonding Laminate

On the other side, the second bonding laminate is offset to the top (base plate) and to the left (stringer).

Figure : Second Bonding Laminate

Cover plies complete the layup definition of the T-joint. Figure : Cover Plies shows that ACP can also handle drop-offs.

Figure : Cover Plies

Release 18.2 - © ANSYS, Inc. All rights reserved.