1.8.5 Including deformable element types in a rigid body

Product: ABAQUS/Explicit

Elements tested

C3D8R B31 S4R T3D2 F3D4

Feature tested

Defining deformable elements as part of a rigid body.

Problem description

This example, which is similar to “Tennis racket and ball,” Section 2.1.5 of the ABAQUS Example Problems Manual, simulates the oblique impact of a tennis racket onto a stationary ball. The frame of the tennis racket is assumed to be rigid and is modeled using solid and structural elements of type C3D8R, B31, and S4R as part of a rigid body by referencing them on the *RIGID BODY option.

The strings on the tennis racket are modeled using T3D2 truss elements. The details of the material model used for the strings can be found in “Tennis racket and ball,” Section 2.1.5 of the ABAQUS Example Problems Manual. The strings are initially in tension, which is specified using the *INITIAL CONDITIONS option. The tennis ball is modeled as a sphere using S4R elements and is assumed to be made of rubber. The tennis ball is subjected to an initial internal pressure using hydrostatic fluid elements of type F3D4 to model the gas in the ball. A coefficient of friction is specified between the ball and the strings. In this example the ball is initially at rest, and the racket impacts the ball at 6.706 m/sec (264 in/sec) at an angle of 15°. The density of the elements representing the racket is chosen such that the mass of the racket is nearly 10 times that of the ball.

The complete model is shown in Figure 1.8.5–1.

Results and discussion

Figure 1.8.5–1 shows the position of the ball with respect to the strings in the undeformed configuration. The deformed shapes at different stages of the analysis are shown in Figure 1.8.5–2 through Figure 1.8.5–4. The tennis racket frame can be seen to be moving as a rigid body, rotating slightly due to the distance between the point of impact and the racket center of mass. A deformation magnification factor of two has been used in plotting the figures.