OS-V: 0750 Radial Stretching of a Cylinder

Illustrates the use of asymmetrical elements (CTAXI) under uniform radial displacement in OptiStruct.

Model Files

Before you begin, copy the file(s) used in this problem to your working directory.

Benchmark Model

Figure 1. Cylinder Subjected to Uniform Radial Displacement

The inner and outer radii of the cylinder are 4.0 and 6.0 respectively. A mesh of 20*20 elements is used to model the axisymmetric model with first and second order CTAXI elements. The cylinder base is constrained in the axial direction, inner edge is constrained in the radial direction and a radial displacement is enforced using SPCD along the outer edge of the cylinder.

The material properties are:
Young's Modulus
2 x 1011 Pa
Poisson's Ratio
1,000 kg


Figure 2. Plot of Radial Stress versus Radial Distance for CTAXI Element
The results of both 1st and 2nd order CTAXI elements agree with the analytical solution with radial stress along the radii 4.0-6.0m, reducing (parabolic curve) from 26.3E9 to 21.2E9 Pa.

Figure 3. Plot of Hoop Stress versus Radial Distance for CTAXI Element

Below radius 5m, the results of 2nd order CTAXI elements are an excellent match with analytical solution, and above 5m, the results of 1st order CTAXI elements are a better match to analytical solution.