The linear static orthotropic composite clamped cylinder test considers a cylinder clamped at both ends subject to internal pressure. A cylinder of length a = 20, radius R = 20 and total laminate thickness of h = 1 is subject to a uniform internal pressure of p_0 = (6410/π) [1]. The system is setup as follows:

Problem definition [1]

The laminate is considered in both single and double ply arrangements, with the lamina properties defined as:

• E_1 = 7.5E6,
• E_2 = 2E6
• G_12 = 1.25E6
• G_13 = G_23 = 0.625E6
• ν_12 = 0.25

Due to symmetry only half the cylinder was modeled, while the mesh was refined under the constraint of 'circumferential divisions = 1.5(axial divisions)'.

The key quantity of interest is the maximum radial displacement of the cylinder, with the reference solution taken from Reference [1].

The following displacement contour of the Kratos thin quad element (mesh = 864 elements) with a 2-ply layup is provided for context.

Composite clamped cylinder results: displacement contour of Kratos thin quad element (2 ply layup)

The results of the test for the thin quad and thick triangle Kratos shell elements with a single ply layup are presented below.

Composite clamped cylinder results: single ply layup

The results of the test for the thin quad and thick triangle Kratos shell elements with a double ply layup are presented below.

Composite clamped cylinder results: double ply layup

Both graphs above indicate the thick triangular and thin quadrilateral Kratos shell elements agree with the reference solutions.

1. Junuthula Narasimha Reddy. Mechanics of laminated composite plates and shells: theory and analysis. CRC press, 2004.