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Video 01 - FAQ Explanatory Video

Figure 01 - Example model of an inclined container

Figure 02 - Non-aligned local coordinate systems on the vessel

Figure 03 - Alignment of the local coordinate systems with a container

Figure 04 - Aligned local surface coordinate systems on a container

Figure 05 - Axial and circumferential membrane stresses on a container

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New

FAQ 004257 EN

2 December 2019

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How can I read the axial and circumferential stress for a circular container?

Answer

Since surfaces only have the directions x- and y- in the plane, it is necessary to define which should be the circumferential and the axial stress. In the following example, sigma_x should be the axial stress and sigma_y the circumferential stress.

The example consists of an inclined circular container (Figure 01). After modeling, the program tries to align the local axis systems with the global axis system (Figure 02). In the present case, however, the x-axis should run along the container for all surfaces. This orientation can be achieved as follows.

First, the z-axis of all surfaces must point inwards or outwards. In the example, the outward direction has been selected. If this is not the case for a surface, you can right-click the surface and use the function "Reverse Local Axis System" to move the z-axis to the other surface side. Then, select all surfaces and select the Axes tab in the surface dialog box. Figure 03 shows the dialog box. In this case, one of the axially extending boundary lines has been selected for the orientation. Figure 04 shows the now aligned local axis systems. All x-axes are axial and all y-axes are circumferential.

Figure 05 shows the results of the membrane stresses axial (sigma-x, m) and over the circumference (sigma-y, m).