Why do end caps such as elliptical and butterfly shapes all have straight edges?
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Why do end caps such as elliptical and butterfly shapes all have straight edges? I hope everyone will engage in more communication and discussion!
Someone has already asked this question; give it a search
I think it’s probably for ease of manufacturing.
First, it is convenient for manufacturing end caps; second, it gives an attractive appearance after being welded to the cylinder body.
Avoid welds in the edge stress areas.
Since the head is a workpiece with a changing shape, stress concentration occurs in the areas where the shape changes; there is also a region where this stress gradually decreases. Residual stress is inevitably present in the welds. To prevent these two types of stress from overlapping, heads are usually provided with straight edges. Conical heads come in versions without straight edges, but there are many restrictions.
The answer for the sixth floor plus the feasibility of production constitutes the complete answer.
Another reason is to facilitate connection with the cylinder, allowing for the easy preparation of grooves for welding.
The main purpose of having straight edges on elliptical and disc-shaped heads is to separate the welding stresses in the cylinder and the head from the boundary stresses at the junction between them, so that they do not overlap. Welding stresses are well-known, so no further explanation is needed. Boundary stress arises because when the head is subjected to internal pressure, the shell deforms and becomes circular, causing contraction at its tangent points and a reduction in diameter; meanwhile, the cylinder’s diameter increases under internal pressure (the opposite occurs under external pressure). During the welding of the equipment, their diameters are the same, but such deformation occurs during operation. The head and the cylinder are not separated (and cannot be separated either), so deformation coordination is required at the tangent points of the head (at the joints where the straight edges meet the elliptical or disc-shaped sections), and this is what leads to the formation of boundary stress.
1. To eliminate stress concentration at the edge of the head 2. To facilitate welding during assembly with the cylinder body
Thank you for the explanation; it was very informative.:handshake
What was said on the 11th floor is concise and fairly accurate!
I agree with what was said on floor 11 too! A very professional response!