I have a gentle question: Why is it said that simulating the device outlet as ANC is a conservative approach?
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Although simulating the equipment outlet as ANC ignores the flexibility of the outlet, it also overlooks the forces exerted on the pipeline due to factors such as foundation settlement of the equipment and thermal expansion. Why do people say that simulating the equipment outlet as ANC is a conservative approach? I’m a bit confused; am I too stupid? I hope someone knowledgeable can offer some guidance
The settlement of the equipment foundation can be determined by the initial displacement； The thermal expansion factor is caused by temperature loads, and this is also taken into consideration ； These factors cannot be ignored during calculations. By simulating the device outlet as an ANC, it is assumed that the device outlet is a rigid body with infinite stiffness. This will result in the thrust or thrust moment at the pipe outlet being greater than the actual value. If you have studied beam theory in engineering mechanics, you will understand that when the ends of a beam are fixedly supported, this limits the three displacements and three rotational degrees of freedom at those ends; as a result, the forces and moments acting on the beam ends are quite large. If the ends of the beam are simply supported, only vertical displacement is restricted, and the forces and moments at the beam ends come out to be different values, which are relatively smaller. These two types of support represent the most common forms of restraint, and they also constitute the two extreme cases for the constraints at the ends of beam elements. In practice, the constraints at the ends of beams are usually somewhere between these two extremes. The reason for this transition between the two states is the slight deformation near the device’s outlet, which causes the device’s outlet opening to no longer have infinite stiffness. Therefore, if ANC constraints are used to define the pipe openings, the calculated forces and moments on those openings will be higher. If the equipment remains safe under such conditions, then the actual operating conditions will also remain within the safe range.
This post was last edited by cacusys on 2010-11-29 at 16:15; you can refer to Esfer’s official reference materials
Simulating the nozzle as ANC is equivalent to ignoring its flexibility; this results in a higher thrust at the nozzle. However, it is said that generally the nozzle is first simulated as ANC, and only if that approach doesn’t work well is it simulated as a flexible nozzle