Could somebody please tell me on how to consider flexible hose in the stress calculation? I am stressing a long loading line and the client does not permit the use of expansion loop neither expansion joint. Client specifies flexible metallic hose (say 3m for 10” line) as a way of absorbing thermal growth of piping. The problem is that vendor could not provide the spring rates I need to get through in my calculation. For the time being what I did was I picked up some values from expansion joints vendor catalogue just to have a rough estimate but I am uncertain with the results especially for anchor loads. Am I on the right track? I think that if I use flexible hose the thermal loads could be smaller at least.

Please enlighten me on this matter.

TY.

Flexible hose cannot transmit forces/moments. To make things simple you can consider a discontinuity in the Piping at that location.


Anindya Bhattacharya

Stress Analyst

Bechtel Corporation

Discussion on the topic of flexible hose can be found in this forum using the [Search] button at the top-right of this page. This action will suggest the following threads:

<table border="0">
<tr><td> Modelling Flex Hose with offsets </td><td> </td><td> January 30, 2003</td></tr>
<tr><td> Metal Flex - Hoses </td><td> </td><td>January 28, 2003</td></tr>
<tr><td> Modeling flexible hoses </td><td> </td><td>October 10, 2000</td></tr>
</table>

Thanks guys. It is now clear to me that the behavior of flex hose can't be considered in the program. Here's a follow-up question, would there be any pressure thrust force?

Thanks again.

The amount of force/moment transmitted by a member depends on its relative stiffness in the system. The hose because of its inherent flexibility is as good as a non force transmitting memeber and that includes the pressure thrust also.

Pressure thrust develops due to change in direction of flow . A hypothetical straight pipe with both ends open cannot have pressure thrust. Hence your system does have pressure thrust but it cannot be transmitted through the hose and accordingly the stiffer members take them.

A. Bhattacharya

Stress analyst

Bechtel Corporation