Dynamic pipe strain is much more difficult to check since it occurs while the system is in operation. It is commonly due to thermal expansion of the piping, the weight of the system fluid or both of these along with inadequate piping or piping support. Dynamic pipe strain is most often detected by using a measurement device to check for differences in machine movement between static and dynamic conditions.
Pipe strain causes distortion of the machine frame. As the frame or casing is distorted, so are the bearing housings, the shaft and other components. These problems can lead to excessive bearing temperatures. The bearing problems can be detected through vibration analysis, which will have bearing fault frequencies as the dominant peaks. Packing and mechanical seal performance will also be affected by pipe strain because of the additional forces caused by the distortion to the bearing bore. Anything that leads to shaft deflection or reduced bearing clearances can quickly lead to catastrophic failure, particularly of bearings and seals.