Local vibration damping for gas turbine engine housing
A gas turbine engine includes a compressor section, a combustor and a turbine section. At least one casing surrounds at least one of the compressor and turbine section. The at least one casing is formed of sheet metal. The at least one casing has at least one potential peak displacement point due to vibration across a speed range of the one of the compressor and turbine section. A damper is placed on the casing at the at least one potential peak displacement point. The damper has one end fixed to the casing, and a second end not fixed to the casing and the second end provides an interference fit such that the second end cannot move to a relaxed position of the second end due to the wall of the casing. A method is also disclosed.
1. A method of providing a casing for a gas turbine engine comprising the steps of:
1) modeling a casing design for the casing to be formed of sheet metal;
2) determining peak displacement points based upon the modeling of step 1); and
3) providing a damper at at least one of the peak displacement points, the damper having one end fixed to a wall of the casing and a second end which is not fixed to the wall of the casing and having a relaxed position that it cannot reach due to the wall of the casing.
2. The method as set forth in claim 1 , wherein there are a plurality of the peak displacement points at distinct locations and the damper is one of a plurality of dampers.
3. The method as set forth in claim 1 , wherein the one end is fixed to an outer surface of the casing and the second end of the damper is held at a greater outer diameter than the relaxed position due to the outer surface of the casing.
4. The method as set forth in claim 1 , wherein the one end is fixed to an inner surface of the casing and the second end of the damper is held at a smaller outer diameter than the relaxed position due to the inner surface of the casing.
5. The method as set forth in claim 1 , wherein the damper has the one end fixed to a flange on the casing.
6. The method as set forth in claim 1 , wherein there is a cutout through the wall of the casing and the at least one peak displacement point is adjacent the cutout.
7. The method as set forth in claim 6 , wherein the casing has a conical section and a smaller diameter cylindrical portion.
8. The method as set forth in claim 7 , wherein the cutout is in the conical portion.
9. The method as set forth in claim 1 , wherein the damper is formed of sheet metal.
10. The method as set forth in claim 1 , wherein the damper has a bowed portion between the one end and the second end.