1、Lessons Learned Entry: 0341Lesson Info:a71 Lesson Number: 0341a71 Lesson Date: 1994-08-03a71 Submitting Organization: MSFCa71 Submitted by: Billy ColeSubject: Hydro-Dynamic Vibration in the “Hot Dog“ Area on the Top of the Main Combustion Chamber of the SSME Caused Fractures Description of Driving E
2、vent: Oscillations at the inlet tee in the LOX dome of the main combustion chamber were being caused by the LOX Flowing over the two vane splitter. The vibrations were causing the vanes to crack.Lesson(s) Learned: Though it is known that two types of structural elastic flow interaction is possible,
3、1) vortex shedding and 2) flutter-type instability, not enough effort was spent to understand these interactions at specific locations.Reference(s): NASA technical paper 3213, dated March 1994, titled “The Role of Failure/Problems in Engineering: A Commentary on Failure Experienced-Lessons Learned“,
4、 by R.S. Ryan.Recommendation(s): To fix the high-amplitude and high frequency oscillations at the flow splitting vanes, the vanes leading edges were tapered. Later a design change was to use forging instead of casting, changing material density and increasing damping.Evidence of Recurrence Control E
5、ffectiveness: No high or low amplitude vibrations now measured in this area.Documents Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Hardwarea71 Parts Materials & ProcessesAdditional Info: Approval Info: a71 Approval Date: 1994-08-17a71 Approval Name: Steve Androlakea71 Approval Organization: QSa71 Approval Phone Number: 202-358-0584Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
