TourTourFailure of waterway lock gate could be prevented by FMEA
Failure Mode and Effect Analysis (FMEA) is a procedure to identify all possible failure modes of components and their impact on the functioning of the system. The rating is based on the probability of the failure occurrence, the severity of its effects and its detectability. Potential failures with high rating represent the greatest risk and should be eliminated. FMEA is a key tool in quality improvement, the procedure is simple without statistics. The key question in FMEA is: "How can the system fail?"

A new lock gate carried on wheels rolling on rails failed after two years of service. Inspection leads to severe wear of the wheel bearings. Some of the bearing bushes where completely worn through and the shaft was subsequently wearing the metal housing. Simple calculations show that the specific wear rate of the bearings was not higher than could be expected and thus predicted. If an FMEA was conducted this possible failure mode was rated with a high Risk Priority Number and corrective action was taken in design stage.
 



 
 Diameter shaft D   10-3 m
 Bearing length L   10-3 m
 Bearing load F   103 N
 Wear depth d   10-3 m
 Sliding distance s   103 m
 
 Average contact pressure F/(LD)   MPa
 Wear volume V   10-6 m3
 Specific wear rate k   10-15 m2/N
The wear volume V in this calculator is approached by V=dLD which is the case when assuming a wear depth large compared to the radial clearance. For more wear calculators select the item "wear rate" on the home page.  
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