What is understood as “Corrective Maintenance”?
Corrective Maintenance is understood as the action taken after a failure: Maintenance is carried out after a part has failed.
Important: Parts must be safe to fail (failure is easy do observe, does not harm other components and user is not at risk)
What are advantages and disadvantages of Corrective Maintenance?
As long as possible service life -> Lowest service cost
Very Simple
Low reliability —> Considerable and unplannable system downtime
Safe to fail design must be adhered to
What is understood as “Preventive Maintenance”?
In the case of preventive maintenance, parts are replaced before a failure is expected, no matter the current condition.
What are advantages and disadvantages of Preventive Maintenance?
Near zero downtimes
—> Reduced risk during operation
—> High efficiency of the equipment while in use
Unefficient Maintenance —> Relativly high cost
Relativly high Maintenance time —> Less usage of the equipment
Detailed planing and modelling needed (otherwise unsafe failure or unreasonably high costs)
What is understood as Condition Based Maintenance?
The condition of to be maintained components is monitored, and replacements are carried out accordingly.
What are advantages and disadvantages of Condition Based Maintenance?
More efficient use of resources then with Preventive Maintenance
More efficient use of equipment then with Preventive Maintenance
Condition Montioring is needed.
Unplanned downtimes more likely
What is understood as Predictive Maintenance?
The condition of the system is indirectly assessed via the operating parameters and a system model —> Failure is predicted and maintenance carried out accordingly.
What are the advantages and disadvantages of predictive Maintenance? Derrive the motivation for predictive Maintenance
Most efficient use of the equipment
Most efficient use of resources
No direct condition monitoring necessary —> Standard parts and retrofitting possible
Downtimes can be planned, because State of Health is constantly assesed and failure during planned downtimes is predicted
Good system model necessary
Unplanned downtimes still possible (However this is influenced by the quality of the model)
The Motivation for Predicitve Maintenance derrives from the combination of the ideal use of the given ressources and an efficient use of the system:
How do system models that are used for predictive maintenance differentiate regarding the system knowledge?
If the system behaviour is understood well, an analytical white box model can predict failures. However in real world applications the systme behaviour is not known completly, therefore most often grey box models are used.
If the system behaviour is not udnerstood, self-evolving, data-driven black box models can be used.
How are Condition Monitoring (CM) and Damage Prediciton (DP) differentiated?
(The underlying concepts of Condition based and Predictive Maintenance)
CM gives the current State of Health (SoH). Mostly after a certain point of oberserveability.
DP on the other hand not only gives the current SoH, but also gives a future estimate how the SoH is going to evolve, and can therefore give a Remaining Useful Life (RUL) estimate.
COMPREDICT CardS?
What does the abreviation MTTF stand for?
Mean Time to Failure
What does the abreviation MTBF stand for?
Mean Time Between Failure
What does the abreviation MTTD stand for?
Mean Time to Diagnosis
What does the abreviation MTTR stand for?
Mean Time to Repair
Complete the graphic with the abbreviations MTBF, MTTF, MTTD, MTTR:
Describe the different abbreviations used:
SM: Safety distance
sigma_W: Load capacity
sigma_B: Mean load distribution
s_W: stochastic spread of the load capacity
s_B: stochastic spread load distribution
How can the safety factor be determinend by the Mean load distribution and the load capacity?
With
Zuletzt geändertvor einem Jahr
