CIVE 4311 Design Hazards need to be anticipated. Failure is part of engineering. If doing innovative work, failure is expected. Studying failure produces knowledge for better work in the future.

CIVE 4311 Design Hazards Hazards are things that can be anticipated and then measures implemented to reduce the hazard.

CIVE 4311 Design Hazard Examples: Entrapment Contact (thermal, electrical, chemical) Impact Ejection Entanglement Noise, vibration

CIVE 4311 Design Hazard Mitigation: Review existing standards Identify known hazards Identify unknown hazards “booby traps” Determine characteristics Eliminate or minimize hazards Training Protective Equipment Automated operation

CIVE 4311 Design Identify Hazards Fault tree diagrams Failure mode and effect analysis Fish bone diagrams Statistical methods Severity-Frequency-Peril Dose-response

CIVE 4311 Design Mitigate Hazards Reduce exposure protective barriers limited access Redundancy Warnings (visual, audible) SIGNAL WORD NATURE OF HAZARD POSSIBLE DAMAGE INSTRUCTIONS

CIVE 4311 Design Warnings (Example) DANGER HIGH VOLTAGE CAN KILL STAY AWAY

CIVE 4311 Design Failure Expect the unexpected Respond to warning signals Focus on local and global aspects of design

CIVE 4311 Design Failure Engineering designs fail when they do not perform their intended function. Failure may be temporary or permanent. Failure may result in consequences ranging from trivial to lethal. Should be avoided if possible. All human-made things will eventually wear out, in the context of engineering failure we mean “unexpected failure”

CIVE 4311 Design All human-made things will eventually wear out, in the context of engineering failure we mean “unexpected failure” Design life; how long will the engineered system perform. Duty life/cycle; how long we will allow the system to remain in service. Aircraft are good example, they are made of alloys that have a finite lifetime under cyclic loading and will break if left in service too long.

CIVE 4311 Design Failure Levels Physical flaws Errors in Process Errors in Perspective/Attitude

CIVE 4311 Design Failure Levels Physical flaws Overloading Fatigue Corrosion Insulation deterioration over time (electrical faults). Material choices Inspections

CIVE 4311 Design Failure Levels Errors in process Omission Forgot to do something necessary Forgot to make control systems make sense to actual operators. Commission Do something unnecessary of out of sequence. Do something wrong (that should not be done). Training Simulations Testing Inspections

CIVE 4311 Design Failure Levels Errors in attitude/perspective Arrogance Indifference Selfishness (individual and corporate) Poor communication Misunderstanding of different cultures Choose excellent people! Self-select away from project if they are not committed Education Ethics Need to apply all communication avenues.

CIVE 4311 Design Failure Levels Physical flaws Diligence and attention to detail (engineering) Errors in process Errors in attitude Character (non-engineering)