공업재료는 기하학적으로 응력집중(노치)이 되는 부분이 있다고 가정
국부적인 항복이 응력집중에 의해 발생
국부적 소성항복은 변형을 일으켜 slip boundary를 형성하고 이것들이 유착되어 균열 생성
압축, 인장이 순환될 때 균열은 열고 닫힘을 반복
항복은 순간적으로 멈추고 균열은 다시 날카롭
1. Financial Model
Actual cost of PM
Cost of repair/corrective
maintenance
Cost of replacing
equipment
Expected useful life of
equipment
Effects of PM on expected
useful life
Frequency of required
repairs when equipment is
no maintained
Effect of PM on energy
consumption
2. What they investigate?
14million square feet/119million square feet
Type of equi
3.2. PM(Preventive Maintenance)
3.2.1. What is the PM?
"Preventive Maintenance is a scheduled program of regular inspection, adjustments, lubrication, or replacement of warm or failing parts in order to maintain an asset's function, and efficiency (Ryan Cruzan, 2009)
Preventive Maintenance is the task that we perform to keep buildings in good condition. So Preventive Maintenance includes task
3. Experimental tools
1) Ultrasonic detector
It is widespread use of equipment that used in ultra sonic testing. And it also have lots of control function.
2) probe
A protected face transducer is a single element longitudinal wave contact transducer that can be used with either a delay line, protective membrane, or protective wear cap.
3) couplant A couplantis a material (usually liq