Machine (physical) fatigue and aging

The fatigue and aging of machinery (things) is a natural phenomenon, and it is the fundamental law of nature that does not depend on human will

Any objective existence in nature has a process of production, development and change, and fatigue and aging are the universal characteristics of this process

Which objects (machines) are fatigued or aged to a certain degree, which will become safety hazards? According to the logical relationship diagram of non-hazard sources, hazard sources, safety hazards and accidents, it can be known that the hazard sources containing energy or the non-hazardous sources that carry energy later The source of danger, fatigue or aging to a certain degree, may become a safety hazard.

The whole thing (machine) or its components and components mostly move under cyclic loading.

Physical factors, chemical factors, biological factors, environmental factors, process factors, and even management factors are the main causes of fatigue and aging of objects (machines) and their components or components

(1) physical factors: temperature, humidity, voltage, electromagnetic, vibration, shock, overload, wear, mechanical damage

(2) chemical factors: oxidation, polymerization or decomposition, corrosion, and other failures

(3) biological factors: microbial attack and decomposition

(4) Environmental factors: photolysis, high temperature aging, low temperature brittle, deterioration of environmental conditions and the like

(5) Process factors: unreasonable design, material wrong way, bad manufacturing process, the installation process is not reliable

(6) Management factors: lack of respect for science, in violation of objective laws, ranked preferably inferior, command and other unplanned blind

The fatigue and aging caused by the above factors may lead to local or overall structural changes, and local or overall defects develop, so that various physical and chemical parameters cannot meet the safety and reliability requirements of the original design

Fatigue and aging are practical problems all the time and everywhere.

The fatigue and aging of objects (machines) are directly related to potential safety hazards and accidents.

Case 1

A R&D personnel made the following reaction in a stainless steel PTFE tank:

Add 1.

Reason analysis: the stainless steel PTFE tank is aging due to long-term high temperature use
.
In addition, the strength of PTFE will be greatly reduced due to high temperature, and the reaction of phosphorus oxychloride and water will produce a large amount of hydrogen chloride gas, which will cause the pressure to rise suddenly at a high temperature of 120 ℃, and finally cause the bottom of the inner tank to rupture, and the reaction liquid Rush out
.
There have been too many such accidents in various units
.

Case 2

A R&D personnel prepared to react.
When the feeding was completed and the power supply was plugged in, the countertop in the fume hood suddenly caught fire
.
The result of the inspection is that the wire of the strong agitator is aging and the exposed metal wire causes a short circuit to cause electric sparks, as shown in Figure 24-62, and ignites the ethanol splashing on the table, as shown in Figure 24-63
.

There are many accidents caused by similar reasons
.
For example, the insulating rubber of the power cord of the agitator on the countertop is corroded by chemical reagents in a fume hood for a long time and falls off.
The internal charged metal wire is exposed to the air, and the spilled organic solvent contacts the charged metal wire to cause burning, as shown in the figure.
Shown in 24-64
.

Figure 24-64 The scene after wire aging, cracking and fire

Pay attention to the use of equipment and equipment: do not let equipment and equipment work fatigued, work with illness, and report for repair in time if equipment is found to be faulty
.
Everything has "spirituality.
" If you treat it well, it will naturally provide you with good help.
If you don't care about it, if you abuse it, it will retaliate against you
.