1. Redundancy rule

Repeatedly set up multiple components with the same function, sub-function redundancy and principle redundancy;

1) Functional redundancy: backup with the same principle and function;

Functional redundancy is aimed at the failure of the component itself rather than external environmental factors;

2) Principle redundancy: Components with the same function but different principles are mutually backup.

The principle of redundancy adopts different principle devices, such as the monitoring of boiler safety valves, and sensors with different principles such as electricity, light, and heat can be used to prevent two devices from failing at the same time under a certain failure factor.

2. Zero flow criterion

When an external component is required to perform a certain function, let it not rely on or rely as little as possible on external conditions, so as to reduce the external factors that may hinder its performance.

3. Principles of reliable working principle

1) Machinery is superior to electrical, electromagnetic, and hydraulic systems, and its working performance is more reliable;

2) The shape connection method is more reliable than the force connection method. It is difficult for external factors to change the geometric shape of the mechanical component, but it is easy to change the force state.

4. Margin criteria

1) The safety factor method usually increases the size of the component. Many factors in engineering do not have an absolute value, but a distribution range. The margin design is the fundamental solution to the problem.

2) For problems caused by material characteristics such as fracture damage, thermal stress damage, etc., the design of strengthening margins on the size of the component is invalid

5. Safety valve guidelines

  Deliberately place a weak spot, lose the soldier to protect the handsome

  Safety valve, fuse

6. Simple guidelines

1) The minimum quantity, the simplest shape, the minimum process steps, the simplest processing and assembly process, the most common materials, the simplest tools, the simplest disassembly steps...

2) Set quantitative evaluation indicators based on the characteristics of parts.