GJB 373B-2019 in English

Background of Standard Revision and Technological Evolution

As the top-level standard for the safety design of military fuzes in my country, GJB373B-2019 inherits the technical accumulation of the first edition in 1987 and the revised edition in 1997, and mainly responds to the following technical development needs:

Core safety design elements

4.2.2 Redundant insurance device design

The standard requires that the fuze must be equipped with at least two independent insurance devices. Typical implementation plans include:

• Mechanical rotor + environmental sensor dual insurance structure
• Dynamic energy switch and electromagnetic lock composite insurance
• Heterogeneous combination of centrifugal insurance and air pressure sensor

The verification of independence needs to be proved by fault tree analysis (FTA) that the probability of common cause failure is ≤1×10^-6.

5.2.4 Non-isolated explosion sequence control

For fuzes using permitted explosives such as Poly-Ao-9, the following conditions must be met:

Key technical innovations

4.9 Logic device safety control

For programmable devices such as FPGA, the standard clearly states:

Implementation suggestions and precautions

1. Design verification:FMEA analysis is required to cover all credible failure modes
2. Production control:An independent quality traceability system should be established for key parts
3. Electromagnetic compatibility:RE102/CS115 test is carried out according to GJB151B-2013
4. Software security:Follow the GJB2786 development process, and the code needs MC/DC test

5.6 Safety margin design of electric explosive device

Main points for verification of no-fire threshold (MNFS):

• Test sample size ≥ 50 rounds, confidence level 95%
• Margin factor ≥ 1.5 times the maximum interference level
• Need to simulate the worst case of power supply transient (PST)