RMQSI Answers ForumCategory: General Questions and CommentsReliability of electric-Bridge- wire detonator
baigamin asked 12 years ago

I want to predict the reliability of explosive bolt based on electric birdge wire
detonator.Can some body suggest me appropriate approach.can I start by considering it eithe a resistor or or heating element?
I will be thankful in this regard.

4 Answers
smorris answered 12 years ago

This is a tough question/problem with no quick and easy answers. Listed below are some thoughts/observations/considerations based on the following two Wikipedia links that provide some background on these devices.

http://en.wikipedia.org/wiki/Explosive_bolt
http://en.wikipedia.org/wiki/Exploding_bridgewire_detonator

Need to consider the material properties of the bolt itself, since the bolts themselves apparently incorporate the pyrotechnic charge, which breaks the bolt into two or more pieces. For example, performing a finite element analysis on the bolt to verify it will “fail” in the proper/expected locations.

An EBW has two main parts; a piece of fine wire which contacts the explosive, and a “strong” source of high-voltage electricity

highkeas answered 12 years ago

I want to predict the reliability of explosive bolt based on electric birdge wire
detonator.Can some body suggest me appropriate approach.can I start by considering it eithe a resistor or or heating element?
I will be thankful in this regard.

There are two main parts to predicting the reliability of an exolosive bolt.

No you can’t consider a detonator as either a resistor or heating element. There is a complex physics involved in designing bridges.
The detonator requires the correct electrical stimulus to fire. Due to the expense of testing large quantities the most efficient method is to use a statistical sensitivity test (such as a Bruceton or Neyer). The detonator manufacturer should be able to supply this info.
Do no

The bolt also requires analysis. Using a stress-strength approach works well. Compare the detonator explosive output to the energy required to fracture the bolt.

To get an accurate reliability requires input from an expert in the design of explosive bolts or similar items.

baigamin answered 12 years ago

Aslam-o-Alaikum
I m considering Voltage source as 100% reliable.
I am facing diffculties in deciding my final approach.
I have Marked the follwing intended milestones.
Explosive bolt is a one shot device that remains most of its life in dormant enviroment.
what should I predict?
1.Its probablity of success
2. misson reliability (mission time 5 ms)
3. Dormant reliabilty(how?)
4. Life? (failure)
Thanks in advance for Suggestions.

smorris answered 12 years ago

Usually, for one-shot devices, you model probability of mission success. There have some studies that have looked at dormant reliability of microelectronics, but I don’t think they cover explosive bolts. However, maybe you can get some ideas from reviewing them.