Explosive impact factor

[corus]

I'm trying to find the pressure which would cause a vessel to fail from a sudden increase in pressure, say by an explosion. Would an impact factor apply, and what value would be appropriate?

corus

 

[TGS4]

Explosions, or rather "impulsively loaded vessels" are very complex. There is a special working group in the ASME Code Committees that is currently working on rules for this topic.

If I recall correctly, this gets into strain-rate-sensitive deformation - if the strain rate is very high in "tough" materials, then the instantaneous pressure could be higher than the steady-state pressure that would cause a vessel to "fail".

I would check out the ASME PVP Conference papers to see what's been done in the last 5 years. There has been work done by LANL - they were designing pressure vessels to test high explosives.

 

[jte]

In addition to what TGS4 said, if your "sudden increase in pressure" is a deflagration rather than a detonation then VIII-1 Appendix H provides a bit of guidance. It also covers the difference between a deflagration and detonation.

ASME papers are available online. Here's a link to one small subset:

http://www.asmedl.org/dbt/dbt.jsp?KEY=ASMECP&Volume=2008&Issue=48272#MINOR5

jt

 

[LHunter]

You really need to define your explosion. There is explosive modeling software out there but it is difficult to obtain. You need to determine shock pressure & gas pressure. The shock will "reflect" inside the vessel so the impact load will repeat itself. I have used 2x the shock value as a design load in the past but vessel wall thickness must be considered as the load is so fast (applied & gone in the millisecond time frame) that the entire wall thickness may not react to the shock for a thick wall vessel. Look up some of the work Sandia has done in this regard - it used to be widely available.