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Topics for MACE 61054 Explosion Engineering
Topic: Physics of Explosions
Physics of Explosions – part I
Physics of Explosions – part II
Spalling and Fragmentation –I
Spalling and Fragmentation –II
Topic: High Energy Rate Processes
Energy Related Materials
Explosive Welding
Topic: Underwater Explosion
Underwater Explosion -part I
Underwater Explosion -part II
Tutorial questions
Tutorial solutions
Suggested topics for Explosion Engineering Projects
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Microstructure of a solid propellant
SEM image showing fracture surface of a solid propellant.
Reference: Ide KM, Ho SY, Williams DRG (1999) Fracture behaviour of accelerated aged solid rocket propellants. J Mater Sci 34:4209-4218.
A solid propellant consists of ammonium perchlorate (AP) particles with two size ranges (coarse and fine), embedded in HTPB binder.
In reply to Microstructure of a solid propellant by Henry Tan
What is a plastic bonded explosive?
What is a plastic bonded explosive?
In reply to Microstructure of a solid propellant by Henry Tan
Why plastic bonded explosive?
Why plastic bonded explosive?
Void collapse and jet formation
From Prof. Ko van der Weele
A steel ball dropped onto loose, very fine sand creates an impressive jet: Upon impact, sand is blown away in all directions, forming a crown. The ball dives deep into the soft sand, creating a void (like a mine shaft) that immediately collapses again: the "hydrostatic" pressure focuses upon the axis of impact and pushes the sand straight up into the air. (from van der Weele's research website)
In reply to Void collapse and jet formation by Henry Tan
Leaping Shampoo phenomenon
Something relate to a Leaping Shampoo phenomenon?
http://imechanica.org/node/1265
In reply to Void collapse and jet formation by Henry Tan
void collapse in energetic materials
How may this relate to the void collapse in energetic materials, such as solid propellants and explosives, which is one of the major mechanism for the formation of hot spots.
In reply to void collapse in energetic materials by Henry Tan
What are hot spots in explosives?
What are hot spots in explosives?
Interface debonding
From Rae PJ, Goldrein HT, Palmer SJP, Field JE, Lewis AL (2002) Quasi-static studies of the deformation and failure of beta-HMX based polymer bonded explosives. Proc R Soc Lond A458:743–762.
Optical micrograph of the post failure route in a high explosive suggests that macroscopic crack propagation is mainly along interfaces.
In reply to Interface debonding by Henry Tan
quasi-static
While high speed explosion are typical for the behaviour of explosives, why study quasi-static processes?
solid rocket
A solid rocket or a solid-fuel rocket is a rocket with a motor that uses solid propellants (fuel/oxidizer).
In reply to solid rocket by Henry Tan
liquid rocket
why not use liquid rocket as a lunching vehicle?
In reply to solid rocket by Henry Tan
solid rocket motor
A simple solid rocket motor consists of a casing, nozzle, grain (propellant charge), and igniter.
In reply to solid rocket motor by Henry Tan
Combustion surface
metal foams
A metal foam is a cellular structure consisting of a solid metal - frequently aluminum - containing a large volume fraction of gas-filled pores.
A large-cell closed-cell aluminium foam produced from molten aluminium by the Shinko Wire Company (sold under the trade name Alporas).
An open-cell aluminium foam produced by ERG Aerospace
Solid propellant combustion
From Prof. Quinn Brewster, University of Illinois at Urbana-Champaign
Video A
http://www.mechse.uiuc.edu/content/directory/faculty/profile_video.php?slide_id=14
Video B
http://www.mechse.uiuc.edu/content/directory/faculty/profile_video.php?slide_id=15
In reply to Solid propellant combustion by Henry Tan
Thank you Dr.Tan for attaching these videos
Explosion Engineering, Manchester university
Firas Al-matook
In reply to Thank you Dr.Tan for attaching these videos by Firas
enrich the classroom lecturing
Thanks. I will put more things as supplments to the classroom lecturing.
intellectual property laws
I put a lot of links to the internet figures, and the images show automatically. I do not want the pictures be treated as if they are generated by me. But, am I breaking any intellectual property laws by providing these links?
Features of Explosive Welding
I think the main feature of exlplosive welding is the less time required for the process .If we have a large workpiece,i think using this we can weld it faster than any other welding technology.
In reply to Features of Explosive Welding by SibsonDalgo
Other welding technologies
Other welding technologies can be found here.
In reply to Other welding technologies by Henry Tan
I think its worth mentioning
I think its worth mentioning the difference b/w cold welding and hot welding.
In reply to I think its worth mentioning by SibsonDalgo
cold and hot welding
can you explain to us cold and hot welding?
In reply to cold and hot welding by Henry Tan
Difference ,Hot and cold welding
I am sure that everyone is familiar with hot welding, which
is infact the ordinary welding where two metal forms a weld pool and on cooling
they will attach together. But in cold welding the melting of the two metals won’t
happen this has got lot of advantages because we can join materials which are
not weldable for eg, Powder metallurgy and ofcourse Explosive welding.
In reply to Difference ,Hot and cold welding by SibsonDalgo
weldablility
why some metals are not weldable, some are?
In reply to Features of Explosive Welding by SibsonDalgo
Detonation velocity
Detonation velocity of commonly used explosives can be found from here
In reply to Features of Explosive Welding by SibsonDalgo
Dear Sibson, good point
Dear Sibson, good point.
Henry.
In reply to Features of Explosive Welding by SibsonDalgo
references to justify your point
can you give some references to justify your point?
Explosion Welding - surface finish
With regards to a question on the surface finish of explosion welding in the last lecture - it seems that some slight deformation must occur as the two layers are generally flattened after they have been explosively welded together. See www.dynamicmaterials.com/divisions/clad%20Metal%20Group/Explosion%20Wel…
The page also has a video of the explosion welding (although you cant see much)
In reply to Explosion Welding - surface finish by John Kelly
nice video
I watched the video, it is very interesting. John, thank you for providing the link.
Explosive Welding -Standoff Distance
Is Stand-Off Distance a pure function of the Jeting Angle??ie , While choosing the stand-of distance do we have to consider any other things other than jetting angle?
In reply to Explosive Welding -Standoff Distance by SibsonDalgo
yield of the explosive
Does it also depend on the yield of the
explosive?
In reply to yield of the explosive by Henry Tan
Can u make it clear? Wat is
Can u make it clear? Wat is yield of the explosive and how it deprnds on the stand-off Distance
In reply to Can u make it clear? Wat is by SibsonDalgo
Professor Stephen Reid
Stephen Reid, who used to be a Professor in this school (UMIST), did a lot of original work on explosive welding in 1970s. Maybe you can read some of his papers, and get deeper understanding of the subject.
Dear Dr. Tan
Firas Al-matook
how can we classified the type of underwater explosion if d/W1/3 is more than 1 and less than 16 because if it less than one is shallow and if it more than 16 classified as deep underwater explsosion.
In reply to Dear Dr. Tan by Firas
underwater explosion
<1 (shallow) and > 16 (deep) are two extreme cases for underwater explosion. For those two cases, mathematically the controlling equations can be simplified, and physically they each share common behaviours.
For the cases in between, the behaviours are complicated. Taking an example for bubble dynamics:
(1) for deep underwater explosion, the interactions between the bubble and the water surface can be ignored;
(2) for shallow underwater explosion, bubble burst into the air quickly.
(3) for >1 and < 16 underwater explosion, the interactions between bubble and the water surface need to be accounted for.
Hi Dr.
Firas Al-matook
am hazitated to do flying impact analysis ( shock wave and Rankine-Hugoniot equations) on my dissertation topic despite of it is about Aluminium aircraft impacting a concrete rigid barrier with impact velocity. the reason why am hazitated that am assumed the density after impact remains the same as before during my experimenta analysis, i.e. no pentration or structure deformation though Hugoniot considers two densities.
plz Dr, if you can give me an advice to solve this issue, I would like to do it becous in real life the impact of aircraft with a rigid structure as what happened in WTC sustains obviously two different densities.
many regards
FIRAS Al-MATOOK
MED
Manchester University