CES Blast Effects & Damage Assessment 3

Question 1

The Mach stem forms during a surface burst when:

Accepted Answer

The incident and reflected waves merge along the ground surface

Answer

The Mach stem is a near-vertical, reinforced shock front created when the incident wave and the ground-reflected wave coalesce at a specific angle.

Question 2

Cratering from a buried explosive is classified as 'camouflet' when:

Accepted Answer

No surface rupture occurs and only a subsurface cavity is formed

Answer

A camouflet is an underground explosion that creates a subsurface void without breaking the surface, leaving no visible crater.

Question 3

Which metric is used to compare the brisance of different explosives?

Accepted Answer

Plate dent test (copper crusher) value

Answer

The plate dent (or copper crusher) test measures the depth of indentation caused by detonation, providing a comparative brisance index.

Question 4

In blast damage assessment of reinforced concrete, spalling on the distal face (far side from blast) indicates:

Accepted Answer

Reflected tensile stress exceeding the concrete's tensile strength

Answer

Spalling on the far face occurs when the compressive wave reflects as a tensile wave, and concrete — weak in tension — fractures and ejects material.

Question 5

The TNT equivalence factor for a non-TNT explosive is determined by comparing:

Accepted Answer

Heat of explosion values or peak overpressure at a reference distance

Answer

TNT equivalence is derived from either thermochemical heat of explosion ratios or empirical overpressure measurements referenced to TNT at the same standoff.

(CES) Certified Explosives Specialist Practice Test

(CES) Certified Explosives Specialist Practice Test

CES Blast Effects & Damage Assessment 3