A Brief Overview of Linear Explosives

Linear explosives are basically explosive powder or material that's drawn in a continuous metal sheath. Inputs for a detonating material need to be another detonation or high shock. For deflagrating type materials in a metal sheath, it should be a detonation, flame, or heat input. Outputs will be detonation shockwave for Mild Detonation Cord (MDC), Mild Detonating Fuze (MDF), and Linear Shaped Charges (LSC). Rapid Deflagrating Cord (RDC) and Auto-Ignition Material Cord (AIMC) material would have pressure or a flame as outputs.

Basic Types Manufactured

Linear Shaped Charge (LSC) / Flexible Linear Shaped Charge (FLSC):

Linear Shaped Charge (LSC) and Flexible Linear Shaped Charges (FLSC) utilize a function described my the Monroe Effect.

This image shows the Monroe Effect with a target underneath and a piece of linear shape charge. The explosive in the middle and the shaved charge sheath could be silver, copper, lead, tin, or even aluminum. The target is located underneath. A standoff allows the formation of a jet in the center picture. This is going to develop when the explosive material initiates and the inner core (or inner apex) collapses in on itself. The jet, composed of metal flakes and high heat, then hits the target creating a penetration. In some cases, it my only be sized for 70% and a shockwave will induce a fracturization or pulverizing of the target material to break it the rest of the way.

Mild Detonating Cord (MDC) / Mild Detonating Fuze (MDF):

Mild Detonating Cord (MDC) fractures target material with detonation shock wave at the point of intimate contact.

Rapid Deflagration Cord (RDC):

For Rapid Deflagration Cord (RDC), we use an explosive transfer line. Currently, this line can be found in the F-35 Lightening II and the T-7 Red Hawk. RDC has been used in other applications on missiles, including as a small time delay because it's a slower burning material that is well characterized.

Auto-Ignition Material Cord (AIMC):

Auto-Ignition Material Cord (AIMC) is used in our Thermally Initiated Venting Systems on missiles. It will automatically ignite if an unintended heat source is threatening the rocket motor on board a missile.

Features

Common sheaths for linear explosives are copper, tin, aluminum, silver, and lead. Linear cord is measured in grains per foot (one grain is equal to about 0.065 grams of explosive material).

Velocity is used to understand how well the material is performing. The velocity is dependent upon the type of explosive material. For detonating HNS, the velocity is somewhere around 6.500 meters/second, but PBXN-5 can have a velocity as high as 8,300 meters/second. For Rapid Deflagration Cord the velocity is somewhere around 300 meters/second. The differences are there so customers can choose what they want on their system. For example, with a heavy shock it's detrimental that a deflagrating material is used.

For more information on our Linear Explosives, please visit: https://psemc.com/products/linear-explosives/