Separation Bolts | Sep Bolts

Pressure amplified hydrodynamic separation bolt

Industry-specific high energy ~ designed to exceed your mission-critical standards.

Separation bolts or studs are designed for missile, spacecraft and marine applications where rapid structure separation is demanded. Pressure actuated, ridge cut, piston actuated and hydrodynamic (pressure amplified) pyrotechnic explosive bolts are available in a wide range of sizes, configurations and tensile capacities from as little as 200 pounds to as much as 1,000,000 pounds). Our experts are here to support you in meeting your structural loading, envelope and environmental requirements and guide you on ways to mitigate shrapnel and products of combustion.

Interested in our Explosive Bolts?

Industry-specific high energy. Designed to exceed your mission-critical standards.We would love to hear about your program and how we may help.

How An Separation Bolt Works

Separation bolts utilize a pyrotechnic pressure driven piston, internal to the bolt. In piston actuated bolts, the piston travels down the internal counterbore striking the bolt at its break plane effectively pushing the bolt apart. In the case of the hydrodynamic bolt, the piston impacts a hydraulic medium used
to amplify the force to effectively pull the bolt apart.

With separation bolts, more space is required allowing for the internal piston in the head of the bolt. Hydrodynamic bolts are used where any large structural loading is required such as separation of the solid rocket boosters from the Shuttle and SLS main tank.

Piston Actuated bolts have larger space requirements with the combustion products contained within the design and there is no bolt expansion.

Hydrodynamic is the most complex of all our bolt designs. The combustion products are contained and there is no bolt expansion. These are high tensile bolts.

In both designs, the combustion products are contained behind the piston.

Separation Bolts

A pressure driven internal piston acting on a designed break location. Provides for containment of combustion products.

Piston Actuated Pyrotechnic Bolts

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provide for full containment of products of combustion and for force amplification to permit severance of larger bolts. An explosively driven piston of large surface area impacts a hydraulic medium which fails the bolt due to combined hoop and shear stresses.

► Piston Actuated Bolt: the force of a pressure driven piston exceeds strength at break plane

 

Hydrodynamic separation bolt

Hydrodynamic Separation Bolt

Hydrodynamic (Pressure Amplified) Pyro Bolts provide for containment of combustion and for amplification to permit severance of larger bolts. An explosively driven piston of large surface area impacts a hydraulic medium which fails the bolt due to combined hoop and shear stresses.

► Hydrodynamic Bolt: the force of pressure driven piston impacts a hydraulic medium used for force amplification to exceed the strength at the break plane

Applications

Pyrotechnic Explosive Bolt designs are qualified and used for stage separation and release device for missile applications including Standard Missile 3, Range Extending Munitions Aero Packages, Solid Rocket Booster and main tank separation for the NASA shuttle, parachute deployment and mechanism release for weapon system.

Below we have some example applications utilizing the two different explosive bolt types. The loads shown are the proof load requirements and the design margins are typically 1.25x to 2x.

Separation Bolts – Piston Actuated
One Piston actuated bolt Releases the spacecraft from the upper stage.

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And another, a 3-bolt bolt system used to release the flight recorder.

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Hydrodynamic Bolts
These hydrodynamic bolts released the Solid Rocket Boosters from the shuttle and will be releasing them from the NASA’s SLS. Note the proof load strength of these bolts.

In designing new systems, typically the first question we are asked is, “What size bolts do you have?” Although we have many sizes of bolts, each bolt is designed for a specific application and tested to their unique shock, vibration, and temperature conditions. So, each bolt design must be reviewed and tailored against its intended application.

Shuttle solid rocket booster release

Shuttle Solid Rocket Booster Release


Srb forward release 3. 475" 217,500 lb & srb aft release 3x 4. 75" 393,000 lb

SRB FORWARD RELEASE 3.475″ 217,500 lb & SRB AFT RELEASE 3x 4.75″ 393,000 lb

Functions

Our pyrotechnic bolt functions include, but are not limited to, clamp release mechanisms, bulkhead and component release systems, rocket and missile stage separation, flight termination, along with jettison applications such as consumed or damaged structures, solid rocket booster (SRB) and satellite release.

Performance

  • Input Stimulus, Typical
    3.5 amp (when electrically initiated)
    TLX or SMDC input
    4.5 AMP/4.1 millisecond
  • Tensile Strength
    Up to 550,000 lbf
  • Operating Temperature
    Designs as low as -65 °F and up to +270 °F
  • Separation Time, Typical
    <10 milliseconds after application of All-Fire input stimulus
    <5 milliseconds at greater currents
  • Applicable Specifications
    Qualified for:

    • MIL-DTL-23659 Appendix A
    • Mil-C-83124
    • NASA NHB5300.4(1C)
    • Mil-STD-1512
  • Hermesticity (pre-function)
    Designs that comply with 1 x 10-6 cc He/sec at 1 atm

Envelope/Interface Design

Explosive bolt sizes and configurations can be tailored to meet structural loading, envelope and environmental conditions requirements for specific applications.
Explosive bolt technical

Energy Inputs

Please view our Explosive Bolts Energy Inputs article the applicable information is the same.

Redundancy

Please view our Explosive Bolts Redundancy article the applicable information is the same.

Questions to Consider

In designing new systems, typically the first question we are asked is, “What size bolts do you have?” Although we have many sizes of bolts, each bolt is designed for a specific application and tested to their unique shock, vibration, and temperature conditions. So, each bolt design must be reviewed and tailored against its intended application.

To support mission-critical efforts requiring a rapid separation system via explosive or separation bolts, below are some typical questions we ask in order to ascertain the best possible solution.

  • Application – what are you trying to accomplish?
  • What are your tensile/shear and torque loads?
  • What are your space constraints?
  • Is containment required?
  • Redundancy requirements?
  • Input power requirements – electrical, ETL, mechanical?
  • Environmental requirements?
  • Qualification requirements?
  • Military or other requirements?