Subsea Frangibolt

Subsea Frangibolt 2017-10-26T17:20:02+00:00

SEE HOW IT WORKS!

TiNi’s Subsea Frangibolts use a polyurethane outer jacket and sealed cable such that they may be used directly in sea water and at very high pressure. As in space applications, the Frangibolt offers a uniquely simple and effective means to release deployables remotely in hostile environments. Standard size Actuators are available for bolts up to ½” which can support and release loads in excess of 10,000 lbf.

TiNi Subsea FRANGIBOLTs OFFER THE FOLLOWING ADVANTAGES:

NEA (Non-Explosive Actuators)
 – As with all TiNi products, the Frangibolt is non-pyrotechnic and field reset-able with a minimum qualified life of 60 cycles.

Rated to High Pressure – 
The Frangibolt Actuator includes no “open internal volumes” that may be susceptible to external pressure. Furthermore, the TiNi cylinder, Polyurethane jacket, and SubConn Cable are insensitive to the harsh sea and subsea environment.

Easy to Reset & Simple to Use – 
The actuator is reset by the customer in a matter of seconds (i.e. no need to ship back to TiNi). This enables numerous system level testing to be performed prior to flight usage to ensure maximum reliability.

Redundant – 
Each Frangibolt incorporates a redundant heater which is capable of independently functioning the actuator.

Safe to Use and Operate – 
The Frangibolt does not pose any safety concerns to personnel, is low shock, and insensitive to ESD (Electro-Static Discharge).

Cost Efficient – Due to its relative simplicity, TiNi Aerospace is able to provide the Frangibolt at a significantly lower price than comparable devices.

Subsea Frangibolt Options

ACTUATOR FB3U

The FB3U size Frangibolt Actuator is designed to operate with a TiNi supplied #10 size Titanium Fastener (see below). These have a nominal tensile strength of 2,400 lbf (10,676 N) and are recommended for use in bolted joints which require up to 1,400 lbf (6,227 N) of preload. As with all TiNi products, key attributes include:

Features:

  • Non Pyrotechnic and Field Reset-able
  • Redundant Firing Circuit,
  • Maximum Reliability Thru
    • Design Simplicity
    • Pedigree, and
    • Testability

    * TiNi Aerospace must provide the specially notched Titanium fastener. This is largely application dependent and is readily manufactured to customer specification.

Function Time at Various Temperatures

Nominal values for estimation purposes only. Actual function time depends on application (joint) design and circuit used (primary or secondary).

FB3U Details

Specification subject to revision. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

ACTUATOR FB4U

The FB4U size Frangibolt Actuator is designed to operate with a TiNi supplied 1/4” size Titanium Fastener (see below). These have a nominal tensile strength of 5,000 lbf (22,241 N) and are recommended for use in bolted joints which require up to 2,500 lbf (11,120 N) of preload. As with all TiNi products, key attributes include:

Features:

  • Non Pyrotechnic and Field Reset-able
  • Redundant Firing Circuit,
  • Maximum Reliability Thru
    • Design Simplicity
    • Pedigree, and
    • Testability

    * TiNi Aerospace must provide the specially notched Titanium fastener. This is largely application dependent and is readily manufactured to customer specification.

Function Time at Various Temperatures

Nominal values for estimation purposes only. Actual function time depends on application (joint) design and circuit used (primary or secondary).

FB4U Details

Specification subject to revision. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

ACTUATOR FB6U

The FB6U size Frangibolt Actuator is designed to operate with a TiNi supplied 3/8” size Titanium Fastener (see below). These have a nominal tensile strength of 10,000 lbf (44,482 N) and are recommended for use in bolted joints which require up to 6,000 lbf (26,689 N) of preload. As with all TiNi products, key attributes include:

Features:

  • Non Pyrotechnic and Field Reset-able
  • Redundant Firing Circuit,
  • Maximum Reliability Thru
    • Design Simplicity
    • Pedigree, and
    • Testability

    * TiNi Aerospace must provide the specially notched Titanium fastener. This is largely application dependent and is readily manufactured to customer specification.

Function Time at Various Temperatures

Nominal values for estimation purposes only. Actual function time depends on application (joint) design and circuit used (primary or secondary).

FB6U Details

Specification subject to revision. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

Subsea Frangibolt Accessories

FRANGIBOLT RESET TOOLS

All of TiNi Frangibolts are rated to have a minimum life of 60 cycles. For continued testing and preparation for installation, TiNi provides a range of Frangibolt reset tools as shown. These are made up of a high quality hydraulic pump, cylinder and pressure gage designed to generate the force and stroke required to compress the actuator.

Compression of the Frangibolt actuator is a simple 3 step process: First, install the unit in the fixture as shown. Second, pump the handle until the prescribed pressure is reached. Third, release the pressure via the bleed screw and remove the actuator. The whole process may be carried out in less than 30 seconds. Furthermore, the size and weight of the Frangibolt Compression Fixture make it fully portable allowing easy transport.

Reset Tool Details for TiNi Frangibolt Options

Note: All values are approximate and for reference only. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

FASTENERS

The Fasteners used in the Frangibolt release system are an integral part of the mechanism. For all Frangibolt sizes, a significant amount of testing was performed to derive the optimum material, notch profile and notch diameter. These features must remain constant for all applications. The customer typically specifies the Fastener type, grip and thread length as well as the notch location. TiNi Aerospace Fasteners are manufactured per strict tolerances and procedures involving both individual and lot-level testing and inspection.

The picture below illustrates some of the more common Fastener configurations that have been successfully used. Each suits a different type of Frangibolt joint design and lends enormous versatility to this unique product.

*Fasteners are made from 6AL-4V Titanium per AMS 4965 with a minimum tensile strength of 160 Ksi (1104 MPa) Note: All values are approximate and for reference only. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

Fastener Examples

WASHERS

The Washers used in the Frangibolt assembly are an important part of the mechanism. They serve the following critical functions:

  • They distribute the relatively high recovery stress generated by the Nitinol cylinder during actuation, on a much larger contact area.
  • They have minimum thickness so as to minimize the overall length of the joint.
  • They have chamfers specially designed to match fillet radiuses of NAS bolts (at the location where the bolt head meets the bolt shank).
  • They have tighter fitting inner diameters designed to clear NAS bolt shanks while at the same time maximizing coverage of the Nitinol cylinder.

Product Details

*Note: All values are approximate and for reference only. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

LOCK NUTS

The NAS1805 series locknuts shown on this page have been widely used with the Frangibolt release mechanism. They offer the following key features:

  • They are made from high strength A286 stainless steel with a minimum tensile strength of 180 ksi.
  • They are silver plated to reduce friction and minimize galling.
  • They have a locking feature in the form of a deformity in the thread.
  • They offer a higher profile than other NAS nuts thereby increasing the number of threads engaged and reducing the stress in the thread.

Note that not all Frangibolt designs require a nut as many thread directly into a flange or structure. In this case, it is important that the threaded connection be designed to withstand the tensile strength of the notched Frangibolt.

Product Details

*Torque specification is recommended value above running.
Note: All values are approximate and for reference only. Contact TiNi Aerospace for detailed ICD (Internal Control Drawing).

SUBSEA SWITCH WASHERS

The Subsea Switch Washers are designed to be used in direct sea water applications  and are qualified to operating pressure of 25 PSI.  The switch washer body has been sealed to prevent water intrusion and the cable and connector over molded to a greater degree to ensure resilience to salt water.  The Switch Washer is a combination Switch and Washer developed as a simple means of determining when the Subsea Frangibolt has functioned. It comprises of a top and bottom bearing surface, internally mounted belleville spring, and a pair of mating electrical contacts. The belleville spring is preloaded to generate more than 20 lbs of force to keep the top and bottom surfaces separated thereby firmly biasing the switch to the Open position. However, once installed on a bolted joint and tightened to the prescribed torque, the top and bottom surfaces are brought together closing the switch contacts and preloading the Frangibolt joint assembly. The switch contacts remain closed until the Subsea Frangibolt releases the tension by breaking the bolt during actuation. At this time, the belleville spring once again returns the Switch back to the Open position within a fraction of a second.

The Switch-Washer may be used in one of two ways: It can be wired in series with the Subsea Frangibolt actuator to act as an automatic shut-off switch, or it can be wired as part of a separate circuit to serve as a feedback loop to a controller.

Still want to learn more?

VISIT OUR FAQ

How can we assist in your project?

CONTACT US FOR A CUSTOM SOLUTION