FiberStrike LCM-200 Series Brainy Bolts
A patented FBG insert that turns an ordinary structural fastener into a smart fastener, continuously measuring bolt elongation and tension. The insert is fitted into a bored and threaded fastener.
Technical overview
A Brainy Bolt contains a pre-tensioned, pre-calibrated Fiber Bragg Grating that reflects a specific wavelength back to an optical interrogator; a change in fastener tension shifts that wavelength and is converted to a tension measurement. Each FBG can be tuned to a unique wavelength so many inserts share one fiber while remaining individually addressable. All Brainy Bolts provide individual temperature compensation through the same internal fiber. CEL states the modification has no effect on the ultimate tensile strength of a fastener of any alloy at or above 0.5 inch diameter, although stiffness is reduced and there is a small effect on shear strength.
Features
- Sensor may be integrated into virtually any bolt, rivet, stud or screw having a body diameter of 12.7mm / 0.50" or greater
- Integration of sensor in fastener has no effect on ultimate tensile strength of fastener
- 20-30 sensors may be multiplexed on a single optical fiber
- Contain no electronic components, require no electrical power, and emit no signals
- Individual temperature compensation capability using the same internal fiber
- Delivered with the internal FBG slightly pre-tensioned and pre-calibrated
- Pre-installed armored optical fiber pigtail, available in various lengths
- Tamper-resistant head requiring CEL part number LCM-255 installation tool
Specifications
| Parameter | Value |
|---|---|
| Minimum fastener body diameter | 12.7 mm / 0.50 in |
| Sensors multiplexed on a single optical fiber | 20-30 |
| Maximum interrogator-to-sensor distance | up to 25+ km |
| Pigtail fiber type | single-mode 1550nm, armored, spliced nm |
| Effect of fastener modification on ultimate tensile strength | none (for any alloy at diameter of at least 0.5 inch) |
| Required installation tool | LCM-255, with 1/4" drive torque wrench adjustable in inch-pounds |
Applications
- Structural fastener tension monitoring
- Bridge and civil structure monitoring
- Industrial machinery fastener monitoring
- Hazardous environment structural monitoring
- Remote or difficult-to-access fastener locations
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