Curved Strain Sensors: Model DT3747 Series

The DT3747 sensors from Columbia were created to precisely detect strain on curved mounting surfaces. The precision, robustness and easy installation of the flight-qualified Series DTD2684 are all present in these sensors. Similar systems have been used to track the growth of rocket motors.

These sensors may also be utilized in a variety of industrial and military applications, such as pipe expansion measures, explosive body applications, aircraft surface load and all forms of engine monitoring.

The sensors in the Series DT3747 are designed to detect circumferential strain around the diameter of the material to which they are attached. The required mounting radius is specially molded into the sensor’s body, allowing for operator alignment control during sensor installation.

Models are provided to correct for typical materials used in aircraft structural manufacturing, as well as alternative materials as needed. The Columbia Model 5802 Strain Gage Amplifier can also be used to power and signal condition the sensor’s strain output.

Note: Exports from the United States are subjected to the Export Administration Regulations (EAR) and/or the International Traffic in Arms Regulations (ITAR) authorization procedures.

  • Strain Outputs
  • Self-Temperature Compensating
  • Choice of Cylindrical Mounting Radius

Specifications

Operational

Table 1. Source: Columbia Research Laboratories, Inc.

Operational 1 Series DT3747
DC Input Resistance 1000 Ω, ±2%
DC Output Resistance 1000 Ω, ±2%
Sensitivity 1,025 (±1%) mV/V/1000 μϵ
Rated Excitation Voltage 10.0 VDC
Linearity ±0.5% Max.
Zero Strain Offset ±0.5 mV/V Max.
Operating Range -3500 to +5000 μϵ
Sensitivity Shift ±0.005% / °F
Hysteresis, Repeatability ±0.013% Max.
Zero Shift ±0.00025 mV/V/°F Typ.
Creep <0.5%, 5 Min. @ 5000 μϵ

 

Environmental

Table 2. Source: Columbia Research Laboratories, Inc.

Environmental 2 Series DT3747
Temperature Range -54° to +125 °C
Vibration 30 g, 10 Hz to 2 KHz
Humidity MIL-STD-202 Method 103B
Salt Spray MIL-STD-202 Method 101D (168 Hours)
Insulation Resistance 100 Meg. min @ 500 VDC
Dielectric Strength 1050 VRMS, 60 Hz, 1 Min.
Altitude Sea Level to 70,000 Ft.
Shock 100 g, 11 mSec
Flammability MIL-STD-202 Method 111A
Fluids Resistance to short term exposure to fuel, lubricating oils and hydraulic fluids

 

Physical

Table 3. Source: Columbia Research Laboratories, Inc.

Physical Series DT3747
Size 0.562"Sq (Thickness Varies w/ Specified Mounting Radius)
Encapsulation Silicone Rubber per MIL-S-23586A Type I, Class 2, Grade A
Weight Approx. 15 gms (Depending on radius selected)
Matrix 0.001" Polyimide
Leads #26AWG, Teflon Ins, SPC, 24" Nom.

 

1 @25 °C. 2 Installed Gage

Schematic Diagram

Curved Strain Sensors: Model DT3747 Series

Image Credit: Columbia Research Laboratories, Inc.

Typical Installation of Old Style Strain Gages. 1. Bolt or rivet removed from assembly; 2. Dummy gage(s) bonded to “Z Tab” of same material as structure; 3. Active gage bonded to structure under test; 4. “Z Tab” mounted to structure with bond or rivet; 5. Strain gage leads interwired and soldered to junction block; and 6. Entire unit covered with protective material.

Typical Installation of Old Style Strain Gages. 1. Bolt or rivet removed from assembly; 2. Dummy gage(s) bonded to “Z Tab” of same material as structure; 3. Active gage bonded to structure under test; 4. “Z Tab” mounted to structure with bond or rivet; 5. Strain gage leads interwired and soldered to junction block; and 6. Entire unit covered with protective material. Image Credit: Columbia Research Laboratories, Inc.

Installation of Columbia Strain Sensor. 1. Strain Sensor bonded to surface under test; 2. Leads connected to wire harness;  and 3. Coat sensor and wires with waterproofing material.

Installation of Columbia Strain Sensor. 1. Strain Sensor bonded to surface under test; 2. Leads connected to wire harness;  and 3. Coat sensor and wires with waterproofing material. Image Credit: Columbia Research Laboratories, Inc.

Ordering Information*

Table 4. Source: Columbia Research Laboratories, Inc.

Model Lead Length Compensating Material
DT3747-1 24" Aluminum 7075-T6 or 7050-T73651, IVD
DT3747-2 24" Steel, AISI 4130 or HP9-4-.20
DT3747-3 24" Titanium TI-6AL-4V Annealed
DT3747-4 24" Carbon/Epoxy MMS 549 Type 1

 

*Mounting Radius Required upon Ordering

Advantages

  • Twice as much output
  • A higher level of precision
  • No compromise on structural integrity
  • Installation time is reduced
  • Optimal temperature compensation

Other Equipment by this Supplier