Strain measurement (tensometry) is a set of methods for determining mechanical stress in materials and structures. The method is based on measuring deformations or other changes in material parameters caused by mechanical stress. Instruments for strain measurement are called strain measurement stations or, for short, strain stations.
BAU-Monitoring has developed and serially produces a line of strain gauge sensors and 8-channel strain stations — data acquisition and transmission devices USD-A8 and strain stations USD4 — for obtaining both dynamic and static data when monitoring engineering structures.
Purpose of Strain Gauges
In manufacturing strain sensors, we exclusively use foil strain gauges made of foil no more than a few micrometers thick. The foil material is typically a Ni-Cu or Ni-Cr alloy. Foil strain gauges are designed for measuring deformations during testing of various structures, machine parts, and equipment under static and dynamic loads, as well as for measuring stresses caused by impact loading.
Description of Strain Gauges and Sensors
Structurally, strain gauges consist of a sensing element made of thin metal foil. The sensing element is protected by a film layer from external influences. Strain gauges are designed for one-time bonding and are non-recoverable products.
The operating principle of strain gauges is based on the property of conductors to change their electrical resistance when deformed — the so-called piezoresistive effect.
A wide range of strain gauges of various configurations is produced:
- Uniaxial strain gauges — capable of measuring tensile or compressive deformations under uniaxial stress state
- Biaxial, triaxial, and tetraaxial strain gauge rosettes — with corresponding arrangement of sensing elements on one substrate at a specific angle (45°, 90°, 120°, 180°)
Application of Strain Sensors
Foil strain gauges are versatile and cost-effective, which accounts for their widespread use in various measurement applications. The market offers a wide range of sensors with strain bridges that can be connected to our strain stations:
- Strain deformation sensors
- Crack opening displacement sensors
- Pressure sensors
- Soil pore pressure sensors
- Force sensors
- Linkage displacement sensors for distances up to 1 m
- Strain sensors for automotive and railway weighing platforms
Strain Measurement Stations
Strain measurement stations are designed for measuring, recording, and analyzing deformations and mechanical stresses in elements of building structures, machine parts, and mechanisms. The strain station receives input data from strain deformation sensors. When using mechanical deformation sensors with analog output signals, the strain station includes a module of precision measuring amplifiers that convert the analog signal to digital.
Data Acquisition and Transmission Device USD-A8
Purpose: strain station measuring amplifier for converting signals from eight strain gauge half-bridges to the digital RS-485 standard.
- Operating mode: long-term continuous or periodic monitoring systems
- Application: building small autonomous testing systems or large distributed data acquisition systems
- Package: supplied with or without enclosure
- Installation constraints: recommended to be placed in close proximity to sensors (no more than 10 m)
- Enclosure: 8-channel version in a plastic housing. Number of cable glands per enclosure — up to 10 pcs. (determined by the number of connected sensors)
Module USD-A6 (accelerometer-inclinometer-strain gauge)
A unique single-board module containing a strain station measuring amplifier for 3 channels + a 2-axis inclinometer + a 3-axis accelerometer.
- Functionality: signal registration, real-time digital processing, deformation visualization, automatic issuance of control signals to change the operating mode of the tested structure
- Measurement modes: suitable for both static and dynamic measurements
- Purpose: creating affordable comprehensive monitoring systems for engineering structures, machines, and mechanisms to control deformations, tilt angles, and vibrations
System Integration and Scalability
Combining USD-A8 and USD-A6 with an SMIS server based on the MS4812 controller allows creating a distributed system of up to 224 strain measurement channels.
Compatibility with other company solutions — quartz sensors, inclinometers, deformometers, accelerometers — allows building full-scale structural health monitoring systems (SMIS).
Order and Consultation
To purchase strain sensors or strain stations, clarify connection diagrams, and other information, please contact bau_monitoring@mail.ru or call +7 (916) 514-88-69.
Prices for strain sensors and strain stations are flexible and depend on order urgency, quantity of products, and other factors.