Weldable strain gauges for static and dynamic strain measurement

Weldable strain gauges for demanding measurement conditions

Weldable strain gauges are designed for measuring mechanical strain on metal components where adhesive bonding may be unsuitable. They are attached to the test specimen using a dedicated spot welder, creating a mechanical connection between the strain gauge backing and the metal surface.

Althen's AW Series includes models for static and dynamic strain measurements, with selected versions suitable for temperatures ranging from −196°C to +800°C. Depending on the model, stainless steel or Inconel backing materials and different bridge configurations are available.

When should you use weldable strain gauges?

Weldable strain gauges can be considered when conventional adhesive bonding is difficult or unsuitable, particularly for measurements on compatible metal surfaces.

Typical application conditions include:

• Elevated temperatures where conventional adhesives may not meet the operating requirements.
• Long-term measurements where a spot-welded installation is preferred.
• Static or dynamic strain measurements on metal structures and components.
• Test environments requiring mechanically robust installation methods.

Static vs. dynamic strain measurement

Static strain measurements involve slowly changing or sustained loads. These measurements require attention to temperature-related output, zero-point stability and long-term drift.

Dynamic strain measurements involve time-varying loads, such as vibration or cyclic loading. In these applications, frequency response, signal conditioning and fatigue performance are important considerations.

Some AW Series models support both static and dynamic measurements, while others are designed specifically for dynamic measurement. The appropriate model and measurement electronics should therefore be selected together.

What should you consider when selecting a weldable strain gauge?

• Test material: Confirm that the metal specimen is suitable for spot welding and that the gauge backing material is compatible.
• Operating temperature: Check the temperature limits for static and dynamic measurements separately, where specified.
• Bridge configuration: Select the appropriate quarter-, half- or full-bridge measurement arrangement and any required compensation circuitry.
• Installation equipment: Verify the specified spot welder and installation procedure.
• Measurement conditions: Consider strain range, measurement duration, thermal effects and cyclic loading.
• Available space: Choose gauge dimensions and cable routing appropriate for the measurement location.

Always consult the individual product datasheet for operating limits, bridge wiring, temperature compensation and installation requirements.