HBM Strain Gauges for High Temps & Alternating Load Resistance (2024)

FAQs

What is the maximum temperature for a strain gauge? ›

Strain gauges covering the range 200ºC to 1325ºC offering strain gauges in a variety of configurations and mounting methods. Foil strain gauges can be supplied for up to 700ºC and wire gauges are used up to and sometimes beyond 1350ºC.

Such high-resistance strain gauges are specially demanded in the applications of low power consumption, for instance the applications of battery-powered devices or systems such as the wireless sensors and wireless sensor networks, and remote or portable testing equipment.

The use of the strain gauge LD20 is recommended wherever an extremely high strain or compression can occur (>5 %). The LD20 has a maximum elongation of +/- 100,000 µm/m (+/-10 %) and is attached with 30 mm leads.

With all strain gages in a bridge at the same temperature and mounted on the same material, any changes in temperature affect all gages in the same way. Because the temperature changes are identical in the gages, the ratio of their resistance does not change, and the output voltage of the gage does not change.

Limited Measurement Range: Each strain gauge has a specific measurement range, beyond which it may not provide accurate readings. This limitation restricts their application in cases where high strains are expected, such as during dynamic load testing or extreme events like earthquakes.

So the device can not be used to measure pressure. Strain guage: A Strain gauge (sometimes referred to as a Strain gage) is a sensor whose resistance varies with applied force; It converts force, pressure, tension, weight, etc., into a change in electrical resistance which can then be measured.

The choice of resistance of a strain gauge is dependent on the overall size of the gauge grid, cost, and certain performance parameters. A higher resistance gauge is preferred when the requirement is to reduce the heat generation rate.

Considering the mounting, strain gauges can be either bonded or unbonded, and based on the construction, we can have foil, semiconductor, and photoelectric strain gauges.

The strain gauge resistance changes differ in tension load cells vs. compression load cells. Tension force causes the strain gauge to get thinner and longer, increasing the resistance. Compression force causes the strain gauge to get thicker and shorter, decreasing resistance.

Gage Resistance – The lower the gauge resistance, the more current/power (P=V^2/R) drawn for a given excitation. For example, a 120 Ohm gauge will have worse thermal performance than a 350 Ohm gauge, because it draws more power for a given voltage.

Which type of strain gauge is the most sensitive and reliable? ›

Half-bridge strain gages are two times more sensitive than quarter-bridge strain gages.

Measurement Accuracy

Accuracies of 0.5% to 1% are typical for strain gages with a measurement limit of up to 5% strain (50,000 µε). The accuracy of DIC strain measurements tends to be around 10% below 0.3% strain (3,000 µe), with higher accuracies near 1% above 3% strain (30,000 µe).

Please be aware: The temperature range of foil strain gauges is limited by the materials that are used. The maximum range is about 300°C to 400°C. If measurements have to be conducted at higher temperatures, high-temperature strain gauges that work according to different principles must be used.

Problem #2: Temperature Changes

Temperature changes affect the conductivity of metals. This will change the output of the strain gauge. Once the load cells are built, they must be tested at different temperatures in order to ascertain their drift with temperature.

Self-compensated strain gauges are specially developed to compensate for the temperature behavior of certain materials by their own temperature behavior. This means that they counteract the apparent strain (and thus the temperature-induced expansion of the measuring body).

Self-compensated strain gauges are specially developed to compensate for the temperature behavior of certain materials by their own temperature behavior. This means that they counteract the apparent strain (and thus the temperature-induced expansion of the measuring body).

Non-liquid-filled gauges with standard glass windows can withstand continuous operating temperatures up to 250 °F (121 °C). Liquid-filled pressure gauges can withstand 200 °F (93 °C) but glycerin fill and acrylic windows will tend to yellow.

The Planck temperature is the highest temperature in conventional physics because conventional physics breaks down at that temperature. Above 10³² K—that is, earlier than one Planck time—calculations show that strange things, unknown things, begin to happen to phenomena we hold near and dear, like space and time.

Hot. 44 °C (111.2 °F) or more – Almost certainly death will occur; however, people have been known to survive up to 46.5 °C (115.7 °F). 43 °C (109.4 °F) – Normally death, or there may be serious brain damage, convulsions, and shock. Cardio-respiratory collapse will likely occur.