soft strain sensor

The key difference lies in the substrate. Foil gauges use a rigid backing that limits the amount of elongation they can accommodate before the bond line fails. Soft strain sensors use a flexible polymer substrate that can stretch with the underlying material, making them better suited for materials like plastics, rubber, or concrete that may experience moderate strain beyond the elastic limit. This flexibility also reduces stress concentration at the edges, improving reliability on curved surfaces.

Yes, with the right sealing. Kingmach provides versions with an additional waterproofing layer or encapsulation that withstands long-term burial. For temporary submersion, such as monitoring during a flooding event, the standard coating may be sufficient, but for permanent immersion, a fully potted assembly is recommended. Technical support can advise on the appropriate protection for your specific site conditions.

Installation starts with surface preparation: grinding or sanding to a smooth profile, followed by cleaning with a solvent. A two-part adhesive is often used, chosen for its compatibility with both the sensor substrate and the concrete. The sensor is pressed into place and held under light pressure while the adhesive cures. A thin layer of protective coating is then applied over the sensor and lead wires to prevent mechanical damage and moisture ingress. For large arrays, pre-assembled multi-sensor sheets can be supplied to reduce on-site handling.

Yes, Kingmach can adjust both the nominal resistance (common values are 120, 350, or 1000 ohms) and the gage factor to suit different measurement systems. Higher resistance reduces current draw for battery-powered loggers; higher gage factor increases signal output for the same strain. Because these sensors are built to order, you can specify the electrical characteristics and the dimensions of the sensing grid. Lead time varies with quantity and complexity, but typical prototyping runs take a few weeks.

In a static pile load test, sensors are attached along the pile shaft to measure strain distribution under applied load. The flexibility of soft sensors allows them to be placed on circular or irregular pile surfaces without bridging gaps, and their low profile does not interfere with the pile driving process. Multiple sensors at each elevation provide redundancy, and the data can be used to derive load transfer curves. Kingmach offers pre-wired arrays with connectorized terminations that speed up installation on site.