An in-situ freezing detection method based on the freezing interface micromechanics

Materials exhibit distinct linear expansion coefficients, while water undergoes volume expansion as it freezes. This study introduced an in-situ method for detecting freezing based on the differences in linear expansion coefficients between water and various materials under low-temperature conditions. That is, based on the fact that water has different coefficients of expansion before and after freezing, it is possible to identify the state of water adhering to the material surface by comparing the strain caused by water freezing with the contraction strain of the substrate. Changes in freezing-induced interface strain were examined and discussed across various ambient temperatures and substrates. The conducted analyses indicated that water on the cold surface undergoes a rapid phase change and expands as the ambient temperature decreases, leading to an increase in the interface strain. Notably, due to the lower expansion coefficient of copper compared to aluminum alloy, the adhesion strain measured with water attached to copper was higher than that on the aluminum alloy under the same conditions. Validation tests conducted in both controlled indoor and natural outdoor settings confirmed that the proposed in-situ freezing detection system could accurately and promptly monitor the state of water on material surfaces. The proposed in-situ freezing detection method can offer the advantages of simple implementation and low cost, providing a new approach for freezing detection methods in the engineering field and contributing to the advancement of freezing detection sensors.