CN-116399220-B - Strain sensing sensitive unit based on nickel-titanium alloy wire

Abstract

The invention provides a strain sensing sensitive unit based on a nickel-titanium alloy wire, which comprises a base material, a plating layer and a micro-slit structure, wherein the base material is the nickel-titanium alloy wire; the invention has the advantages that the plating layer is carried out on the surface of the nickel-titanium alloy wire, and the cyclic loading and unloading training of 8% of maximum strain is carried out on the nickel-titanium alloy wire after the plating layer, so that the plating layer on the nickel-titanium alloy wire forms a stable micro-slit structure, and compared with the prior art, the strain sensing sensitive unit can realize high sensitivity and large strain sensing simultaneously in the use process, and has important significance for the strain sensing application field of an intelligent system.

Inventors

• LIN JIANPING
• LI YONGJI
• ZHAO ZHIHAO
• MIN JUNYING

Assignees

• 同济大学

Dates

Publication Date

20260505

Application Date

20230425

Claims (3)

1. 1. A strain sensing element based on nitinol wires, comprising: The base material is nickel-titanium alloy wire, the diameter of the nickel-titanium alloy wire is less than or equal to 0.2mm, and the maximum recoverable strain of the super elastic property stretching of the nickel-titanium alloy wire is 8%; the coating is obtained by uniformly forming a coating material on the surface of the base material in an electroplating manner, wherein the coating material is any one of graphene, copper, zinc and aluminum, the thickness of the coating is 1-10 mu m, and The micro slit structure is obtained by performing cyclic loading and unloading training of 8% maximum strain on the substrate after the plating layer is obtained and cycling for 500-1000 times, The strain sensing unit divides deformation into two stages according to different sensitivities, and the strain sensing unit comprises: The first stage is that the strain is less than 0.5%, the micro slit structure is gradually opened, the whole resistance of the strain sensing unit is determined by the contact resistance of the micro slit structure, the sensitivity of the strain sensing unit is 200, and In the second stage, the strain is 0.5 percent <8 percent, the micro-slit structure is fully opened, the overall resistance of the strain sensing sensitive unit is determined by the self resistance of the matrix, and the sensitivity of the strain sensing sensitive unit is 5.
2. 2. The nickel-titanium alloy wire-based strain sensing unit according to claim 1, wherein the nickel-titanium alloy wire is made of a material with a nearly equal atomic ratio, and the mass ratio of nickel element in the material is 54.5% -57.0%.
3. 3. The nitinol wire-based strain sensing cell of claim 2, wherein the nitinol wire material has an austenite transformation ending temperature of less than 15 ℃.

Description

Strain sensing sensitive unit based on nickel-titanium alloy wire Technical Field The invention relates to the technical field of sensors, in particular to a strain sensing sensitive unit based on nickel-titanium alloy wires. Background Deformation of structures or materials is extremely critical engineering information. The engineering is mainly to obtain deformation information by arranging or embedding strain sensors on the surface of an object. The existing strain sensors mainly comprise metal strain gages, optical fiber strain sensors, capacitive strain sensors and piezoelectric strain sensors, however, the common strain sensors are difficult to realize high-sensitivity and wide-range strain sensing at the same time. In order to solve the problem, the invention introduces a new intelligent material-nickel-titanium alloy. The nickel-titanium alloy has the characteristics of shape memory effect, super elasticity, high corrosion resistance and the like. And the maximum recoverable strain value of the nickel-titanium alloy can reach 8%, wherein the resistance of the nickel-titanium alloy changes along with the strain, and the self sensitivity (the ratio of the resistance change rate to the strain) is about 4-5. In addition, nickel titanium alloys have higher recoverable strain values and higher sensitivities than typical metal strain gages (typical metal recoverable strain values <2%, sensitivities of about 2). Correspondingly, the micro-slit structure can be designed and prepared on the surface of the nickel-titanium alloy, and the sensitivity of the micro-slit structure is more than 200, so that the effect of high sensitivity and wide-range characteristics can be achieved in the use process. Disclosure of Invention The invention aims to solve the problems in the prior art, and provides a strain sensing sensitive unit based on nickel-titanium alloy wires. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: A strain sensing unit based on nickel-titanium alloy wires comprises a base material, a plating layer and a micro-slit structure formed by plating and cyclic loading and unloading training on the surface of the base material. The strain sensing sensitive unit based on the nickel-titanium alloy wire can also have the technical characteristics that the base material is the nickel-titanium alloy wire. The strain sensing sensitive unit based on the nickel-titanium alloy wire provided by the invention can also have the technical characteristics that the nickel-titanium alloy wire is made of a material with nearly equal atomic ratio, and the mass ratio of nickel element in the material is 54.5% -57.0%. The strain sensing sensitive unit based on the nickel-titanium alloy wire provided by the invention can also have the technical characteristics that the austenite phase transition end temperature of the nickel-titanium alloy wire material is less than 15 ℃. The strain sensing sensitive unit based on the nickel-titanium alloy wire can also have the technical characteristics that the diameter of the nickel-titanium alloy wire is less than or equal to 0.2mm, and the maximum recoverable strain of the superelastic attribute of the nickel-titanium alloy wire is 8%. The strain sensing sensitive unit based on the nickel-titanium alloy wire provided by the invention can also have the technical characteristics that the resistance of the nickel-titanium alloy wire changes along with the strain, and the self sensitivity of the nickel-titanium alloy wire is 4-5. The strain sensing sensitive unit based on the nickel-titanium alloy wire can be further characterized in that the micro-slit structure is formed by a plating material, and the plating material is graphene or any one of copper, zinc, aluminum and other materials with low resistivity. The strain sensing sensitive unit based on the nickel-titanium alloy wire can be further characterized in that the plating material forms a uniform plating layer on the surface of the substrate in an electroplating mode, and the thickness of the plating layer is 1-10 mu m. The strain sensing sensitive unit based on the nickel-titanium alloy wire can be further characterized in that the substrate after the plating layer is obtained is subjected to 8% maximum strain cyclic loading and unloading training and is circulated for 500-1000 times, so that a micro slit structure is obtained. The strain sensing sensitive unit based on the nickel-titanium alloy wire can be further characterized in that the strain sensing sensitive unit divides deformation into two stages according to different sensitivities, and comprises the following steps: The first stage, strain is less than 0.5%, the micro slit structure is gradually opened, and the whole resistance is determined by the contact resistance of the micro slit structure; and in the second stage, the strain is more than 0.5%, the micro-slit structure is fully opened, and the integral resistance is det