Strain gauge with corrugated surface
By designing strain gauges with corrugated surfaces and buffers, the problem of insufficient sensitivity of traditional strain gauges has been solved, achieving high-precision strain measurement and stability in complex environments, thus expanding the application range.
Patent Information
- Application Number
- CN202520302618.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-25
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2035-02-25
AI Technical Summary
Traditional strain gauges have low strain transfer efficiency due to structural design limitations, making it difficult to achieve uniform strain distribution and lacking sensitivity, thus failing to meet the requirements of high-precision measurement.
The design incorporates a corrugated surface with a metal sheet in a corrugated shape, combined with a buffer to enhance strain transfer efficiency and sensitivity, and detects resistance changes via electrodes.
It improves the sensitivity and measurement accuracy of strain gauges, enhances mechanical stability, adapts to complex stress fields, reduces electromagnetic interference, and broadens the application range.
Smart Images
Figure CN223727062U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of sensors, in particular to a strain gauge with a corrugated surface. BACKGROUND
[0002] In engineering, judging the strain of an object surface is a key step for analyzing the force state of a structure, evaluating safety and optimizing design. As a sensor for measuring the strain of an object surface, a strain gauge is a core component of mechanical measurement, and its sensitivity directly determines the measurement accuracy and application range.
[0003] A strain gauge generally consists of a metal sheet, a substrate and a lead wire, and its working principle is based on the resistance strain effect. When the strain gauge is pasted on the surface of an object, the object deforms under force, and the metal sheet in the strain gauge deforms accordingly, causing a change in its resistance value. The change in the resistance value is measured by a measurement circuit connected by the lead wire, and the strain on the surface of the object is calculated. However, due to the limitations of structural design, the metal sheet of a traditional strain gauge is usually a planar straight structure, and the strain transfer efficiency is low. In a complex stress field, it is difficult to achieve uniform strain distribution. When measuring small strain, the resistance change is small, and it is easily affected by environmental noise and circuit interference, which has significant limitations, resulting in insufficient sensitivity and difficulty in meeting the needs of high-precision measurement.
[0004] Therefore, the traditional strain gauge has the problem of insufficient sensitivity in measuring the strain of an object surface, which limits its application in high-precision measurement fields such as micro-electro-mechanical systems and biomechanical detection. In order to solve this problem, a new strain gauge structure design is needed to improve the strain transfer efficiency and sensitivity. SUMMARY
[0005] The present application relates to the technical field of sensors, in particular to a strain gauge with a corrugated surface.
[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:
[0007] The present application provides a strain gauge with a corrugated surface, comprising a substrate, a metal sheet, a first electrode and a second electrode. The substrate is provided with a metal sheet, and the first electrode and the second electrode are respectively arranged on the surface of the two ends of the metal sheet away from the substrate. The metal sheet has a corrugated shape between the first electrode and the second electrode, and the corrugations are distributed along the length direction of the metal sheet. The substrate and the corrugated part of the metal sheet are matched in shape, and the substrate and the metal sheet are bonded at the interface.
[0008] The present application significantly improves the sensitivity and strain transmission efficiency of the strain gauge by designing a corrugated shape on the metal sheet. The core of the technical solution is to utilize the geometric characteristics of the corrugation to increase the effective length and amplify the local strain. When the substrate is subjected to external stress, the strain is transmitted to the metal sheet through the substrate. The corrugated shape causes the metal sheet to deform more when under stress, thereby directly increasing the resistance change rate. The corrugation not only effectively increases the length of the metal sheet by distributing in the length direction, but also forms stress concentration areas at the wave crests and troughs through the local strain concentration effect, further amplifying the local strain and causing the metal sheet to produce more significant resistance changes under the same external strain. In addition, the shape of the corrugation increases the effective contact area between the metal sheet and the substrate, optimizes the interface adhesion, reduces interface slip and stress concentration phenomena, and enables the strain energy to be more uniformly transmitted to the surface of the metal sheet, improving measurement accuracy and reducing the risk of local overload, while enhancing the mechanical stability of the metal sheet, allowing it to better adapt to curved surfaces and complex shapes, and expanding the application range. The corrugation design also disperses and attenuates the effects of external electromagnetic fields through its unique geometric shape, effectively suppressing electromagnetic interference and improving the signal-to-noise ratio of the measurement signal, ensuring measurement reliability in complex electromagnetic environments. The first electrode and the second electrode arranged on the surface of the metal sheet at both ends are used to detect resistance changes and output electrical signals. Under the action of external stress, the multiple optimization mechanisms of the corrugation work together to cause the metal sheet to produce more significant deformation and resistance changes, ultimately outputting high-sensitivity, high-signal-to-noise ratio electrical signals through the electrodes. This design not only solves the problem of insufficient sensitivity of traditional strain gauges, but also improves the accuracy and reliability of the measurement, while enhancing the mechanical stability and environmental adaptability of the strain gauge
[0009] Further, the corrugation is a periodic sawtooth-shaped protrusion. This shape can further concentrate stress distribution through its sharp geometric features, enhancing local deformation effects, making it suitable for high-sensitivity measurement scenarios.
[0010] Further, the period length of the corrugation is 50-500 , and the vertical distance between the wave crest and the wave trough of the corrugation is 5-50 . A too small period length of the corrugation may cause local stress concentration, reducing mechanical strength; a too large period length may reduce strain sensitivity, as the strain distribution is too dispersed. Preferably, the period length of the corrugation is 100-200 , which is optimal, achieving a good balance between sensitivity and mechanical strength. The vertical distance from the wave crest to the wave trough of the corrugation is the wave height, and a too small wave height may result in weak strain signals and insufficient sensitivity; a too large wave height may cause plastic deformation or rupture of the material, reducing reliability. Preferably, the wave height is 10-20 , which is optimal. At the same time, the matching relationship between the period length and the wave height also affects the sensitivity of the strain gauge, and the ratio of the period length to the wave height is between 10-15, which is optimal.
[0011] Further, the thickness of the metal sheet is 20-50 The thickness of the metal sheet is a key parameter in the design, directly affecting the performance of the strain gauge. A small thickness is more sensitive to strain, and can more effectively convert external strain into resistance change, but the mechanical strength of the metal sheet is low, and plastic deformation or fracture is prone to occur. A large thickness has high mechanical strength and is not prone to deformation or fracture, but its sensitivity is lower and the strain transmission efficiency is reduced. Preferably, the thickness of the metal sheet is 20-50 At the same time, the thickness of the metal sheet should match the wave height, specifically, the thickness is 2-5 times the wave height, to ensure the stability of the corrugation.
[0012] Further, a buffer is arranged in the bonding gap between the substrate and the metal sheet.
[0013] Further, the buffer is a high-flexibility material.
[0014] The buffer arranged in the bonding gap between the substrate and the metal sheet is made of a high-flexibility material, specifically, it can be silicone rubber or polyurethane in the form of a thin film. These materials can absorb and disperse external loads, reduce stress concentration at the interface between the metal sheet and the substrate, prevent local failure of the metal sheet, and improve the transmission efficiency of strain from the substrate to the metal sheet, reduce strain loss, and improve measurement accuracy. In addition, the buffer can also enhance the adhesion between the metal sheet and the substrate, prevent interface peeling, and ensure the long-term stability of the strain gauge. By reasonably designing the buffer, the performance and reliability of the metal strain gauge can be significantly improved. The corrugated shape of the metal sheet and the buffer form a synergistic effect, which not only utilizes the local strain amplification effect of the corrugated shape of the metal sheet, but also reduces stress concentration and strain loss at the interface through the buffer, further improving the strain transmission efficiency and sensitivity.
[0015] Further, the first electrode and the second electrode are electrically connected to the metal sheet. The electrical connection between the first electrode, the second electrode and the metal sheet is the core structure of the strain gauge to realize strain detection function. Through this connection, the strain gauge can convert mechanical deformation into measurable electrical signals, providing basic support for strain measurement.
[0016] Further, the material of the first electrode and the second electrode is a low-resistivity metal. In the strain gauge, the first electrode and the second electrode are connected to the lead wire to transmit resistance changes. In general, low-resistivity metal materials are preferred, which can efficiently transmit electrical signals.
[0017] Further, the material of the substrate is polyimide. Generally, the material of the substrate can be polyimide, aluminum oxide, stainless steel, carbon fiber reinforced polymer, etc., preferably, the material of the substrate is polyimide, which has the advantages of low elastic modulus, high flexibility, good thermal stability and insulation, and is suitable for high-sensitivity strain gauges.
[0018] Compared with the prior art, the utility model has the beneficial effects of:
[0019] (1) The metal sheet is designed in a corrugated shape, which can increase the effective length of the strain gauge, form stress concentration areas at the wave crests and troughs of the corrugations, further amplify local strain, produce more significant resistance changes under the same external strain, and thus improve strain transmission efficiency and sensitivity. In addition, the optimized design of the corrugated shape can disperse and attenuate the influence of external electromagnetic fields, reduce the influence of environmental noise on measurement results, improve the signal-to-noise ratio of the signal, better adapt to complex stress fields, realize more uniform strain distribution, and thus further improve measurement accuracy.
[0020] (2) The application sets a buffer between the metal sheet and the substrate, which serves as an intermediate layer, thereby reducing stress concentration and strain loss at the interface between the metal sheet and the substrate, ensuring efficient transmission of strain energy to the corrugated structure of the metal sheet, and further improving measurement accuracy and reliability. The high flexibility of the buffer can absorb and disperse external loads, prevent local failure, and enhance the adhesion between the metal sheet and the substrate to avoid interface peeling.
[0021] (3) The synergistic effect of the corrugated shape and the buffer not only utilizes the local strain amplification effect, but also avoids stress concentration at the interface, making the strain gauge have higher sensitivity and stability in complex stress environments. This design broadens the application of the strain gauge in high-precision measurement fields such as micro-electro-mechanical systems and biomechanical detection, and can also adapt to multi-directional stress measurement requirements, meeting the performance requirements of various application scenarios. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 A schematic diagram of a strain gauge with a corrugated surface is provided.
[0023] Figure legend: 1 - substrate; 2 - metal sheet; 3 - first electrode sheet; 4 - second electrode sheet. DETAILED DESCRIPTION
[0024] In order to make the implementation process of the utility model more clear, the following will be described in detail in conjunction with the drawings.
[0025] The utility model provides a kind of strain gauge with corrugated surface, such as Figure 1As shown, it includes a substrate 1, a metal sheet 2, a first electrode 3, and a second electrode 4. The metal sheet 2 is arranged on the substrate 1, and the first electrode 3 and the second electrode 4 are arranged on the surface of the metal sheet 2 away from the substrate 1. The metal sheet 2 has a corrugated shape between the first electrode 3 and the second electrode 4, and the corrugations are distributed along the length direction of the metal sheet 2. The substrate 1 is shaped to match the corrugated part of the metal sheet 2, and the interface between the substrate 1 and the metal sheet 2 is attached.
[0026] The corrugated shape of the metal sheet 2 can be prepared by photolithography, stamping, or laser processing, etc. These methods are simple and easy to implement, and can efficiently form the required corrugated shape. Specifically, the photolithography process can accurately control the period length and fluctuation height of the corrugations through the patterned exposure and development of photoresist, combined with chemical etching or electrochemical etching, to ensure the uniformity and consistency of the corrugated shape. The stamping process directly stamps the metal sheet 2 with high-precision molds, quickly forming the corrugated shape, with the advantages of high efficiency and low cost. Laser processing uses the high energy density of the laser beam to directly ablate the corrugated shape on the metal sheet 2, which is suitable for complex shapes and high-precision requirements. These processes not only have high preparation efficiency, but also can ensure the uniformity and consistency of the corrugated structure, thereby ensuring the high sensitivity and reliability of the strain gauge in actual application. In addition, these processes have good repeatability and scalability, which can meet the demand of large-scale production, providing a flexible and reliable solution for the preparation of corrugated shape.
[0027] The corrugated shape of the metal sheet 2 is a periodic sawtooth-shaped protrusion. This sawtooth-shaped protrusion can further concentrate stress distribution through its sharp geometric features, enhancing the local deformation effect, which is suitable for measurement scenarios requiring high sensitivity. In addition, the corrugated shape of the metal sheet 2 can also be designed in various forms according to actual needs, such as sinusoidal waveforms, etc. The sinusoidal waveform can uniformly distribute stress through its smooth curve characteristics, adapting to the measurement requirements of multi-directional stress, and is suitable for applications in complex stress environments. Figure 1 This is only a schematic diagram, and the purpose is to facilitate the intuitive display of the corrugated shape of the metal sheet 2. It should be noted that in actual application, the metal sheet 2 usually adopts a grid structure, and the surface corrugation can be selected in different wave shapes according to the purpose of the strain gauge and the stress distribution characteristics. Through the above design, the corrugation of the metal sheet 2 not only can significantly improve the sensitivity and measurement accuracy of the strain gauge, but also can flexibly adjust the wave shape according to actual needs to meet the performance requirements in different application scenarios. This flexibility and customizability design makes the strain gauge have higher adaptability and reliability in complex stress environments and diversified application scenarios.
[0028] The periodic convex corrugation of the metal sheet 2 realizes efficient strain transfer and local deformation amplification under external stress through its unique geometric characteristics. The external strain is concentrated at the peaks and troughs of the corrugation of the metal sheet 2, increasing the local deformation of the metal sheet 2, while effectively increasing the length of the metal sheet 2 through the periodic corrugation, making the resistance change more significant. The period length of the corrugation is 50-500 , the wave height of the corrugation is 5-50 , the range is selected to achieve the best balance between sensitivity and mechanical strength. Preferably, the period length of the corrugation is 100-200 , and the wave height is 10-20 . Optimal. At the same time, the matching relationship between the period length and the wave height also affects the sensitivity of the strain gauge, and the ratio of the period length to the wave height is between 10-15 for optimal.
[0029] The thickness of the metal sheet 2 is a key parameter in the design, which directly affects the performance of the strain gauge. Small thickness is more sensitive to strain, which can more effectively convert external strain into resistance change, but the mechanical strength of the metal sheet is lower, and it is easy to deform or break; large thickness has high mechanical strength and is not easy to deform or break, but its sensitivity is lower and the strain transfer efficiency is lower. Preferably, the thickness of the metal sheet 2 is uniform, and the thickness range is 20-50 . At the same time, the thickness of the metal sheet 2 should match the wave height of the corrugation, specifically, the thickness is 2-5 times the wave height, to ensure the stability and durability of the corrugation shape under stress.
[0030] A buffer is provided in the bonding gap between the substrate 1 and the metal sheet 2. The buffer is made of a material with low elastic modulus and high flexibility, such as silicone rubber or polyurethane, and is coated in the form of a uniform film between the substrate 1 and the metal sheet 2. The buffer can effectively transfer the strain of the substrate 1 to the metal sheet 2, improve the strain transfer efficiency, reduce strain loss, and thus improve the sensitivity of the strain gauge; at the same time, it can absorb and disperse external load, reduce stress concentration at the interface between the substrate 1 and the metal sheet 2, and prevent local failure of the metal sheet 2; it can also enhance the adhesion between the metal sheet 2 and the substrate 1, and prevent interface peeling. The corrugated shape of the metal sheet 2 can form a synergistic effect with the buffer, which not only utilizes the local strain amplification effect of the corrugated shape of the metal sheet 2, but also reduces the stress concentration and strain loss at the interface through the buffer, further improving the strain transfer efficiency and sensitivity.
[0031] The thickness of the buffer is controlled between 10-30 , too thin may cause the interface to be not firm, and too thick will reduce the strain transfer effect, 10-30 The range of the interface bonding strength and the strain transmission efficiency is the preferred value. By optimizing the material and thickness of the buffer, the sensitivity and measurement accuracy of the strain gauge can be significantly improved while ensuring mechanical strength.
[0032] The first electrode 3 and the second electrode 4 are electrically connected with the metal sheet 2, which is the core structure of the strain gauge for strain detection function. Through this connection, the strain gauge can convert the mechanical deformation of the metal sheet 2 into a measurable electrical signal, providing basic support for strain measurement. This design not only improves measurement accuracy, but also simplifies the structure and enhances practicality.
[0033] The material of the first electrode 3 and the second electrode 4 is preferably low resistivity metal such as gold, silver or copper to ensure efficient transmission of electrical signals, preferably copper which is less expensive. The electrode material also needs to have good tensile strength and ductility to withstand mechanical stress during installation and use. The first electrode 3 and the second electrode 4 are connected with the metal sheet 2 by welding or crimping to ensure reliable transmission of electrical signals.
[0034] The selection of the substrate 1 material is crucial. If the material is too soft, it cannot provide stable support for the metal sheet 2 and is prone to deformation affecting measurement accuracy; if the material is too hard, it cannot effectively transmit the strain effect. Generally, the material of the substrate 1 can be polyimide, alumina, stainless steel, carbon fiber reinforced polymer, etc. Specifically, the material of the substrate 1 can be selected according to the mechanical properties, thermal stability, insulation and cost requirements. Preferably, the material of the substrate 1 is polyimide, which has the advantages of low elastic modulus, high flexibility, good thermal stability and insulation, suitable for high sensitivity strain gauge. The thickness of the substrate 1 can be optimized according to specific application requirements, usually between 50-200 μm, to balance mechanical support and strain transmission efficiency.
[0035] When external stress acts on the substrate 1, the substrate 1 will transmit the strain to the metal sheet 2. The buffer between the substrate 1 and the metal sheet 2 can better transmit the strain and reduce the strain loss. Since the surface of the metal sheet 2 has corrugations, the corrugation shape makes the metal sheet deform when stressed, and also forms stress concentration areas at the wave crests and troughs of the corrugations through the local strain concentration effect, further amplifying the local strain, so that the metal sheet 2 produces greater deformation under the same external strain. According to the resistance strain effect, the resistance change of the metal sheet 2 is proportional to the length change, and the corrugations significantly improve the resistance change rate by increasing the effective length of the metal sheet 2 and local stress amplification, thereby enhancing the sensitivity of the strain gauge. The first electrode 3 and the second electrode 4 are arranged on the surface at both ends of the metal sheet, for detecting the resistance change of the metal sheet 2. When the substrate 1 is subjected to external stress, the strain is transmitted to the metal sheet 2 through the buffer, and the corrugations make the metal sheet 2 produce greater deformation, resulting in more significant resistance change, and finally outputting a high-sensitivity electrical signal through the first electrode 3 and the second electrode 4.
[0036] In practical applications, the signal of the strain gauge is measured by a Wheatstone bridge. The Wheatstone bridge is composed of four resistors, one of which is the resistance of the strain gauge, and the other three are known resistors. When the strain gauge is subjected to stress, its resistance changes, causing the bridge to lose balance and generate a voltage signal proportional to the resistance change. After amplification and filtering, the voltage signal is converted into a digital signal by an analog / digital converter, and then collected and analyzed by software. By measuring the output voltage of the bridge, the resistance change of the strain gauge can be accurately calculated, and thus the size and direction of the external stress can be determined. The role of the Wheatstone bridge is to convert the small resistance change into a measurable voltage signal, and through the subsequent signal processing circuit, high-precision strain measurement is realized.
[0037] In summary, the strain gauge of the present application can significantly improve the sensitivity, optimize the strain transmission efficiency, and enhance the mechanical stability, and is suitable for various measurement scenarios such as high-precision strain, and has a wide application prospect.
[0038] The above is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can be variously modified and changed. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A strain gauge having a corrugated surface comprising a substrate, a metal sheet, a first electrode, a second electrode, characterized in that: The metal sheet is arranged on the substrate, the first electrode and the second electrode are respectively arranged on the surfaces of the two ends of the metal sheet away from the substrate, the metal sheet has a corrugated shape between the first electrode and the second electrode, the corrugations are distributed along the length direction of the metal sheet, the substrate is matched with the corrugated part of the metal sheet in shape, and the substrate and the metal sheet are in interface fit.
2. The strain gage with corrugated surface according to claim 1, characterized in that: The corrugations are periodic sawtooth-shaped protrusions.
3. The strain gage with corrugated surface according to claim 2, characterized in that: the period length of the corrugations is 50-500 the vertical distance between the crests and troughs of the corrugations is 5-50 .
4. The strain gage with corrugated surface according to claim 3, wherein: The thickness of the metal sheet is 20-50 .
5. The strain gage with corrugated surface of claim 1 wherein: A buffer is arranged in the fit gap between the substrate and the metal sheet.
6. The strain gage with corrugated surface of claim 5 wherein: The buffer is a high-flexibility material.
7. The strain gage with corrugated surface of claim 1 wherein: The first electrode and the second electrode are electrically connected with the metal sheet.
8. The strain gage with corrugated surface of claim 1 wherein: The first electrode and the second electrode are low-resistivity metal materials.
9. The strain gage with corrugated surface of claim 1 wherein: The material of the substrate is polyimide.