Fiber bragg grating high-load acceleration sensor

Abstract

A base is arranged on a base, the base is in a cylinder shape or an elliptical cylinder shape, a circle of groove is machined in a plane, perpendicular to a center line, of the outer surface of the base, a fiber bragg grating is arranged in the groove, the length of a grating region of the fiber bragg grating is 10 mm, the wavelength of the grating region of the fiber bragg grating is 1510-1565 nm, two connecting holes are machined in the right end of the base in the radial direction, and the two connecting holes are connected with the fiber bragg grating. The two sides of the connecting hole are symmetrically provided with the sensitizing holes, so that the weight of the sensor is reduced, the strength of the sensor is improved, the elastic strain is reduced, the inherent frequency of the sensor is adjusted, the effective frequency band of the sensor in a low-frequency range is expanded, the stress concentration is avoided, the anti-fatigue capability of the structure is enhanced, and the service life of the sensor is prolonged; the sensitivity of the sensor is improved, tiny vibration signals can be amplified, high-load large-acceleration vibration signals can be detected, and the sensor can be used as a high-load acceleration sensor for automobiles and aerospace crafts.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber grating sensors, and particularly relates to a fiber grating accelerometer. Background Art

[0002] With the continuous development of modern engineering technologies, the demand for accelerometers is increasing day by day, especially for accurate measurements with large accelerations and large dynamic ranges in automotive safety, aerospace, and national defense security. Traditional accelerometers, especially those based on capacitance, piezoelectric, or MEMS technologies, often face some technical problems to be solved when dealing with large accelerations, such as nonlinear response, saturation effect, temperature drift, and electromagnetic interference.

[0003] Accelerometers using fiber grating technology have a series of unique technical advantages. The fiber grating accelerometer, as a "passive device", has the characteristics of simple structure, small size, high temperature and high pressure resistance, corrosion resistance, electromagnetic interference resistance, and the ability to achieve distributed detection. It can provide a relatively wide dynamic detection range. Especially when facing large accelerations, it can maintain a good linear response. The fiber grating sensor can linearly respond to the change of acceleration by measuring the wavelength change of the Bragg grating, avoiding the technical problems of saturation effect and nonlinear response. Currently reported fiber grating large accelerometers generally have technical problems of limited dynamic range and coupling between the sensor and the mechanical structure. One is that the increase in the acceleration value exceeds the change range of the spectrum, resulting in signal saturation or distortion, and the dynamic range of the sensor needs to be improved. The other is that the fiber grating usually needs to be coupled with the mechanical structure. When the fiber grating is not stably installed or the mechanical structure has elastic deformation, additional errors will be introduced. Therefore, the existing technical methods need to be improved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned disadvantages of the existing fiber grating accelerometers, and provide a fiber grating high-load accelerometer with simple structure, high sensitivity, good accuracy and stability, high integration level, and long service life.

[0005] The technical solution adopted to solve the above technical problem is: a base is provided with a substrate, and a fiber grating is provided on the substrate. The grating region length of the fiber grating is 10 mm, and the wavelength is 1510 - 1565 nm. The substrate is in a cylindrical or elliptical cylindrical shape. A circular groove is machined in a plane perpendicular to the center line on the outer surface of the substrate, and the fiber grating is arranged in the groove. Two connection holes are radially machined at the lower end of the substrate, and sensitivity-enhancing holes are radially symmetrically machined on both sides of the connection holes.

[0006] In the present invention, a circular groove is machined in a plane perpendicular to the center line on the outer surface of the substrate, and the groove is a rectangular groove or an arc-shaped groove.

[0007] The groove width of the described rectangular groove is 0.2 - 0.3 mm, and the groove depth is 0.2 - 0.3 mm. The groove width and groove depth of the described arc-shaped groove are the same as those of the rectangular groove. The horizontal cross-section of the arc-shaped groove is an arc line, and the central angle subtended by the arc is 120° - 180°.

[0008] The cross-section of the described cylindrical body is an annular shape. The width of the cylindrical body is 20 - 40 mm, the outer diameter is 40 - 80 mm, and the wall thickness is 1.5 - 2.5 mm. There are 2 - 6 columns of sensitizing holes on one side of the connecting hole, and 2 - 6 columns of sensitizing holes on the other side. Each column of sensitizing holes has 2 - 6 even numbers.

[0009] The cross-section of the described elliptical cylindrical body is an elliptical annular shape. The major axis b of the inner ellipse is 70 - 90 mm, the minor axis c is 30 - 60 mm, and the wall thickness is 1.5 - 2.5 mm. Two connecting holes are radially processed at the lower end of the minor axis c of the elliptical ring. Sensitizing holes are radially symmetrically processed on both sides of the connecting holes. There are 2 - 6 columns of sensitizing holes on one side, and 2 - 6 columns of sensitizing holes on the other side. Each column of sensitizing holes has 2 - 6 even numbers.

[0010] The aperture of the described sensitizing hole is 1.0 mm - 1.4 mm, and the center distance between one sensitizing hole in a column and the sensitizing hole in the same row of the adjacent column is 3 mm - 4.6 mm.

[0011] The described substrate is a magnesium-aluminum alloy substrate.

[0012] The shape of the described base is a rectangular body.

[0013] The length of the described base is 60 - 120 mm, the width is 10 - 30 mm, and the height is 20 - 40 mm.

[0014] The beneficial effects of the present invention are as follows:

[0015] Since the sensing element of the present invention uses a fiber Bragg grating and the substrate adopts a hollow cylindrical or elliptical cylindrical structure, and the substrate is made of a magnesium alloy material, the weight of the sensor is reduced and the strength of the sensor is improved. Sensitivity-enhancing holes are processed on the substrate, reducing the elastic strain, solving the disadvantages of the existing acceleration fiber Bragg grating sensors, such as low sensitivity and small detection range. Without changing the detection bandwidth, the natural frequency of the sensor is adjusted, making it more suitable for the detection requirements of low-frequency vibration. The lower stiffness expands the effective working frequency band of the sensor in the low-frequency range, improves the dynamic response performance, avoids the stress concentration phenomenon, enhances the anti-fatigue ability of the structure, extends the service life of the sensor, greatly improves the sensitivity of the sensor, can amplify tiny vibration signals, and realizes the detection of high-load large-acceleration vibration signals. The acceleration sensor with this structure has the advantages of simple structure, high reliability, good sensitivity, accuracy and stability, and can be used as a high-load acceleration sensor for automobiles and aerospace aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. 3 is a schematic structural diagram of Embodiment 1 of the present invention.

[0017] Figure 2 FIG. Figure 1 is a top view of FIG.

[0018] Figure 3 FIG. Figure 1 is a sorting diagram of the sensitivity-enhancing holes 5 on the cylindrical substrate 1 in FIG.

[0019] Figure 4 FIG. is a strain curve for fiber Bragg gratings 3 with different inner diameters of the cylindrical substrate 1.

[0020] Figure 5 FIG. is a strain curve for fiber Bragg gratings 3 with different thicknesses of the cylindrical substrate 1. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be further described in detail below with reference to the drawings and embodiments, but the present invention is not limited to the following embodiments.

[0022] Embodiment 1

[0023] Figure 1 , 2 , FIGS. 3 show a schematic structural diagram of the fiber Bragg grating high-load acceleration sensor of this embodiment. In FIGS. Figure 1 , 2 , 3, the fiber Bragg grating high-load acceleration sensor of this embodiment is composed of a substrate 1, a base 2, and a fiber Bragg grating 3 connected together.

[0024] The base 1 is fixedly connected to the base 2 by threaded fastening connectors. The base 1 is made of magnesium alloy material and is formed into a cylindrical shape by one-time casting. The width of the base 1 is 20 - 40 mm, the outer diameter is 40 - 80 mm, and the wall thickness is 1.5 - 2.5 mm. In this embodiment, the width of the base 1 is 30 mm, the outer diameter is 60 mm, and the wall thickness is 2 mm. A rectangular groove is machined in a plane perpendicular to the center line on the outer surface of the base 1. The width of the rectangular groove is 0.2 - 0.3 mm, and the depth is 0.2 - 0.3 mm. In this embodiment, the width of the rectangular groove is 0.25 mm, and the depth is 0.25 mm. A fiber Bragg grating 3 is bonded to the bottom of the rectangular groove with epoxy adhesive. The grating region length of the fiber Bragg grating 3 is 10 mm, and the wavelength is 1510 - 1565 nm. In this embodiment, the grating region length of the fiber Bragg grating 3 is 10 mm, and the wavelength is 1550 nm. The base 1 is used to amplify the acceleration signal generated by external vibration and couple it to the fiber Bragg grating 3, and the detection of the external vibration acceleration signal by the sensor is realized by real-time monitoring of the change of the center wavelength of the fiber Bragg grating 3.

[0025] Two connection holes 4 are machined radially at the lower end of the base 1. The connection holes 4 are used to connect to the base 2 through threaded fastening connectors. Sensitivity-enhancing holes 5 are machined radially and symmetrically on both sides of the connection holes 4. There are 2 - 6 columns of sensitivity-enhancing holes 5 on one side of the connection hole 4, and 2 - 6 columns on the other side. Each column of sensitivity-enhancing holes 5 has 2 - 6 even numbers. In this embodiment, there are 4 columns of sensitivity-enhancing holes 5 on one side of the connection hole 4 and 4 columns on the other side. Each column of sensitivity-enhancing holes 5 has 4 holes. The aperture of the sensitivity-enhancing holes 5 is 1.0 mm - 1.4 mm. The center distance between a sensitivity-enhancing hole 5 in one column and the same-row sensitivity-enhancing hole 5 in the adjacent column is 3 mm - 4.6 mm. In this embodiment, the aperture of the sensitivity-enhancing holes 5 is 1.2 mm, and the center distance between a sensitivity-enhancing hole 5 in one column and the same-row sensitivity-enhancing hole 5 in the adjacent column is 3.8 mm.

[0026] Since the present invention adopts the machining of sensitivity-enhancing holes 5 on the base 1, the elastic strain is reduced, and the disadvantages of low sensitivity and small detection range of the existing acceleration fiber Bragg grating sensor are solved. Without changing the detection bandwidth, the natural frequency of the sensor is adjusted, which better meets the detection requirements of low-frequency vibration. The lower stiffness expands the effective working frequency band of the sensor in the low-frequency range, improves the dynamic response performance, avoids the stress concentration phenomenon, enhances the fatigue resistance of the structure, prolongs the service life of the sensor, greatly improves the sensitivity of the sensor, can amplify tiny vibration signals, and realizes the detection of high-load large-acceleration vibration signals.

[0027] The geometric shape of the base 2 is a rectangular body. The length of the base 2 is 60 - 120 mm, the width is 10 - 30 mm, and the height is 20 - 40 mm. In this embodiment, the length of the base 2 is 90 mm, the width is 20 mm, and the height is 30 mm.

[0028] Example 2

[0029] The substrate 1 of this example is made into a cylindrical shape by one-time casting of a magnesium-aluminum alloy material. The width of the substrate 1 is 20 - 40 mm, the outer diameter is 40 - 80 mm, and the wall thickness is 1.5 - 2.5 mm. In this example, the width of the substrate 1 is 20 mm, the outer diameter is 40 mm, and the wall thickness is 1.5 mm. A rectangular groove is machined in the plane perpendicular to the center line on the outer surface of the substrate 1. The groove width of the rectangular groove is 0.2 - 0.3 mm, and the groove depth is 0.2 - 0.3 mm. In this example, the groove width of the rectangular groove is 0.2 mm, and the groove depth is 0.2 mm. A fiber Bragg grating 3 is bonded at the bottom of the rectangular groove with an epoxy resin adhesive. The grating region length of the fiber Bragg grating 3 is 10 mm, and the wavelength is 1510 - 1565 nm. In this example, the grating region length of the fiber Bragg grating 3 is 10 mm, and the wavelength is 1510 nm.

[0030] Two connection holes 4 are machined radially at the lower end of the substrate 1. The connection holes 4 are used to connect with the base 2 through threaded fastening connectors. Sensitization holes 5 are machined radially symmetrically on both sides of the connection holes 4; there are 2 - 6 columns of sensitization holes 5 on one side of the connection hole 4, and 2 - 6 columns of sensitization holes 5 on the other side. Each column of sensitization holes 5 has 2 - 6 even numbers. In this example, there are 2 columns of sensitization holes 5 radially on one side of the connection hole 4, and 2 columns of sensitization holes 5 on the other side. Each column of sensitization holes 5 has 6. The aperture of the sensitization holes 5 is 1.0 mm - 1.4 mm. The center distance between a sensitization hole 5 in one column and the sensitization hole 5 in the same row of the adjacent column is 3 mm - 4.6 mm. In this example, the aperture of the sensitization holes 5 is 1.0 mm, and the center distance between a sensitization hole 5 in one column and the sensitization hole 5 in the same row of the adjacent column is 4.6 mm.

[0031] The geometric shape of the base 2 is a rectangular parallelepiped. The length of the base 2 is 60 - 120 mm, the width is 10 - 30 mm, and the height is 20 - 40 mm. In this example, the length of the base 2 is 60 mm, the width is 10 mm, and the height is 20 mm.

[0032] Other components and the connection relationships of the components are the same as those in Example 1.

[0033] Example 3

[0034] The substrate 1 of this embodiment is formed into a cylindrical shape by one-time casting of a magnesium-aluminum alloy material. The width of the substrate 1 is 20 - 40 mm, the outer diameter is 40 - 80 mm, and the wall thickness is 1.5 - 2.5 mm. In this embodiment, the width of the substrate 1 is 40 mm, the outer diameter is 80 mm, and the wall thickness is 2.5 mm. A rectangular groove is machined in a plane perpendicular to the center line on the outer surface of the substrate 1. The groove width of the rectangular groove is 0.2 - 0.3 mm, and the groove depth is 0.2 - 0.3 mm. In this embodiment, the groove width of the rectangular groove is 0.3 mm, and the groove depth is 0.3 mm. A fiber Bragg grating 3 is bonded to the bottom of the rectangular groove with an epoxy resin adhesive. The grating region length of the fiber Bragg grating 3 is 10 mm, and the wavelength is 1510 - 1565 nm. In this embodiment, the grating region length of the grating 3 is 10 mm, and the wavelength is 1565 nm.

[0035] Two connection holes 4 are machined radially at the lower end of the substrate 1. The connection holes 4 are used to connect with the base 2 through threaded fastening connectors. Sensitization holes 5 are machined radially and symmetrically on both sides of the connection holes 4. There are 2 - 6 columns of sensitization holes 5 on one side of the connection hole 4, and 2 - 6 columns of sensitization holes 5 on the other side. Each column of sensitization holes 5 has 2 - 6 even numbers. In this embodiment, there are 6 columns of sensitization holes 5 radially on one side of the connection hole 4, and 6 columns of sensitization holes 5 radially on the other side. Each column of sensitization holes 5 has 2. The aperture of the sensitization holes 5 is 1.0 mm - 1.4 mm. The center distance between one sensitization hole 5 in a column and the sensitization hole 5 in the same row of the adjacent column is 3 mm - 4.6 mm. In this embodiment, the aperture of the sensitization holes 5 is 1.4 mm, and the center distance between one sensitization hole 5 in a column and the sensitization hole 5 in the same row of the adjacent column is 3 mm.

[0036] The geometric shape of the base 2 is a rectangular parallelepiped. The length of the base 2 is 60 - 120 mm, the width is 10 - 30 mm, and the height is 20 - 40 mm. In this embodiment, the length of the base 2 is 120 mm, the width is 30 mm, and the height is 40 mm.

[0037] Other components and the connection relationships of the components are the same as those in Embodiment 1.

[0038] Embodiment 4

[0039] In the above Embodiments 1 - 3 of this invention, the substrate 1 is formed into a cylindrical shape by one-time casting of a magnesium-aluminum alloy material. The cross-section of the cylinder is an annular shape. The geometric dimensions of the substrate 1 are the same as those of the corresponding embodiments. An arc-shaped groove is machined in a plane perpendicular to the center line on the outer surface of the substrate 1. The horizontal section of the arc-shaped groove is an arc line. The central angle subtended by the arc is 120° - 180°. In this embodiment, the central angle subtended by the arc is 150°.

[0040] On the right end of the base 1, two connecting holes 4 are radially machined. On both sides of the connecting holes 4, sensitivity enhancing holes 5 are symmetrically machined in the radial direction. The arrangement order, quantity, aperture diameter of the sensitivity enhancing holes 5, and the center distance between one sensitivity enhancing hole 5 in one column and the sensitivity enhancing hole 5 in the same row of the adjacent column are the same as those in the corresponding embodiment.

[0041] The geometric shape and geometric dimensions of the base 2 are the same as those in the corresponding embodiment.

[0042] Other components and the connection relationships of the components are the same as those in Embodiment 1.

[0043] Embodiment 5

[0044] In the above Embodiments 1 to 3 of the present invention, the base 1 is made of magnesium alloy material and formed into a cylindrical shape by one-time casting. The cross-section of the cylinder is an annular shape. The geometric dimensions of the base 1 are the same as those in the corresponding embodiment. A circular arc-shaped groove is machined in the plane perpendicular to the center line on the outer surface of the base 1. The groove width and groove depth of the circular arc-shaped groove are the same as those in the corresponding embodiment. The horizontal cross-section of the circular arc-shaped groove is an arc line, and the central angle subtended by the arc is 120° - 180°. In this embodiment, the central angle subtended by the arc is 120°.

[0045] On the right end of the base 1, two connecting holes 4 are radially machined. On both sides of the connecting holes 4, sensitivity enhancing holes 5 are symmetrically machined in the radial direction. The arrangement order, quantity, aperture diameter of the sensitivity enhancing holes 5, and the center distance between one sensitivity enhancing hole 5 in one column and the sensitivity enhancing hole 5 in the same row of the adjacent column are the same as those in the corresponding embodiment.

[0046] The geometric shape and geometric dimensions of the base 2 are the same as those in the corresponding embodiment.

[0047] Other components and the connection relationships of the components are the same as those in Embodiment 1.

[0048] Embodiment 6

[0049] In the above Embodiments 1 to 3 of the present invention, the base 1 is made of magnesium alloy material and formed into a cylindrical shape by one-time casting. The cross-section of the cylinder is an annular shape. The geometric dimensions of the base 1 are the same as those in the corresponding embodiment. A circular arc-shaped groove is machined in the plane perpendicular to the center line on the outer surface of the base 1. The groove width and groove depth of the circular arc-shaped groove are the same as those in the corresponding embodiment. The horizontal cross-section of the circular arc-shaped groove is an arc line, and the central angle subtended by the arc is 120° - 180°. In this embodiment, the central angle subtended by the arc is 180°.

[0050] On the right end of the base 1, two connecting holes 4 are radially machined. On both sides of the connecting holes 4, sensitivity enhancing holes 5 are symmetrically machined in the radial direction. The arrangement order, quantity, aperture diameter of the sensitivity enhancing holes 5, and the center distance between one sensitivity enhancing hole 5 in one column and the sensitivity enhancing hole 5 in the same row of the adjacent column are the same as those in the corresponding embodiment.

[0051] The geometric shape and geometric dimensions of the base 2 are the same as those of the corresponding embodiment.

[0052] The other components and the connection relationships between the components are the same as those in Embodiment 1.

[0053] Embodiment 7

[0054] In the above Embodiments 1 to 6, the base 1 is made of magnesium alloy material by one-time casting into an elliptical cylindrical shape. The vertical cross-section of the elliptical cylinder is an elliptical ring. The major axis b of the inner ellipse is 70 - 90 mm, the minor axis c is 30 - 60 mm, and the wall thickness is 1.5 - 2.5 mm. In this embodiment, the major axis b of the inner ellipse is 80 mm, the minor axis c is 45 mm, and the wall thickness is 2 mm.

[0055] Two connection holes 4 are radially machined at the lower end of the minor axis c of the elliptical ring. Sensitivity-enhancing holes 5 are radially symmetrically machined on both sides of the connection holes 4. The arrangement order, quantity, hole diameter of the sensitivity-enhancing holes 5, and the center distance between a sensitivity-enhancing hole 5 in one row and the sensitivity-enhancing hole 5 in the same row of the adjacent row are the same as those of the corresponding embodiment.

[0056] The geometric shape and geometric dimensions of the base 2 are the same as those of the corresponding embodiment.

[0057] The other components and the connection relationships between the components are the same as those in Embodiment 1.

[0058] Embodiment 8

[0059] In the above Embodiments 1 to 6, the base 1 is made of magnesium alloy material by one-time casting into an elliptical cylindrical shape. The vertical cross-section of the elliptical cylinder is an elliptical ring. The major axis b of the inner ellipse is 70 - 90 mm, the minor axis c is 30 - 60 mm, and the wall thickness is 1.5 - 2.5 mm. In this embodiment, the major axis b of the inner ellipse is 70 mm, the minor axis c is 30 mm, and the wall thickness is 1.5 mm.

[0060] Two connection holes 4 are radially machined at the lower end of the minor axis c of the elliptical ring. Sensitivity-enhancing holes 5 are radially symmetrically machined on both sides of the connection holes 4. The arrangement order, quantity, hole diameter of the sensitivity-enhancing holes 5, and the center distance between a sensitivity-enhancing hole 5 in one row and the sensitivity-enhancing hole 5 in the same row of the adjacent row are the same as those of the corresponding embodiment.

[0061] The geometric shape and geometric dimensions of the base 2 are the same as those of the corresponding embodiment.

[0062] The other components and the connection relationships between the components are the same as those in Embodiment 1.

[0063] Embodiment 9

[0064] In the above Examples 1 to 6, the base 1 is made of a magnesium-aluminum alloy material by one-time casting into an elliptical cylindrical shape. The vertical cross-section of the elliptical cylinder is an elliptical ring. The major axis b of the inner ellipse is 70 - 90 mm, the minor axis c is 30 - 60 mm, and the wall thickness is 1.5 - 2.5 mm. In this example, the major axis b of the inner ellipse is 90 mm, the minor axis c is 60 mm, and the wall thickness is 2 mm.

[0065] Two connection holes 4 are radially machined at the lower end of the minor axis c of the elliptical ring. Sensitizing holes 5 are radially symmetrically machined on both sides of the connection holes 4. The arrangement order, quantity, hole diameter of the sensitizing holes 5, and the center distance between a sensitizing hole 5 in one row and the same-row sensitizing hole 5 in the adjacent row are the same as those in the corresponding example.

[0066] The geometric shape and geometric dimensions of the base 2 are the same as those in the corresponding example.

[0067] Other components and the connection relationships of the components are the same as those in Example 1.

[0068] In order to determine the optimal parameters of the present invention and verify the beneficial effects of the present invention, the inventor has conducted a large number of laboratory research experiments. The various experimental situations are as follows:

[0069] 1. Determine the inner diameter of the cylindrical base

[0070] Using the fiber Bragg grating high-load acceleration sensor of Example 1, the vibration frequency is set to 100 Hz, and the acceleration is 4900 m / s 2 , the strain results at three locations of the fiber Bragg grating of the cylindrical body with different inner diameters are as Figure 4 shown. As Figure 4 can be seen, as the inner diameter of the cylindrical structure increases, the strain on the fiber structure caused by vibration at 4900 m / s 2 acceleration also increases, and the sensitivity also increases relatively. To ensure the structural stability and that the fiber Bragg grating 3 does not break, the outer diameter of the cylindrical structure is therefore selected to be 40 - 80 mm.

[0071] 2. Determine the thickness of the cylindrical base

[0072] Using the fiber Bragg grating high-load acceleration sensor of Example 1, the vibration frequency is set to 100 Hz, and the acceleration is 4900 m / s 2 , the strain results at three locations of the fiber Bragg grating of the cylindrical body with different thicknesses are as Figure 5 shown. As Figure 5 can be seen, as the wall thickness of the cylinder continuously increases, the strain on the structure caused by the same acceleration vibration decreases, and the sensitivity also decreases accordingly. When the wall thickness reaches 4 mm, it approaches 0. Therefore, the wall thickness is selected to be 1.5 - 2.5 mm.

[0073] 3. Use the fiber Bragg grating high-load acceleration sensor of Embodiment 1, set the vibration frequency to 100 Hz, and the acceleration to 4900 m / s 2 , and calculate the sensitivity S of the acceleration sensor according to Equation (1):

[0074]

[0075] Δλ B =λ B ×(1 - ρ e )×ε

[0076]

[0077] m=ρv

[0078] A=n(R 2 - r 2 )

[0079]

[0080] where, Δλ B represents the Bragg wavelength drift of fiber Bragg grating 3, λ B represents the initial Bragg wavelength of fiber Bragg grating 3, ε represents the applied strain, a represents the acceleration, ρ e represents the strain-optic coefficient of the strained fiber Bragg grating 3, with a value of 0.22, m represents the mass of the substrate 1; E represents the elastic modulus of the material of the substrate 1, with a value of 72 GPa, A is the cross-sectional area of the substrate 1, R represents the outer diameter of the cylinder, r represents the inner diameter of the cylinder, ρ is the density of the material of the substrate 1, ρ has a value of 1800 kg / m3, v is the volume, K is the sensitivity enhancement factor, with a value of 2.5, D is the outer diameter of the sensitizing hole 5, n is the number of columns of the sensitizing hole 5, and d is the center-to-center distance of the sensitizing hole 5.

[0081] The sensitivity S calculated according to Equation (1) is 0.227 pm / g.

[0082] According to the above principle, another fiber Bragg grating high-load acceleration sensor with a specific structure can also be designed, but all are within the scope of the claims of the present invention.

Claims

1. A fiber Bragg grating high-load acceleration sensor, wherein a base (1) is arranged on a base (2), a fiber Bragg grating (3) is arranged on the base (1), the grating area length of the fiber Bragg grating (3) is 10 mm, and the wavelength is 1510-1565 nm, characterized in that: The substrate (1) is cylindrical or elliptical, and a circle of grooves is processed in a plane perpendicular to the center line of the outer surface of the substrate (1). The optical fiber grating (3) is arranged in the groove. Two connecting holes (4) are radially processed at the lower end of the substrate (1), and sensitivity enhancement holes (5) are radially symmetrically processed on both sides of the connecting holes.

2. The fiber Bragg grating high load acceleration sensor according to claim 1, characterized in that: The groove is a rectangular groove or an arc-shaped groove.

3. The fiber Bragg grating high load acceleration sensor according to claim 2, characterized in that: The rectangular groove has a groove width of 0.2-0.3 mm and a groove depth of 0.2-0.3 mm; the groove width and groove depth of the arc-shaped groove are the same as those of the rectangular groove, and the horizontal section of the arc-shaped groove is an arc line, and the central angle of the arc is 120°-180°.

4. The fiber Bragg grating high load acceleration sensor according to claim 1, characterized in that The cross section of the cylinder is annular, the width of the cylinder is 20 to 40 mm, the outer diameter is 40 to 80 mm, and the wall thickness is 1.5 to 2.5 mm; there are 2 to 6 rows of sensitivity holes (5) on one side of the connecting hole (4), and 2 to 6 rows of sensitivity holes (5) on the other side, and each row of sensitivity holes (5) has an even number of 2 to 6.

5. The fiber Bragg grating high load acceleration sensor according to claim 1, characterized in that: The cross section of the elliptical cylinder is an elliptical ring, the major axis b of the inner ellipse is 70 to 90 mm, the minor axis c is 30 to 60 mm, and the wall thickness is 1.5 to 2.5 mm. Two connecting holes (4) are radially processed at the lower end of the minor axis c of the elliptical ring, and sensitivity holes (5) are radially symmetrically processed on both sides of the connecting holes (4). There are 2 to 6 rows of sensitivity holes (5) on one side and 2 to 6 rows of sensitivity holes (5) on the other side, and each row of sensitivity holes (5) has an even number of 2 to 6.

6. The fiber Bragg grating high load acceleration sensor according to claim 1, 4 or 5, characterized in that: The aperture of the sensitivity enhancement hole (5) is 1.0 mm to 1.4 mm, and the hole center distance between a sensitivity enhancement hole (5) in one column and a sensitivity enhancement hole (5) in the same row of an adjacent column is 3 mm to 4.6 mm.

7. The fiber Bragg grating high load acceleration sensor according to claim 1, characterized in that: The substrate (1) is a magnesium-aluminum alloy substrate.

8. The fiber Bragg grating high load acceleration sensor according to claim 1, characterized in that: The base (2) is in the shape of a rectangular body.

9. The fiber Bragg grating high load acceleration sensor according to claim 8, characterized in that: The base (2) has a length of 60 to 120 mm, a width of 10 to 30 mm, and a height of 20 to 40 mm.

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