Sand load measuring device and measuring method

Abstract

The invention discloses a sand load measuring device and a measuring method. The device comprises a base; the supporting rod is vertically arranged on the base; the sand load input module is used for applying sand load to the angle steel test piece; the two ends of the sliding adjusting module are connected to the supporting rod and the sand load input module correspondingly, and the sliding adjusting module can slide up and down along the supporting rod and is used for adjusting the height of the sand load input module; the test piece fixing module is arranged on the base and used for fixing the angle steel test piece under the sand load input module and adjusting the constraint condition of the angle steel test piece; a strain gauge is arranged in the test piece fixing module, and strain data collected by the strain gauge is used for calculating a sand load measurement value. The vibration frequency can be changed by adjusting the constraint condition of the angle steel, so that the sand load borne by the angle steel at different vibration frequencies can be measured.

Description

Technical Field

[0001] The invention relates to the technical field of transmission tower structure monitoring, and in particular to a sand load measuring device and a measuring method. Background Art

[0002] In areas with frequent droughts and sandstorms, transmission towers are exposed to complex sandstorm environments for a long time and are significantly affected by sandstorm loads. The sandstorm effect not only includes the load generated by wind, but also carries high-speed sand particles to impact the surface of the transmission tower structure. The sandstorm impact may aggravate the wear of the metal surface and affect the strength and life of the transmission tower. The main material of the transmission tower is angle steel, so it is necessary to measure the load of sand particles on the angle steel of the transmission tower to quantitatively analyze the safety of the transmission tower structure under sandstorm loads.

[0003] However, there is no research on the sand load on the angle steel, a main component of the transmission tower, in the prior art, and therefore a sand load measuring device and method are urgently needed. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a sand load measuring device and a measuring method, which can change the vibration frequency by adjusting the constraint conditions of the angle steel, thereby realizing the measurement of the sand load on the angle steel at different vibration frequencies.

[0005] An embodiment of the present invention provides a sand load measuring device, comprising:

[0006] Base;

[0007] A support rod is vertically arranged on the base;

[0008] Sand load input module, used to apply sand load to angle steel specimens;

[0009] A sliding adjustment module, the two ends of which are respectively connected to the support rod and the sand load input module, and can slide up and down along the support rod to adjust the height of the sand load input module;

[0010] A specimen fixing module is arranged on the base, and is used to fix the angle steel specimen directly below the sand load input module, and to adjust the constraint conditions of the angle steel specimen; a strain gauge is arranged in the specimen fixing module, and the strain data collected by the strain gauge is used to calculate the sand load measurement value.

[0011] Furthermore, the sand load measuring device also includes:

[0012] The acceleration sensor is used to measure the acceleration of the angle steel specimen to obtain the vibration frequency of the angle steel specimen according to the acceleration of the angle steel specimen.

[0013] Furthermore, the sliding adjustment module comprises: a crossbar, a ring, a fixing screw and a fastener, and two ends of the crossbar are respectively connected to the ring and the fastener;

[0014] The sliding adjustment module is fixed to the support rod through the annular member and the fixing screws; and the sand load input module is fixed to the sliding adjustment module through the fasteners.

[0015] Furthermore, protrusion structures are respectively provided on both sides of the base, and through holes are provided on the protrusion structures, and the specimen fixing module is connected to the base via screws provided in the through holes;

[0016] The specimen fixing module includes: two fixing rods respectively located on both sides of the angle steel specimen, screws in the two through holes and a tension knob located at the head of the screw; one end of the fixing rod away from the angle steel specimen is connected to the tail of the screw in the through hole located on the corresponding side; the tension knob is used to adjust the tightness of the fixing rod clamping the angle steel specimen.

[0017] Furthermore, the fixing rod is an elastic member;

[0018] The strain gauge is arranged on the central axis of each of the fixing rods and is used to measure the strain value of the fixing rod.

[0019] Further, the sand load input module is a funnel;

[0020] The acceleration sensor adopts a capacitive MEMS acceleration sensor, and the acceleration sensor is attached to the angle steel specimen.

[0021] The embodiment of the present invention further provides a sand load measurement method, which is applied to the above-mentioned sand load measurement device. The sand load measurement method includes:

[0022] Fixing the angle steel specimen on the specimen fixing module, and adjusting the magnitude of the restraining force applied to the angle steel specimen through the specimen fixing module, so that the angle steel specimen is under a preset restraining condition;

[0023] Measuring a first resistance of the strain gauge, and calculating a first strain value according to the first resistance;

[0024] Adjust the sliding adjustment module to the preset height;

[0025] A preset amount of sand is placed in a sand load input module, and the sand load input module applies a sand load to the angle steel specimen;

[0026] When the sand load is applied, the acceleration of the angle steel specimen is measured by an acceleration sensor, and the vibration frequency of the angle steel specimen is obtained according to the acceleration of the angle steel specimen;

[0027] When applying the sand load, measuring the second resistance of the strain gauge, and calculating the second strain value according to the second resistance;

[0028] The magnitude of the sand load on the angle steel specimen is calculated based on the first strain value and the second strain value.

[0029] Furthermore, the sand load measurement method further includes:

[0030] By adjusting the specimen fixing module, the constraint condition of the angle steel specimen is changed to change the vibration frequency of the angle steel specimen;

[0031] By measuring the strain value of the strain gauge under different constraint conditions, the sand load on the angle steel specimen at different vibration frequencies is obtained.

[0032] Further, obtaining the vibration frequency of the angle steel specimen according to the acceleration of the angle steel specimen comprises:

[0033] According to the acceleration of the angle steel specimen, a discrete Fourier transform method is used to obtain the acceleration spectrum;

[0034] The frequency corresponding to the spectrum peak of the spectrum is obtained to obtain the vibration frequency of the angle steel specimen.

[0035] Further, the sand load on the angle steel specimen is calculated based on the first strain value and the second strain value, including:

[0036] Calculating a strain difference value according to the first strain value and the second strain value;

[0037] Based on the strain difference, the stress is calculated according to the Young's modulus expression;

[0038] Based on the stress and according to the relationship between stress and force, the sand load on the angle steel specimen is calculated.

[0039] Compared with the prior art, the beneficial effect of a sand load measurement device and measurement method provided by the embodiment of the present invention is that by setting a base, a support rod, a sliding adjustment module, a sand load input module and a specimen fixing module, the constraint conditions of the angle steel specimen can be adjusted, and the sand load measurement value can be obtained through the strain gauge set in the specimen fixing module, so as to realize the load research of the transmission tower angle steel specimen under the controllable elastic support boundary, and solve the problem of low universality of the existing load measurement device. The embodiment of the present invention can use this device to simulate different constraint conditions according to the constraint conditions of the angle steel under different transmission tower design standards, and can also simulate the sand load conditions in different regional working environments by controlling the sand input amount, and simulate the sand load conditions at different speeds by adjusting the height of the sand load input device. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a structural schematic diagram of a sand load measuring device provided by an embodiment of the present invention;

[0041] Figure 2 is a top view of a sand load measuring device provided by an embodiment of the present invention;

[0042] Figure 3 It is a structural schematic diagram of a specimen fixing module in a sand load measuring device provided by an embodiment of the present invention;

[0043] Figure 4 It is a structural schematic diagram of an angle steel specimen provided by an embodiment of the present invention;

[0044] Figure 5 is a flow chart of a sand load measurement method provided by an embodiment of the present invention;

[0045] The reference numerals are as follows:

[0046] 1. Sand load input module; 2. Support rod; 3. Base; 4. Specimen fixing module; 5. Sliding adjustment module; 6. Strain gauge; 7. Angle steel specimen; 8. Acceleration sensor; 9. Fixing rod; 10. Tension knob. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the transmission tower structure, the rods need to be connected to the node plates, and different constraints will cause different rod frequencies, which are the same as the vibration frequency of the angle steel under load. The frequency is determined by the constraints and is not affected by the load; but conversely, the constraints will affect the frequency and further affect the size of the sand load on the rod. Therefore, in order to study the load conditions of the angle steel under different constraints, an embodiment of the present invention provides a sand load measurement device with adjustable constraint effects, which can change the rod frequency by adjusting the constraints, and then measure the size of the sand load on the rod when the rod frequency is different.

[0049] See also Figure 1 , Figure 1 1 is a schematic diagram of the structure of a sand load measuring device provided by an embodiment of the present invention. The sand load measuring device comprises:

[0050] Base 3;

[0051] A support rod 2 is vertically arranged on the base 3;

[0052] A sand load input module 1 is used to apply a sand load to the angle steel specimen 7;

[0053] A sliding adjustment module 5, both ends of which are respectively connected to the support rod 2 and the sand load input module 1, and can slide up and down along the support rod 2 to adjust the height of the sand load input module 1;

[0054] The specimen fixing module 4 is arranged on the base 3, and is used to fix the angle steel specimen 7 directly below the sand load input module 1, and to adjust the constraint conditions of the angle steel specimen 7; the specimen fixing module 4 is provided with a strain gauge 6, and the strain data collected by the strain gauge 6 is used to calculate the sand load measurement value.

[0055] Specifically, the base 3 is the carrier of the entire device, and is provided with a card slot and connected to the support rod 2 through the card slot. Two rectangular shaped protruding structures are also provided on both sides of the base 3. A through hole is opened on the side of each protruding structure, and the through hole is preferably set as a screw hole.

[0056] The support rod 2 connects the base 3 and the sliding adjustment module 5, and is a column with a square cross-section and rounded corners on all sides.

[0057] Furthermore, the sliding adjustment module 5 includes: a crossbar, a ring, a fixing screw and a fastener, and the two ends of the crossbar are respectively connected to the ring and the fastener;

[0058] The sliding adjustment module 5 is fixed to the support rod 2 through the annular member and the fixing screws; the sand load input module 1 is fixed to the sliding adjustment module 5 through the fasteners.

[0059] See also Figure 2 , Figure 2 1 is a top view of a sand load measuring device provided by an embodiment of the present invention.

[0060] Specifically, the sliding adjustment module 5 is connected to the support rod 2 through a square-section ring member, and is fixed to the support rod 2 through fixing screws on the ring member to fix the position of the sand load input module 1, ensuring that the sand can fall on the expected position of the angle steel specimen 7. At the same time, by loosening the fixing screws, the height of the sand load input module 1 can be adjusted by sliding up and down to control the speed of the sand during the experiment.

[0061] Furthermore, the sand load input module 1 is a funnel.

[0062] During the experiment, sand is put into the funnel, and the sand load can be applied to the angle steel specimen 7 under the funnel.

[0063] Furthermore, protrusion structures are respectively provided on both sides of the base 3, and through holes are provided on the protrusion structures. The specimen fixing module 4 is connected to the base 3 via screws provided in the through holes.

[0064] The specimen fixing module 4 includes: two fixing rods 9 respectively located on both sides of the angle steel specimen 7, screws in the two through holes and a tension knob 10 located at the head of the screw; one end of the fixing rod 9 away from the angle steel specimen 7 is connected to the tail of the screw in the through hole located on the corresponding side; the tension knob 10 is used to adjust the tightness of the fixing rod 9 clamping the angle steel specimen 7.

[0065] Furthermore, the fixing rod 9 is an elastic member;

[0066] The strain gauge 6 is disposed on the central axis of each of the fixing rods 9 and is used to measure the strain value of the fixing rod 9 .

[0067] See also Figure 3 and Figure 4 , Figure 3 is a structural schematic diagram of a specimen fixing module in a sand load measuring device provided by an embodiment of the present invention, Figure 4 It is a structural schematic diagram of an angle steel specimen provided in an embodiment of the present invention.

[0068] Specifically, the specimen fixing module 4 is installed on the base 3, and the fixing rod 9 of the angle steel specimen is welded on the screws, and connected to the base 3 through the screws. The fixing rods 9 on both sides can clamp the angle steel specimen 7 to fix it in the middle. The fixing rod 9 is an elastic support, and an elastic member that is not prone to instability is selected; the tension knob 10 is star-shaped for easy operation.

[0069] Furthermore, strain gauges 6 are attached to the two fixing rods 9, which can measure the tightness of the constraint of the specimen fixing module 4 on the angle steel specimen 7. The larger the strain value corresponding to the strain gauge 6, the tighter the constraint. Different tightness means different constraint conditions. Under different constraint conditions, the angle steel and the fixing rod will have different vibration frequencies.

[0070] Furthermore, the sand load measuring device also includes:

[0071] The acceleration sensor 8 is used to measure the acceleration of the angle steel specimen 7 to obtain the vibration frequency of the angle steel specimen 7 according to the acceleration of the angle steel specimen 7.

[0072] Furthermore, the acceleration sensor 8 is a capacitive MEMS acceleration sensor, and the acceleration sensor 8 is attached to the angle steel specimen 7 .

[0073] The embodiment of the present invention can adjust the constraint conditions of the angle steel specimen by setting a base, a support rod, a sliding adjustment module, a sand load input module and a specimen fixing module, and obtain the sand load measurement value through the strain gauge set in the specimen fixing module, thereby realizing the load research of the transmission tower angle steel specimen under the controllable elastic support boundary, and solving the problem of low universality of the existing load measurement device. The embodiment of the present invention can use this device to simulate different constraint conditions according to the constraint conditions of the angle steel under different transmission tower design standards, and can also simulate the sand load conditions in different regional working environments by controlling the sand input amount, and simulate the sand load conditions at different speeds by adjusting the height of the sand load input device.

[0074] Accordingly, the present invention also provides a sand load measurement method, which is applied to the above-mentioned sand load measurement device. Figure 5 , Figure 5 1 is a flow chart of a sand load measurement method provided by an embodiment of the present invention. The sand load measurement method comprises:

[0075] S1: fixing the angle steel specimen 7 on the specimen fixing module 4, and adjusting the constraint force applied to the angle steel specimen 7 through the specimen fixing module 4, so that the angle steel specimen 7 is under a preset constraint condition;

[0076] Specifically, the angle steel specimen 7 is fixed between the two fixing rods 9 by means of the tension knob 10. When the tension knob 10 is gradually tightened, the restraining force on the angle steel specimen 7 gradually increases, and the corresponding force received by the fixing rod 9 also gradually increases. In this process, the fixing rod 9 undergoes compression deformation, becomes wider and shorter, and this deformation causes the terminal resistance of the strain gauge 6 to decrease. The strain value can be calculated by measuring the resistance of the strain gauge 6, and then the restraining force applied by the fixing rod 9 to the angle steel specimen 7 can be obtained. When conducting an experiment, the restraining force on the angle steel specimen 7 can be adjusted to the preset restraining conditions by means of the tension knob 10 to achieve quantitative research.

[0077] Among them, the elastic modulus E, strain value ε, and cross-sectional area A of the fixing rod 9 are obtained. From the Young's modulus expression E=σ / ε and the relationship between stress and force σ=F / A, the constraint force F applied by the fixing rod 9 to the angle steel specimen 7 can be obtained.

[0078] S2: measuring a first resistance of the strain gauge 6, and calculating a first strain value according to the first resistance;

[0079] Specifically, before applying the sand load, the first strain value ε1 of the strain gauge 6 is measured.

[0080] S3: Adjust the sliding adjustment module 5 to a preset height;

[0081] S4: putting a preset amount of sand into the sand load input module 1, and the sand load input module 1 applies sand load to the angle steel specimen 7;

[0082] Specifically, according to the sand content in different weather conditions, the amount of sand put into the sand load input module 1 is adjusted, and the sand speed is controlled to conduct sand load measurement experiments in different wind and sand environments. The sand speed is determined by the height of the sliding adjustment module 5. The higher the height, the faster the sand reaches the target, and the greater the sand load generated.

[0083] S5: When applying the sand load, the acceleration of the angle steel specimen 7 is measured by the acceleration sensor 8, and the vibration frequency of the angle steel specimen 7 is obtained according to the acceleration of the angle steel specimen 7;

[0084] Specifically, when the sand load input module 1 applies a sand load to the angle steel specimen 7, the angle steel specimen 7 generates acceleration. At the same time, the mass block in the capacitive MEMS acceleration sensor attached to the angle steel specimen 7 generates a small displacement due to the acceleration, thereby generating a change in differential capacitance, and then collecting the acceleration generated by the angle steel specimen 7 when the sand load is applied.

[0085] Further, obtaining the vibration frequency of the angle steel specimen 7 according to the acceleration of the angle steel specimen 7 includes:

[0086] According to the acceleration of the angle steel specimen 7, a discrete Fourier transform method is used to obtain the acceleration spectrum;

[0087] The frequency corresponding to the spectrum peak of the spectrum is obtained to obtain the vibration frequency of the angle steel specimen 7.

[0088] Specifically, after the actually measured acceleration data is converted into a spectrum, the frequency corresponding to the spectrum peak is the main vibration frequency of the angle steel, and the main vibration frequency is one of the indicators of structural safety monitoring.

[0089] It should be noted that the purpose of measuring acceleration is to determine whether the specimen fixing module 4 adjusts the vibration frequency of the angle steel specimen to the target value. For example, if the frequency of a certain angle steel specimen is determined to be 10 Hz according to the constraint conditions, then after adjusting the fixing rod 9 of the experimental device, the acceleration signal spectrum obtained by the acceleration sensor 8 should have a peak at the 10 Hz position. If it does not appear, the fixing rod 9 should be further adjusted until the frequency meets the requirements.

[0090] S6: When applying the sand load, measuring the second resistance of the strain gauge 6, and calculating a second strain value according to the second resistance;

[0091] Specifically, when the sand load is applied, the second strain value ε2 of the strain gauge 6 is measured and obtained.

[0092] S7: Calculate the sand load on the angle steel specimen 7 according to the first strain value and the second strain value.

[0093] Furthermore, the sand load magnitude of the angle steel specimen 7 is calculated based on the first strain value and the second strain value, including:

[0094] Calculating a strain difference value according to the first strain value and the second strain value;

[0095] Based on the strain difference, the stress is calculated according to the Young's modulus expression;

[0096] Based on the stress and according to the relationship between stress and force, the sand load on the angle steel specimen 7 is calculated.

[0097] Specifically, the calculation formula of the strain difference is: Δε=|ε2-ε1|, where Δε is the strain difference, ε1 is the strain value before applying the sand load; ε2 is the strain value when applying the sand load;

[0098] The elastic modulus E and cross-sectional area A of the fixing rod 9 are obtained, and the strain difference Δε is substituted into the Young's modulus expression to calculate the stress Δσ=E·Δε, and then the sand load ΔF=Δσ·A on the angle steel specimen 7 is calculated according to the relationship between stress and force.

[0099] Furthermore, the sand load measurement method further includes:

[0100] By adjusting the specimen fixing module 4, the constraint condition of the angle steel specimen 7 is changed to change the vibration frequency of the angle steel specimen 7;

[0101] By measuring the strain value of the strain gauge 6 under different constraint conditions, the sand load magnitude of the angle steel specimen 7 at different vibration frequencies is obtained.

[0102] Specifically, the constraint on the angle steel specimen 7 should be started from the most relaxed state, that is, the angle steel specimen 7 can just be constrained by the fixing rods 9 on both sides and will not fall. From this most relaxed state, the tension knob 10 should be gradually tightened to achieve different constraint conditions, and the vibration frequency under the constraint condition is determined by the acceleration sensor, and then the sand load size of the angle steel specimen at different vibration frequencies is measured.

[0103] The embodiment of the present invention can use the device to simulate different constraint conditions according to the constraint conditions of angle steel under different transmission tower design standards, and can also simulate the sand load conditions in working environments in different regions by controlling the sand input amount, and simulate the sand load conditions at different speeds by adjusting the height of the sand load input device.

[0104] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A sand load measuring device, characterized in that: include: Base; A support rod is vertically arranged on the base; Sand load input module, used to apply sand load to angle steel specimens; A sliding adjustment module, the two ends of which are respectively connected to the support rod and the sand load input module, and can slide up and down along the support rod to adjust the height of the sand load input module; A specimen fixing module is arranged on the base, and is used to fix the angle steel specimen directly below the sand load input module, and to adjust the constraint conditions of the angle steel specimen; a strain gauge is arranged in the specimen fixing module, and the strain data collected by the strain gauge is used to calculate the sand load measurement value.

2. The sand load measuring device according to claim 1, characterized in that: The sand load measuring device also includes: The acceleration sensor is used to measure the acceleration of the angle steel specimen to obtain the vibration frequency of the angle steel specimen according to the acceleration of the angle steel specimen.

3. The sand load measuring device according to claim 1, characterized in that: The sliding adjustment module comprises: a crossbar, a ring, a fixing screw and a fastener, and two ends of the crossbar are respectively connected to the ring and the fastener; The sliding adjustment module is fixed to the support rod through the annular member and the fixing screws; and the sand load input module is fixed to the sliding adjustment module through the fasteners.

4. The sand load measuring device according to claim 1, characterized in that: The base is provided with protruding structures on both sides, each of which is provided with a through hole, and the specimen fixing module is connected to the base via screws provided in the through holes; The specimen fixing module includes: two fixing rods respectively located on both sides of the angle steel specimen, screws in the two through holes and a tension knob located at the head of the screw; one end of the fixing rod away from the angle steel specimen is connected to the tail of the screw in the through hole located on the corresponding side; the tension knob is used to adjust the tightness of the fixing rod clamping the angle steel specimen.

5. The sand load measuring device according to claim 4, characterized in that: The fixing rod is an elastic member; The strain gauge is arranged on the central axis of each of the fixing rods and is used to measure the strain value of the fixing rod.

6. The sand load measuring device according to claim 2, characterized in that: The sand load input module is a funnel; The acceleration sensor adopts a capacitive MEMS acceleration sensor, and the acceleration sensor is attached to the angle steel specimen.

7. A sand load measurement method, characterized in that: Applicable to the sand load measuring device as claimed in any one of claims 1 to 6, the sand load measuring method comprising: Fixing the angle steel specimen on the specimen fixing module, and adjusting the magnitude of the restraining force applied to the angle steel specimen through the specimen fixing module, so that the angle steel specimen is under a preset restraining condition; Measuring a first resistance of the strain gauge, and calculating a first strain value according to the first resistance; Adjust the sliding adjustment module to the preset height; A preset amount of sand is placed in a sand load input module, and the sand load input module applies a sand load to the angle steel specimen; When the sand load is applied, the acceleration of the angle steel specimen is measured by an acceleration sensor, and the vibration frequency of the angle steel specimen is obtained according to the acceleration of the angle steel specimen; When applying the sand load, measuring the second resistance of the strain gauge, and calculating the second strain value according to the second resistance; The magnitude of the sand load on the angle steel specimen is calculated based on the first strain value and the second strain value.

8. The sand load measurement method according to claim 7, characterized in that: The sand load measurement method further comprises: By adjusting the specimen fixing module, the constraint condition of the angle steel specimen is changed to change the vibration frequency of the angle steel specimen; By measuring the strain value of the strain gauge under different constraint conditions, the sand load on the angle steel specimen at different vibration frequencies is obtained.

9. The sand load measurement method according to claim 7, characterized in that: The step of obtaining the vibration frequency of the angle steel specimen according to the acceleration of the angle steel specimen comprises: According to the acceleration of the angle steel specimen, a discrete Fourier transform method is used to obtain the acceleration spectrum; The frequency corresponding to the spectrum peak of the spectrum is obtained to obtain the vibration frequency of the angle steel specimen.

10. The sand load measurement method according to claim 7, characterized in that: The step of calculating the sand load on the angle steel specimen according to the first strain value and the second strain value includes: Calculating a strain difference value according to the first strain value and the second strain value; Based on the strain difference, the stress is calculated according to the Young's modulus expression; Based on the stress and according to the relationship between stress and force, the sand load on the angle steel specimen is calculated.

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