It is a reference for load cell research, manufacture and use enterprises.
The application of load cell technology in the field of civil engineering The state of civil engineering is complex, and the measurement of soil pressure and soil load is a basic link in the research of civil engineering experiments and an important content in engineering testing. Except that the earth pressure can be converted by measuring the deformation of the soil support structure under certain conditions, the earth pressure sensor is generally used for direct measurement. Through long-term observation of earth pressure, understand and evaluate the working state of the structure; verify the stress distribution theory, check the reliability of assumptions and calculation formulas, so as to provide design basis. The development and use of soil pressure and soil load sensors has been in the country for decades, and the scope of application has been expanding, mainly including: highway subgrade, retaining wall detection and monitoring; subway engineering underground structure testing; tunnel formation pressure detection, collapse monitor. On the vault of the tunnel arch wall, a plurality of long anchor bolts equipped with load cells are fastened to the stratum to detect the pressure change of the soil stratum. The principle of the earth pressure and soil load sensor is the same as that of the strain gauge load cell, and the manufacturing process is similar. The main application scope is: the monitoring of large dams, the layered embedding temperature and concrete shrinkage stress sensors; the monitoring of landslides, and the embedding of multiple Earth pressure, angular displacement and liquid level sensors; large buildings, high-rise building foundation monitoring, buried earth pressure and displacement sensors at a certain distance along a straight line. The structure of the soil pressure and soil load sensor is very similar to the disc type, disc type, and box type load cell, but due to the complex soil conditions and many influencing factors, it is difficult to develop. To design soil pressure and soil load sensors, civil engineering technology must be combined with load cell technology. When designing and manufacturing the structure, it should be done as far as possible: (1) The soil pressure sensor should be as close as possible to the deformation characteristics of the soil medium; (2) The structural shape and size of the elastic element should be scientific and reasonable; (3) The deformation of the pressure-bearing surface of the sensor should be as small as possible. (4) Find the best embedding method through experiments. The theoretical basis for designing strain-type earth pressure and soil load sensors is mainly the design theory of earth pressure sensors established by the Russian scholar Baranov. The following assumptions are adopted: (1) The soil medium is a linear deformable body and cannot bear tensile stress; ( 2) The sensor is cylindrical, and the working surface is assumed to move parallel to the plane under pressure; (3) The deformation of the sensor is extremely small compared to its size; (4) Since the sensor is usually harder than the soil, the deformation of the elastic element is caused by its free Produced by compression; (5) Discuss an infinite soil body, on which a uniformly distributed pressure acts, and the working surface of the sensor is parallel to the pressure acting surface. 3. Load cell technology is used for wind pressure and wind load monitoring of large steel trusses in steel structures With the continuous increase of transmission voltage in my country's electric power sector, transmission towers are becoming larger and larger, which proposes how to design and build transmission towers Guarantee the safety problem when the strong wind acts. Especially in coastal areas, there have been many accidents of damage to transmission towers under the action of typhoons. Therefore, it is necessary to measure the wind pressure, wind speed, deformation and wind pressure-strain curve when the transmission tower is subjected to wind load, so as to provide a basis for the design and construction of the transmission tower. The tower crane used in the construction of high-rise buildings also belongs to the steel truss structure. In order to ensure the construction safety, the length of the lifting arm and the safety load and wind load
Any resulting deformation should be monitored from time to time.
The traditional measurement method is to monitor with an anemometer, because
The mechanical inertia of the anemometer cannot respond in time, and the wind
There is no simple linear relationship between pressure and wind speed, and the measurement error is relatively large.
Hidden dangers of accidents.
In the world, micro-pressure sensors are used to measure iron towers and steel trusses
Actual wind pressure on top; pasted above towers and steel trusses
Resistive strain gauges, which measure the strain of each component to monitor stress changes
situation; or spot weld thin-plate load-transmitters on iron towers and steel trusses
Sensors to monitor wind load effects.
Although the structure of the wind pressure sensor is different from that of the load cell,
But the principle is the same as the manufacturing process. Wind pressure acts directly on the
On the diaphragm of the sensor, the diaphragm produces a micro-position proportional to the wind pressure
Move, so that the resistance of the resistance strain gauge pasted on the diaphragm changes
, measure this output change using a Wheatstone bridge circuit, and
Convert this output to a standard signal corresponding to this wind pressure, which is
Strain gauge load cell technology is fully achievable.
4. Application examples of load cell technology in other projects
(1) Measuring the tethering force of ship anchors and coastal platforms, multi-purpose
Welded and sealed high-range cylindrical load cell.
(2) The tension detection and monitoring of cable-stayed steel cables of long-span bridges should
Cylindrical pull-type load cells sealed by welding require 6
Month long-term stability test.
(3) Pile driving impact force measurement of foundation piling machine for high-rise buildings
For volume, low-profile washer-type load cells are used.
(4) Material control and weighing of concrete mixer and batching system
Welded sealed disc load cell for heavy measurement.
(5) The static and dynamic force measurement of the material testing machine adopts tensile force
The dual-purpose load cell for extension and compression requires good long-term stability.
(6) Oil drilling turntable torque measurement, hook load drilling pressure direction
Force measurement, tong torque measurement, downhole tool cable tension measurement
etc., applying various load cells.
(7) It is used for overload measurement, monitoring and alarming of elevators in high-rise buildings
Load cells, mainly pressure load cells with shock pads,
Scissors fixed at both ends installed on a steel wire rope or steel belt to measure tension
Beam-cut load cells, etc.
