The application of the displacement sensor of Bestning company in the field of prestressing:
Shenzhen Bestning Technology Co., Ltd. specializes in the R&D, production and sales of linear displacement sensors, pull-rope linear displacement sensors, grating electronic rulers and digital display meters, LVDT displacement sensors, and internal and external current modules. Widely used in injection molding machinery, die casting machine, blow molding machine, prestressing, hydraulic equipment, railway guide rail monitoring, spraying equipment, medical machinery, petrochemical exploration, measurement systems and other fields, in terms of reliability, stability, accuracy and environmental adaptability , to win the unanimous approval of our customers.
The following is an introduction to the applications in the field of prestressing:
Prestressing concept Prestressing is short for prestressing. Before the structure is subjected to external load, stress is applied to the area under the external load in advance to improve the performance of the structure. Pre-compression stress can be used to resist the tensile stress or bending moment of the structure, and pre-tension stress can be used to resist the compressive stress of the structure. If you are good at using prestressing principles and techniques, it is possible to obtain the effect of improving the structural performance and the bearing capacity of the structure. The concept of prestressed tension: Prestressed tension is to add tension in the component in advance, so that the prestressed tension member is subjected to tensile stress, and then it produces a certain deformation to cope with the load on the steel structure itself.
Schematic diagram of test principle (omitted)
The effect of prestress tension: Before the engineering structural members are subjected to external loads, prestress is applied to the steel strands in the tension module to improve the bending resistance and stiffness of the members, delay the appearance of cracks, and increase the durability of the members. . For the mechanical structure, it means to generate stress in advance. Due to the large tension control error and measurement error in the traditional prestressed tension construction operation, the retraction value is unmeasurable, the synchronization rate of both ends is low, the dual control of the tension force and the tension force cannot be realized, and there is a lack of reliable process control methods and effective methods. Detection and evaluation methods and other shortcomings, so it was gradually replaced by intelligent and numerically controlled tensioning technology. Modern prestressed program-controlled (intelligent, numerically controlled) tensioning technology refers to the automatic control of tensioning operations based on automatic measurement and control technology based on computer intelligence and sensor technology. A modern program-controlled tensioning system consists of a program-controlled main engine and an operation front end. The front end of the operation includes measurement and control circuits, oil pumps, jacks, sensors and other components.
The working principle of the prestressed tensioning program control system: The system host consists of an industrial tablet computer and a special software system. The host wirelessly controls one or more measurement and control front-ends to work according to the preset tension parameters. The front end controls the oil pump motor through variable frequency output stepless speed regulation according to the host command, and at the same time monitors the working pressure of the jack and the elongation value of the steel strand and feeds it back to the host. According to the feedback data, the host computer calculates the next command to continue to remote control the front end, thus forming a closed-loop control. The prestressed tensioning program control system takes the tensioning force as the main control index and the elongation as the auxiliary control index, which truly realizes the dual control of the tensioning force and the elongation value, and ensures that the tensioning force and the elongation at both ends of the tensioning process are highly synchronized. . The synchronization difference is strictly controlled within the scope stipulated in the 2011 edition of "Technical Specifications for Construction of Highway Bridges and Culverts". During the test of the pre-tensioning force, the instrument can precisely control the tensioning pressure by controlling the oil return amount, so that the pressure and the tensioning rate during the tensioning process can be controlled. The retraction value of the clip and the elastic deformation of some steel strands in the jack cavity are measured by accurately stretching to the initial stress, so as to obtain the effective elongation value of the stretched steel strand. The tension program control system does not modify the jack. The measurement system is realized by an external ultrasonic measurement sensor, which can directly measure the length change value of the steel strand. Real-time reflection of the steel strand value under different tension forces, you can directly measure and read the retraction value.