Displacement measuring apparatus for concrete temperature-pressure tester and application thereof

Abstract

The invention relates to a shift measuring device of the concrete temperature-stress tester, which comprises two suits of same measuring sub system distributed on the two sides of the central axis of the concrete test unit (1), each sub system is formed by a laser shift sensor (5) and a carbon fiber rod (3) parallels to the central axis; one end of the carbon fiber rod is fixed on the main rim of the tester by fixed seat (2) and the other end fixes a laser shift sensor; the rod is supported by a plurality of guiding seats (4) of the main rim; the laser (7) sent by the laser shift sensor is parallel to the test central axis; the laser returns to when it sends to the measuring point (8) of the active end; the digital quantity is transmitted to the upper machine or the display unit to process by the digital interface (6).

Description

technical field [0001] The invention relates to the measurement field, in particular to a displacement measuring device of a concrete temperature-stress testing machine and its application. The device is a non-contact laser displacement measuring device. Background technique [0002] Constrained adjustable uniaxial temperature-stress testing machine is a kind of equipment for studying the early hydration characteristics, stress development, deformation modulus and creep of concrete. When a certain tensile pressure is applied to the concrete specimen or the temperature of the specimen is changed, the concrete specimen will produce a certain amount of deformation. [0003] At present, only a few companies and universities at home and abroad are engaged in the development of this product. Abroad, Japan's University of Tokyo and Switzerland and other related scientific research institutions are developing the test machine. In China, only the Institute of Building Materials, De...

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Problems solved by technology

[0005] In terms of the error caused by the deformation of the contact point, since the deformation of the concrete specimen is between 0.05 and 10 μm, and the deformation of the contact point is between 0.01 and 1 μm, the error caused by the deformation of the contact point is between 0.1% and 10%. That is, in the worst case, the error caused by the deformation of the contact point is 10%, and the measured data is seriously distorted

On the other hand, there is an overlapping interval between the deformation of the concrete specimen and the deformation of the contact point, so once the deformation of the concrete specimen is between 0.01 and 1 μm, in the worst case, the measured data reflect completely The deformation of the contact point is not the deformation of the concrete specimen. Therefore, the lower limit of the measurement range of this contact measurement method is 1 μm, that is, the measurement range of the contact measurement method is between 1 and 10 μm, so the deformation of the contact point will be limited. The measurement range of the entire measurement system limits the function of the testing machine, making it impossible for the testing machine to effectively study high-strength concrete

[0006] In terms of the error caused by the deformation of the machine base, since the displacement sensor is directly fixed on the machine base, the machine base will usually be deformed by temperature and tensile pressure, and this deformation is between 0.005 and 0.1 μm. , the resulting error is 0.05% to 1%. When the measurement accuracy of the displacement sensor is 0.5%, the measurement accuracy of the entire measurement system will still be greater than 1.5%.

[0007] In addition, because the concrete specimen will sway on the horizontal plane after being stressed, the current contact measurement device has not considered the impact of this sway on the measurement accuracy.

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