Measurement of the descending section of brittle specimens and brittle fracture impact relief method

Abstract

The invention discloses a method for remission of the instantaneous brittle fracture impact during measurement of a descending branch of a brittle test piece. The method comprises the following steps: immediately reversely loading the test piece when detecting that the test piece enters an instantaneous brittle fracture critical state of the descending branch to ensure that a loading cavity originally connected with a high-pressure oil inlet pipe is switched into a low-pressure oil returning pipe so as to enable the pressure rapidly to decline; meanwhile, changing an original oil returning cavity into the loading cavity so as to enable oil in the loading cavity to drag a piston and prevent the piston from inertially sliding on the one hand, and quicken the pressure relief of the original loading cavity on the other hand; meanwhile, counteracting the releasing of elastic energy stored by the loading equipment and recovering of elastic deformation of the loading equipment by reverse recovering of a piston rod until the pressure of the original loading cavity is less than the bearing capacity of the test piece, thus realizing balance and recovering the normal control; and repeating until a test stop condition test piece is met. According to the method, a mechanical structure and control system hardware do not require to be added, and thus the cost is saved; an additional damping force is overlapped on the bearing capacity of the test piece, and measurement precision and data processing difficulty are not affected. Real-time proper response can be made for any tonnage of brittle fracture.

Description

technical field [0001] The invention relates to a method for measuring the descending section of a brittle test piece and brittle fracture impact mitigation, and belongs to the technical field of large-scale civil engineering structure tests. Background technique [0002] In the field of large-scale civil engineering structural test technology, the measurement of the descending section of brittle specimens such as plain concrete columns is a difficult problem in the academic circle, and the impact damage caused by the instantaneous energy release during slowing down of brittle failure is also a difficult problem in the academic circle. [0003] The control system and control algorithm currently used cannot predict the state of the test piece. When the brittle test piece enters the descending section, due to the extremely fast damage of the test piece, the system has not responded to the bearing capacity that has dropped at the previous moment. bearing capacity has become low...

AI Technical Summary

Problems solved by technology

[0004] One of the commonly used solutions is to increase the flow rate and shorten the system delay, but this requires more powerful motors and oil pumps, thicker oil pipes, more sophisticated components and higher costs

[0005] Another method is to connect the damping device in parallel with the test piece, which firstly increases the installation, measurement work and cost; secondly, due to the different tonnage of the brittle break point of different test pieces, the damping device can only play a protective role within the range of its own bearing capacity ;Due to a certain degree of nonlinearity in the damper, the difficulty of data processing is increased, and the accuracy of measurement results is also reduced

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