Measuring method of axial tensile strength of concrete based on Hopkinson's principle

Abstract

The invention discloses a method for measuring the axial tensile strength of concrete based on Hopkinson's principle. The axial tensile strength of a concrete specimen (10) is measured using a Hopkinson compression bar device, which is characterized in that: removing the The transmission rod in the Hopkinson pressure rod device; the test piece (10) is provided with a group of strain gauges (50) at the distance from the impact end; the free end (11) of the concrete shaft test piece (10) An accelerometer (30) is set; the acceleration of the free end of the test piece (11) is obtained by analyzing the waveform diagram monitored by the accelerometer (30); the free end of the test piece ( 11) Surface velocity; measure the velocity of the free end (11) of the test piece, and then measure the axial tensile strength of the concrete test piece (10) through calculation and analysis. The invention can accurately measure and calculate the tensile strength of the concrete axis under the condition of medium and high strain rate.

Description

technical field [0001] The invention relates to a method for measuring the axial tensile strength of concrete, in particular to a method for measuring the axial tensile strength of concrete based on Hopkinson's principle. Background technique [0002] Concrete material is the most ubiquitous construction material and is widely used in various industries. Under the action of high-speed loads such as explosion and impact, it is necessary to accurately know the axial tensile strength of concrete to determine the accidental load that concrete can bear. At present, in terms of measuring the axial tensile strength of concrete, the method commonly used at home and abroad is mainly the hydraulic servo experimental system, but it is limited to the general low strain rate condition, and the concrete axial tensile strength under the higher strain rate condition The measurement of the tensile strength of the heart is still very difficult, mainly because the higher strain rate means tha...

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Problems solved by technology

This method is to directly paste the strain gauge on the concrete specimen, and the maximum value of the tensile strain recorded directly on the strain gauge, under the assumption of the material, the product of the maximum value of the tensile strain and the elastic modulus is used as the material However, as the distance from the fracture position increases, the reflected tensile stress decreases significantly, and the peak value of the emitted tensile stress wave measured far away from the fracture position cannot represent the tensile strength of the concrete material. Therefore, this measurement method The disadvantage is that it is only suitable for low strain rate conditions, but cannot be applied to the measurement of concrete axial tensile strength under medium and high strain rate conditions.

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