Novel ring-on-ring biaxial bending strength test clamp and positioning cover thereof

Abstract

The invention discloses a novel ring-on-ring biaxial bending strength test clamp and a positioning cover thereof. A containing cavity is formed in the bottom of the positioning cover, and the size ofthe containing cavity corresponds to a test sample; an installing mechanism is arranged at the bottom of the positioning cover; a channel is formed in the top of the positioning cover, and the size ofthe channel corresponds to the size of a loading ring installing part; the channel position is designed as follows: when the positioning cover is installed on a supporting ring installing part through the installing mechanism, the middle shaft of a loading ring is overlapped with the middle shaft of a supporting ring; the position of the containing cavity is designed as follows: when the positioning cover is installed on the supporting ring installing part through the installing mechanism, and the middle shaft of the containing cavity is overlapped with the middle shaft of the supporting ring. The clamp comprises the positioning cover, the supporting ring, the supporting ring installing part, the loading ring and the loading ring installing part. According to the positioning cover in theinvention, the middle shafts of the loading ring, the supporting ring and the test sample can be aligned rapidly and accurately, the test efficiency and the accuracy rate of the test result are improved; the clamp can be used for storing sample fragments and preventing the sample fragments from being sputtered.

Description

technical field [0001] The invention relates to a biaxial bending test tool assembly, in particular to a positioning cover in a ring-on-ring biaxial bending strength testing tool, and a novel ring-on-ring biaxial bending strength testing fixture comprising the positioning cover. Background technique [0002] Ring-on-ring biaxial bending test (ring-on-ring biaxial bending test) is a classic method to test the bending strength of structural ceramics. According to the ASTM standard, the fixture consists of a loading fixture consisting of a loading ring mounting part and a loading ring, and a supporting fixture consisting of a supporting ring mounting part and a supporting ring (such as figure 1 As shown), the test sample is positioned between the loading ring and the support ring, and the relative movement of the upper and lower rings in the vertical direction causes the sample to bend. The bending strength is the maximum stress when the sample bends and breaks between the uppe...

AI Technical Summary

Problems solved by technology

First of all, when installing the fixture and sample, it is required that the central axis positioning of the loading ring and the support ring be accurate to 0.5% of the diameter of the support ring, and the central axis positioning of the sample and the upper and lower rings should be accurate to 2% of the diameter of the support ring. If the center offset is too large, the stress distribution will be uneven, and the starting point of the fracture will always be located near the loading ring. In actual operation, due to the large error of manual calibration, it is impossible to accurately align the three, resulting in invalid fracture and time-consuming

And during the relative movement of the loading ring and the support ring, the sample is displaced, and the line or point contact stress and friction between the upper and lower rings and the sample will cause stress concentration, so that the stress of the sample is beyond the actual bending strength. lower fracture, resulting in inaccurate experimental results

In addition, due to the lack of a structure for accommodating the sample, the device is not easy to collect after the sample is broken, which is not convenient for later experiments

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