The method of testing the impact force of the drop hammer structure based on the principle of stress concentration

Abstract

The invention belongs to the technical field of impact tests, and in particular relates to drop hammer structural design based on a stress concentration principle and a method adopting a Wheatstone full bridge circuit for testing impact force. Due to the fact that the elastic strain of a drop hammer is relatively small, in order to improve the test sensitivity, and improve the capacity of resisting disturbance, the drop hammer is made into a thin plate structure, holes are drilled in the middle of the plate, and the strain around the hole is improved through the stress concentration principle. The Wheatstone full bridge mode connecting circuit is adopted, so as to obtain the whole average strain of the drop hammer, to improve a temperature error and a non-linear error. Static load is adopted for calibrating the drop hammer, and a result shows that the output voltage has a linear relation with load. The method is different from a common drop hammer structure and test method, the drop hammer adopts the thin plate structure with two circular holes, each hole is internally and uniformly provided with 4 resistance strain gages, the eight resistance strain gages are connected to be the Wheatstone full bridge circuit, the output voltage is measured, and tested impact force is obtained according to calibration.

Description

Technical field [0001] The invention belongs to the technical field of impact testing, and specifically is a method for testing impact force by adopting a drop hammer structure based on the stress concentration principle. Background technique [0002] The test of dynamic mechanical properties of materials often uses a falling weight to load. In order to improve the measurement accuracy of the instantaneous impact force of the falling weight and reduce the test cost, the structure of the falling weight and its test method need to be designed according to the structure and loading method of the test piece. At present, the drop hammer testing machine in the laboratory uses piezoelectric sensors to test the impact force, which is relatively expensive and has poor anti-interference. For some large-scale structural impact experiments that need to be carried out in the field, it is necessary to make a self-made economical and practical drop hammer. The present invention is proposed to ...

AI Technical Summary

Problems solved by technology

At present, the drop weight testing machine in the laboratory uses a piezoelectric sensor to test the impact force, which is relatively expensive and has poor anti-interference performance.

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