A loading device for precise control of rivet pre-tightening force in riveted structure

Abstract

The invention designs a loading device for precisely controlling the pretightening force of rivets in riveted components. The device consists of a bolt 1, a ring clamp 2, a strain gauge 6 attached to the outside of the ring clamp, a pin 3 and a pressure block 7. The strain gauge is in a vertical direction, and the load applied when the bolt is tightened acts on the pin 3. . The test method is to tighten the bolt 1 to compress the pressure block 7, and connect the external static strain gauge through the strain gauge attached to the ring fixture 2 to measure the strain generated by the pre-tightening force applied by the bolt, according to the corresponding pre-tightening force formula , can accurately calculate the preload required for the test. The principle of the method is reliable, the loading force is uniform, the test accuracy is high, the recorded data and analysis results are accurate, and it avoids the unfavorable factors caused by the fretting fatigue test of riveting under the premise of not knowing how much pre-tightening force is applied. It is especially suitable for riveting research Effect of Structural Preload on Fatigue Life.

Description

technical field [0001] The invention relates to a test method, in particular to a loading device for precisely controlling the pretightening force of rivets in a riveted structure. Background technique [0002] Fretting fatigue widely exists in various mechanical components, especially the connection with rivets, bolts, pins and other interference methods. Due to the characteristics of reliable connection, light weight and low cost, riveting is widely used in the connection of structures. The fatigue performance of riveted components is affected by many factors such as riveting process, structural material, external load and so on. In the riveting process, the rivet pressure force has a great influence on the fretting fatigue damage of the riveted structure: large pressure riveting force will lead to large rivet pre-tightening force, and fretting fatigue cracks will initiate at the edge of the rivet head; small pressure riveting force will cause rivet pre-tightening force ...

AI Technical Summary

Problems solved by technology

However, none of the above methods can effectively measure the pre-tightening force of the riveting fretting fatigue test.

For example, using reasonably designed bolts to simulate the method of riveting fretting fatigue test, although this method can measure the pre-tightening force through the wrench torque, but with the continuous change of the test load and times, it is impossible to understand and master the riveting in time The pre-tightening force of the fretting fatigue test will have a great change in the test results, so that the accurate test data and results cannot be obtained; while the test method of directly riveting the rivet is in the process of riveting the rivet It will produce a large plastic deformation, so it is impossible to know the accurate preload of the test

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