Mechanical structure fatigue damage online monitoring test device

Abstract

The invention discloses a mechanical structure fatigue damage online monitoring test device including a cantilever beam specimen with one end fixed; the other end of the cantilever beam specimen is connected with a reciprocating driving mechanism for driving the cantilever beam specimen to swing. The test device also includes a strain transducer for measuring the strain quantity transmitted from the reciprocating driving mechanism to the cantilever beam specimen and a strain transducer for measuring the strain quantity of the cantilever beam specimen in a swinging process. According to the test device, the adopted reciprocating driving mechanism and the adopted cantilever beam specimen are in connection state, and a cantilever beam is suffered from force applied by the driving mechanism in the swinging process, so that the cantilever beam specimen is avoided from being suffered from superposed vibration of the reciprocating driving mechanism in the swinging process, and the driving way is closer to an actual situation; with utilization of the strain transducers, information characterizing a mechanical structure fatigue state can be obtained, and thus the equivalent elasticity modulus of a mechanical structure is obtained, and the fatigue condition of the mechanical structure can be obtained through assessment of a change law of the equivalent elasticity modulus.

Description

technical field [0001] The invention belongs to the technical field of mechanical structure strength testing, and in particular relates to an online monitoring test device for mechanical structure fatigue damage. Background technique [0002] Under the action of external alternating loads, the material properties of the mechanical structure show an irregular attenuation process, which is the whole process of the occurrence, development, formation of macroscopic cracks, spalling and fracture of the so-called fatigue cracks. Fatigue damage has become an important factor leading to the failure of mechanical structures. According to statistics, the fatigue fracture damage that occurs in engineering practice accounts for 50% to 90% of all mechanical damage, and fatigue damage fracture is the most common form of mechanical structure failure. Therefore, damage fractures caused by fatigue are becoming more and more prominent in engineering failures. How to monitor the fatigue info...

AI Technical Summary

Problems solved by technology

The disadvantage of this vibration system is that when the exciter exerts a periodic force on the elastic beam, the exciter and the cantilever beam are in a contact and non-connected state

According to the calculation, the amplitude required for the fatigue damage of the sample is greater than the installation gap between the exciter and the sample, which causes collision interference between the exciter and the sample, so the method of exciting vibration is not feasible; in addition, the actual Most of the mechanical equipment in the project is driven by motors, and the driving mode of the vibrator does not match the actual working conditions

Images