Development of a photomicroscope method for in situ damage monitoring under ultrasonic fatigue test

Abstract

PurposeMechanical issues related to the information and growth of small cracks are considered to play a major role in very high cycle fatigue (VHCF) for metallic materials. Further efforts on better understanding in early stage of a crack are beneficial to estimating and preventing catastrophic damage for a long period service.Design/methodology/approachDependent on the ultrasonic loading system, a novel method of in situ photomicroscope is established to study the crack behaviors in VHCF regime.FindingsThis in situ photomicroscope method provides advantages in combination with fatigue damage monitoring at high magnification, a large number of cycles, and efficiency. Visional investigation with attached image proceeding code proves that the method has high resolution on both size and time, which permits reliable accuracy on small crack growth rate. It is observed that the crack propagation trends slower in the overall small crack stage down to the level of 10–11 m/cycle. Strain analysis relays on a real-time recording which is applied by using digital image correlation. Infrared camera recording indicates the method is also suitable for thermodynamic study while growth of damage.Originality/valueBenefiting from this method, it is more convenient and efficient to study the short crack propagation in VHCF regime.

Random fatigue life analysis of carbon fiber‐reinforced plastic for automotive drive shaft with environment temperature data

“…It is an important aspect of determining whether a product can meet usage requirements. [40][41][42] Miner's law is the most widely used cumulative damage criterion for fatigue life calculation. It has the advantage of being simple and easy to use.…”

“…Fatigue cumulative damage theory investigates the fatigue damage evolution law and failure criteria when the material is subjected to load. It is an important aspect of determining whether a product can meet usage requirements 40–42 . Miner's law is the most widely used cumulative damage criterion for fatigue life calculation.…”

Fatigue life prediction of eccentric springs for the automobiles considering residual stress

“…And some scholars have also put forward some new methods to solve the fatigue problem 15–17 . A microscopic observation method of in situ damage was proposed 18 . It had a high resolution in size and time and could reliably measure the propagation rate of small cracks.…”

“…[15][16][17] A microscopic observation method of in situ damage was proposed. 18 It had a high resolution in size and time and could reliably measure the propagation rate of small cracks. The original sample using an error circle was studied to improve the accuracy of the parameter prediction of small sample data.…”

The prediction of residual life of liquid-storage tank considering the tank wall surface state

“…And the functions of length diameter ratio of initial crack, crack depth and relative spacing are obtained (Ye et al, 2020). These studies are based on fatigue theory and linear elastic fracture mechanics (Viana et al, 2021;Liu et al, 2017;Deng et al, 2022;Tan et al, 2022).…”