Nondestructive characterization of elastic modulus under different tensile stresses through laser ultrasound combined inversion technique

Nguyen Le Van, N. Jeyaprakash*, Che Hua Yang

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review


Stainless steel (SS) is widely used in many fields including aeronautics, automobiles, marine and mechanical industries due to its outstanding feature such as good corrosion resistance and hardness. However, changes in material properties under stress, particularly changes in Young's modulus, result in the formation of cracks, a reduction in load-bearing capacity, and fatigue damage. So, the structural integrity needs to be evaluated based on a precise measurement of mechanical properties. In this study, Stainless Steel 304 (SS-304) is used as the base material and various tensile stresses are applied ranging from 0MPa to 100MPa with increment of 10MPa in each step. Nondestructive Laser Ultrasound Technique (LUT) has been used to characterize the elastic modulus under various tensile stresses. An inverse program was developed based on the Particle Swarm Optimization (PSO) algorithms to determine material properties. Nonlinear Gauss fitting method was proposed and established the fitting equation and nonlinear curve for Young's modulus and residual stress. The outcome of this research shows that when tensile stress is applied, the mechanical properties decrease by shifting the dispersion curve and also it is evident that the dispersion curves move toward the high-frequency-thickness while increasing the tensile stress. When the tensile stress was increased from 0MPa to 100MPa, the value of Young's modulus decreased from 201.7GPa to 193.5GPa. Especially, the predominant changes were observed during 30-100MPa. This observation displays the bonding strength and binding energy between the atomics. Further, the proposed nonlinear Gauss fitting substantiated the experimental values and confirmed that the thickness accuracy is close to the inversion values, with an average difference of 4.32%. This research suggests a potential nondestructive method to determine the residual stress of a material by calculating the changes in the elastic modulus.

Original languageEnglish
Article number2450059
JournalInternational Journal of Modern Physics B
Issue number4
StatePublished - 10 02 2024
Externally publishedYes

Bibliographical note

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  • PSO algorithm
  • Poisson ratio
  • Stainless steel
  • Young's modulus
  • laser ultrasound technique
  • tensile stress


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