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Investigation of acoustic-plastic constitutive modeling based on Johnson-Cook model and numerical simulation application

Wang Xingxing, Qi Zhenchao, Chen Wenliang

Archives of Civil and Mechanical Engineering

2021

Vol. 21, no. 2

605--620

In this paper, a modified acoustic-plastic Johnson–Cook model for Ti–45Nb alloy was established, which can be used to reveal the metallic deformation behavior under ultrasonic vibration-assisted (TUV) forming. First, the experiments of traditional compression and TUV compression were carried out, the influence of vibration amplitude on yield strength, strain hardening coefficient and index, and strain rate hardening coefficient. The yield strength reduction is caused by the acoustic softening effect. The yield strength and strain hardening coefficient present a negative correlation with amplitude increase, the strain hardening index and strain rate hardening coefficient present a positive correlation with amplitude increase. Further, the accuracy of the developed constitutive model was quantitatively identified, the relative coefficient is as high as 0.954, the mean absolute percentage error less than 5.42%. On this basis, a user-defined subroutine was developed to implement the numerical simulation of the TUV forming processes using the finite element method, the results of numerical simulation and experiment are in good agreement, and prediction accuracy is as high as 95.25%. Therefore, the developed constitutive model can be well revealed the material deformation behavior and provides an application guide.

Simulating progressive damage of notched composite laminates with various lamination schemes

Mandal B., Chakrabarti A.

International Journal of Applied Mechanics and Engineering

2017

Vol. 22, no. 2

333--347

A three dimensional finite element based progressive damage model has been developed for the failure analysis of notched composite laminates. The material constitutive relations and the progressive damage algorithms are implemented into finite element code ABAQUS using user-defined subroutine UMAT. The existing failure criteria for the composite laminates are modified by including the failure criteria for fiber/matrix shear damage and delamination effects. The proposed numerical model is quite efficient and simple compared to other progressive damage models available in the literature. The efficiency of the present constitutive model and the computational scheme is verified by comparing the simulated results with the results available in the literature. A parametric study has been carried out to investigate the effect of change in lamination scheme on the failure behaviour of notched composite laminates.