A comprehensive damage criterion in tube hydroforming

Abstract

In the present study, the Johnson-Cook damage model is proposed as a comprehensive damage criterion to predict all types of probable failures in tube hydroforming process. Also, the Johnson-Cook material model is used to predict the profile of hydroformed tubes and their dimensions. The validity of numerical results was verified using experimental results obtained in this study. Moreover, because of the importance of friction force in this process, existing between the tube and die, the friction coefficient is determined using the ring compression test, separately. The comparison of experimental and numerical results shows that Johnson-Cook damage model can predict all of the possible failures in tube hydroforming process correctly, both in terms of location and loading conditions. And this model does not predict any failure if, the tube is hydroformed perfectly. Additionally, it was cleared that the Johnson-Cook material model is a proper model to predict the profile of hydroformed tubes with remarkable accuracy. Also, it was found that the loading path and creation of a proper wrinkling have a determinative and vital role in the prosperity of the process.

A New Semi-Analytical Solution for an Arbitrary Hardening Law and Its Application to Tube Hydroforming

“…All these solutions have been found at . This value is typical for tube hydroforming processes [ 19 ].…”

“…Using the solution above, one needs to evaluate the integral in Equation (41) for calculating the dimensionless pressure. Figure 2 shows the effect of the loading path on the variation of the inner pressure with the inner radius for St37 steel, assuming that [ 19 ]. As expected, the pressure increases as decreases (i.e., increases).…”

“…Damage mechanics models are often used to predict fracture initiation in tube hydroforming processes [ 19 , 21 ]. A wide class of damage mechanics models is based on ductile fracture criteria [ 26 ].…”

“…Fracture often initiates at the outer surface [ 19 ]. It follows from Equation (5) that at the fracture initiation site.…”

Investigation of hydroforming process loading paths based on experimental and improvement based on Sobol sensitivity analysis

“…They also used the Johnson-Cook material model to predict the characteristics of hydroform pipes and their dimensions. They conclude that this model can accurately predict all possible failures in the hydroforming process in terms of position and in terms of pipe loading conditions, and a suitable model for predicting the characteristics of hydroform pipes can be accurately observed [7]. Cigarette et al Conducted a general study on the possibility of hydroforming sheet metal as well as hydroforming and extrusion tubing.…”