Comparison of Constitutive Models for Predicting the Formability of SS 304 by Tubular Hydroforming Process

1. Introduction

Tube hydroforming (THF) is a high-tech manufacturing method that creates precise shapes with precise dimensions. Though THF techniques are utilised in various industries such as automotive and aerospace, the development of the process requires expensive tools because the process is based on experimentation. THF is widely employed in various industries to accomplish weight reduction, fewer parts, and lower costs (Ge et al., 2017) due to significant advancements in PC controls and pressure drive frameworks. A brief summary on THF can be observed in literature (Alaswad et al., 2012). The higher formability of materials means to create successful forming behavior. There are many methods in the form of analytical and experimental models developed to generate FLC for different sheet metals. FLC was first introduced by Keeler (Keeler, 1961), later; many researchers have worked on the formability of sheet metal with the help of numerical and experimental methods (Hashemi et al., 2014; Safikhani et al., 2009; Zhang et al., 2018). But, the inference of FLCs by THF is a novel area in view of the difficulties connected with the process. The noteworthy process of disappointment in this action is predictable to wrinkling and bursting. The reasons for these types of failures were already explored in the literature works (Alaswad et al., 2012; Ge et al., 2017; Wang & Peng, 2016).

Based on the above statements, it is clearly understood that there are many pitfalls in the THF that are to be explored in order to improve the utilization of the process. To initiate these issues, many works have been carried out to predict strain records which aren’t continuous by the controlled experimental facts as explained by Asnafi and Skogsgardh (2000) in their work. Zhang et al. (2011) surveyed various necking criterions which are usually applicable to botht sheet and tube forming process. To investigate the necking criterions, Al 5086 was considered to study the formability based on numerical simulation. The obtained results are in good connection with the experimental results in terms of failure and loading predictions. Thanakijkasem et al. (2015) developed and compared various FE models with the experimental values of SS 304 for THF process. FLC of SS 304 was taken into consideration to explore the formability of the tube during THF. The developed models were compared and analyzed and the prediction capability were explained in the study. Naghibi et al. (2016) developed a novel technique for the prediction of FLC for SS 304 during THF process. The authors considered the influence of process parameters on the FLC prediction and strain generations. The work finally concluded that developed method has a significant influence of process parameters in the accurate prediction of FLC during THF process. Wang et al. (2015) investigated on the constitutive modeling of the tubular material based on two different theories; total strain energy theory and incremental theory. The work presented the comparison of data from both the theories with the existing simulation data. The work concluded that the data obtained from total strain energy theory is in good agreement with the existing simulation data.