Physically-based modelling for sheet metal cone parts forming under blast loading

Roozbeh Alipour

doi:10.1051/meca/2021002

Abstract

Forming sheet metals under blast loading or the explosive forming technique has many advantages for productions, but it is restricted due to its accuracy. This paper introduces a novel theoretical-empirical study for explosive sheet metal forming based on the simple plasticity principles. It provides a method of producing the sheet metal cone parts forming under blast loading, including an analytical model and experimental validation. Firstly, a theoretical-empirical model for cone forming based on underwater explosion employing the impulse method is developed. The model on the whole revealed the relationships among the geometrical parameters of forming a process that is very useful to predict the certain explosive mass for complete forming a cone part. Afterward, a series of experiments are conducted to validate the developed model and also for the required modification in the solution. Comparing the theoretical-empirical solution and experimental results, the ability of the presented model for estimation of the explosive mass is demonstrated. Experimental results show that the theoretical model matched the experiments well.

Highlights

Cone forming is one of the sophisticated and difficult areas in sheet metal forming processes [1]
The effects of strain rate and deformation efficiency on the forming process are far more than those of the initial estimation employed in the analytical model
In the case of both points of view, Robustness ratio (Rr) may able to play a role in achieving a better estimation of explosive mass required for the complete forming process

Summary

Introduction

Cone forming is one of the sophisticated and difficult areas in sheet metal forming processes [1]. In the conventional deep drawing method, failure is too likely to come to pass on the specimen because of the low-contact area of the sheet with the punch in the first steps of forming. Since most of the sheet surface in the area between the punch tips and the blank holder is given free rein to form, wrinkles may occur on the flange or product wall [2,3]. Increased the mentioned development has led to several researches on the explosive forming of sheet metals from analytical, numerical and experimental points of view [32]. An experimental and numerical analysis of explosive free forming was carried out by Akbari Mousavi et al [34] to eliminate most of the trial-and-error work, and provide relatively close approximation of process parameters. The elongation of aluminum alloy sheet metal in the free explosive forming

Methods

Results

Conclusion