An experimental and numerical study of necking initiation in aluminium alloy tubes during hydroforming

Study on experimental approaches of forming limit curve for tube hydroforming

“…Davies et al [10] proposed a tooling and experimental apparatus to establish the FLC for AA6061 tube based on the free-expansion tube hydroforming with axial force and internal pressure. Kulkarni et al [11] conducted a combined experimental and numerical investigation of free hydroforming of aluminum alloy tubes, which are subjected to different loading histories involving axial compression and internal pressure. Hwang et al [12] carried out bulge tests with axial feeding and internal pressure to establish the FLC of tubular material AA6011.…”

A numerical study of the effect of loading conditions on tubular hydroforming

“…They found that the strain paths can be non-proportional, which contradicts the assumption made in analytical studies such as (Chow and Yang, 2002;Kim and Kim, 2002).However, continuous recording of strains was not undertaken in their experiments.Further, the role of strain histories on peak pressure and the mechanics of failure due to necking was not systematically assessed. These issues were examined in a very recent work by Kulkarni et al (2004). They performed free hydroforming experiments using aluminium alloy tubes which were mounted between specially designed end grips on the platform of an INSTRON testing machine.…”

“…The observations made in Asnafi and Skogsgardh (2000); Kulkarni et al (2004), while emphasizing the role of strain paths, are limited to prescribed fluid pressure along with stroke. In other words, the effects of various types of loading conditions such as specified fluid volume flow rate in conjunction with axial end displacement or force on formability of tubes have not been examined.…”

“…In this paper, axisymmetric finite element simulations of free hydroforming of aluminium alloy tubes employed in the experiments of Kulkarni et al (2004) are carried out corresponding to various types of loading conditions. These involve prescribed fluid pressure or volume flow rate in conjunction with axial end displacement (contraction or extension).…”

Finite element modeling of tube hydroforming of polycrystalline aluminum alloy extrusions

“…due to local instability during tube hydroforming. Prediction of failure initiation using finite element method and applying stability criteria was investigated by Aydemir et al (2005), Kulkarni et al (2004), , and .…”