Applying ultrasonic vibration in sheet metal forming can change its mechanism and improve formability. The uniaxial tensile bulging limit experimental setups were designed to study the relationship induced by excitation, results under different conditions analyzed. It was found that has effects on left right sides of diagram (FLD). Under same frequency, maximum increment major strain is about 9...

In Incremental Sheet Forming (ISF) strains can be obtained well above the Forming Limit Curve (FLC) that is applicable to common sheet forming operations like deep drawing and stretching. This paper presents an overview of mechanisms that have been suggested to explain the enhanced formability. The difference between fracture limit and necking limit in sheet metal forming is discussed. The neck...

It is argued that in the antiproton-proton annihilation into two mesons p̄p −→ m1m2, the origin of different angular momentum selection rules commonly obtained for planar annihilation diagrams A2 and for non-planar rearrangement diagrams R2 lies in the omission of momentum transfer between an annihilated antiquark-quark pair and a remaining quark or antiquark. Therefore, there is no reason for d...

This paper presents a comparison between a number of different failure prediction methods for superplastic forming processes. Attention is limited here to superplastic forming of Ti-6Al-4V at 927C. The failure prediction methods considered include the flow localisation factor approach, forming limit curves based on void growth models, such as the Rice and Tracey model and the Cocks and Ashby mo...

This study analyses the effect of martensite grain size and its volume fraction in dual-phase (DP) steel on (1) formability limit, (2) average global behavior under different loading conditions, (3) damage initiation. The virtual RVEs (Representative Volume Elements) were constructed using DREAM.3D software with a variation microstructural attributes. numerical simulations carried out DAMASK, w...