Computational Study of Ultrasonically-Assisted Turning of Ti Alloys

Abstract

Abstract:The industrial applications of titanium alloys especially in aerospace, marine and offshore industries has grown significantly over the years primarily due to their high strength, light weight as well as good fatigue and corrosion-resistance properties. The machinability of these difficult-to-cut metallic materials using conventional turnning (CT) techniques has seen a limited improvement over the years. Ultrasonically-assisted turnning (UAT) is an advanced machining process, which has shown to have specific advantages especially in the machining of high-strength alloys. In this study a three-dimensional finite element model of ultrasonically-assisted oblique cutting of a Ti-based super alloy (Ti15V3Cr3Al3Sn) is developed. The nonlinear temperature-sensitive material behaviour is incorporated in our numerical simulations based on results obtained with split-Hopkinson pressure bar tests. Various contact conditions are considered at the tool tip-workpiece interface to get an indepth understanding of the mechanism influencing the cutting parameters. The simulation results obtained are compared for both CT and UAT conditions to elucidate main deformation mechanisms responsible for the observed changes in the material's responses to cutting techniques.

Dynamic Behaviour of β-Ti-15333 in Ultrasonically Assisted Turning: Experimental and Numerical Analysis

“…An engineering assumption was used to extrapolate the materials' response at 10 10 s 1 , which is 20% higher than the measured level of stress-strain response at 3300 s 1 . The interpolated material response of the studied material at 3300 s 1 is presented in Figure 14 [6,21,22]. The level of stresses obtained from the FE model was lower than the actual materials' response obtained from SHPB test.…”

Enhanced ultrasonically assisted turning of a β-titanium alloy

“…A higher a p inevitably leads to higher cutting forces and temperatures in the process zone during machining as demonstrated in the numerical studies [19,28]. Also, numerical models of UAT predict somewhat higher temperatures of the process zone when compared to CT for the same machining conditions [29].…”

Experimental investigations on effects of frequency in ultrasonically-assisted end-milling of AISI 316L: A feasibility study

“…In this work, the cutting speed variation (23.5-39.3 m/min) was not statistically large enough to induce a response above the noise level in both surface roughness and residual stresses. The small variation of the cutting speed in respect to the high-frequency low-amplitude vibration had no statistically measurable effects ,thus indicating a lack of complete separation between the tool and the work-piece [5,20]. Previous studies did observe a rather small effects of cutting speed on roughness especially in the case of small vibration amplitude (~2 m) at slow cutting speed [23].…”

“…Surface quality was observed to improve when comparing vibration aided turned or milled specimens with conventionally manufactured ones [17,18] as a result of improved behavior of material under high-strain regime [19,20,21,22].…”