A novel material modeling technique in the single-point incremental forming assisted by the ultrasonic vibration of low carbon steel/commercially pure titanium bimetal sheet

A new theoretical model was presented based on the conversion of ultrasonic vibration to heat. The provided model was used as the definition of material behavior in the finite element simulation. According to this model, the temperature of the tools increased rapidly in the early stages of vibration and then reached to a constant value. The experimental results showed the reduction of the amount of force and coefficient of friction under the influence of vibration. In this regard, good congruence was obtained between the results of the numerical solution and the experimental results. To further understanding the effect of ultrasonic vibrations on material properties, the microstructures of deformed specimens were examined. Microscopic observation of specimens under the influence of vibration showed equiaxed fine grains along the primary grain boundaries which their partial volume in the structure was increased by increasing the vertical step down and horizontal feed rate.