Experimentally valided approach for the simulation of the forging process using mechanical vibration

Control of a multi-degree of freedom worktool for vibrations assisted forging

“…Some studies have demonstrated that applying ultrasonic vibrations superimposed to the movement of die can reduce the force, similarly to the previous solutions [3], [4]. More recently, it was shown that low frequencies vibrations with special or combined waveforms can achieve the same reduction of the forging force, with less power required [5]. This work addresses the control of a special active tooling that generates vibrations in different directions by combining several piezoelectric actuators.…”

Modeling and characterization of piezoelectric cantilever bending sensor for energy harvesting

“…It can be obtained by considering all the acceleration terms equal to zero and using the kinematic boundary conditions (3)(4)(5)(6)(7)(8)(9)(10)(11)(12), (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) and the equilibrium boundary conditions (4-2), (4-3), (4-4). The second term results from the application of the modal superposition to the rest of the response by using the simplified homogeneous equations of the equilibrium boundary conditions, in which V n (x) is the eigenshapes characterizing the deformation shape of piezoelectric cantilever and Á n (t) characterizes the amplitude of transverse displacement which is calculated by using the orthogonality properties.…”

“…(4-8) into Eq. (4-1), the eigenshapes V n (x) can be simplified by using the boundary conditions (3)(4)(5)(6)(7)(8)(9)(10)(11)(12), (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13), and (4-4) as: v n (x) = A n (c 2 (x) + 1 s 2 (x)) (4-9) To calculate the parameter A n , we wish the orthogonal basis formed by the eigenshapes V n (x) and V m (x) is orthonormal, by which the orthogonality properties can be obtained: For m = n, Eq. (4-11) allows to calculate the parameter A n .…”

“…This model allows providing the transfer functions between the inputs (for example, an external force F(s)) and the outputs (for example, a transverse displacement and a voltage V(s)) which can present the dynamic behaviour in difference kinds of the mode shapes by time and frequency response. The model was implemented using Matlab software and will be able to integrate with the circuit model of energy storage [12], for instance, developed by Shen et al [7] and Ajitsaria et al [13]. The results obtained by analytical solution are compared with the experimental ones.…”

Design and causal modelling of a piezoelectric multi-actuator system used in forging processes

“…By using ultrasonic vibrations, a significant reduction of force has been obtained during forging a specimen of plasticine [1], or one of aluminium [2]. The vibrations in low frequencies (from few Hertz to few hundreds Hertz), generated by piezoelectric actuators in the direction of forging motion, has been also proved to have an important influence in the reduction of forging force in the test with plasticine [3] or with a small metallic specimen [4], [5]. However, the maximal force generated by piezoelectric actuator in these studies is still limited.…”