This paper studies the interaction between non-viscous damping and nonlinearities for nonlinear oscillators with reflection symmetry. The non-viscous damping function is an exponential damping model which adds a decaying memory property to the damping term of the oscillator. We consider the case of softening and hardening behaviour in the frequency response of the system. Numerical simulations ...

A type of nonlinearity in vibrational engineering systems emerges when the restoring force is a nonlinear function of displacement. The derivative of this function is known as stiffness. If the stiffness increases by increasing the value of displacement from the equilibrium position, then the system is known as hardening type oscillator and if the stiffness decreases by increasing the value of ...

We show how to achieve large-amplitude oscillation and good frequency stability in a nonlinear NEMS oscillator by using a softening nonlinearity to locally balance the hardening behaviour of the Duffing nonlinearity for a given motion amplitude. The case when the softening behaviour is obtained via electrostatic biasing is theoretically investigated, under parallel-plate assumptions, for a full...

Control-based continuation (CBC) is a means of applying numerical continuation directly to a physical experiment for bifurcation analysis without the use of a mathematical model. CBC enables the detection and tracking of bifurcations directly, without the need for a post-processing stage as is often the case for more traditional experimental approaches. In this paper, we use CBC to directly loc...

this paper presents a macro model to predict unreinforced masonry structures in plane behavior. the model is based on the concept of multilaminate theory. in the past, the method has been used to model behavior of soil, disregarding the cohesion and the tensile strength. regarding its mathematical base, and the possibility of applying in other cases, this method is used to predict the ultimate ...

In the present effort, a data-driven modeling approach is undertaken to forecast aperiodic responses of non-autonomous systems. As representative system, harmonically forced Duffing oscillator considered. Along with it, an experimental prototype studied. Data corresponding chaotic motions are obtained through simulations oscillators hardening and softening characteristics experiments bistable o...

The changes in the mechanical properties and microstructure of nanocrystalline Cu-Zn alloys deformed by cryorolling during low temperature annealing and the post-process deformation were studied. The deformed Cu-Zn alloys exhibited uncommon anneal hardening and deformation softening behaviors. The degree of anneal hardening and deformation softening increased with the addition of the solute ato...

Recent Bauschinger-type tests conducted on a twinning-induced plasticity (TWIP) steel highlights the important contribution of internal stresses to work hardening [1]. Along this line we present Bauschinger experiments in a Fe-22Mn wt.%-0.6C wt.% TWIP steel. The mechanical behaviour upon load reversal shows transient and permanent softening effects. Determination of the internal stress from the...

a constitutive model based on two–dimensional unstructured galerkin finite volume method (gfvm) is introduced and applied for analyzing nonlinear behavior of cracked concrete structures in equilibrium condition. the developed iterative solver treats concrete as an orthotropic nonlinear material and considers the softening and hardening behavior of concrete under compression and tension by using...