To reveal the nonlinear dynamic behavior of gear rattling vibration caused by backlash, a 2-DOF oscillator model with spring and damping elements was established. Based on theory discontinuous dynamical systems, phase plane motion divided into three parts: domain tooth surface meshing motion, free back motion. Introducing global mapping local dynamics method, process teeth from impact to then a...

We study the force vs extension behaviour of a helical spring made of a thin torsionally-stiff anisotropic elastic rod. Our focus is on springs of very low helical pitch. For certain parameters of the problem such a spring is found not to unwind when pulled but rather to form hockles that pop-out one by one and lead to a highly non-monotonic force-extension curve. Between abrupt loop pop-outs t...

In this paper an impulse-based method for cloth simulation is presented. The simulation of cloth is required in different application areas like computer animation, virtual reality or computer games. Simulation methods often assume that cloth is an elastic material. With this assumption the simulation can be performed very efficiently using spring forces. The problem is that many textiles canno...

The set of coordinates used to describe the motion of a dynamic system is not unique. For example, consider an elastic pendulum (a mass on the end of a spring). The position of the mass at any point in time may be expressed in Cartesian coordinates (x(t), y(t)) or in terms of the angle of the pendulum and the stretch of the spring (θ(t), u(t)). Of course, these two coordinate systems are relate...

Zero stiffness structures have the remarkable ability to undergo large elastic deformations without requiring external work. Several equivalent descriptions exist, namely i) continuous equilibrium, ii) constant potential energy, iii) neutral stability and iv) zero stiffness. Each perspective on zero stiffness provides different methods of analysis and design. This paper reviews the concept of z...

We present a one-dimensional, multiscale mass-spring model to describe the response of vertically aligned carbon nanotube (VACNT) foams subjected to uniaxial, high-rate compressive deformations. The model uses mesoscopic dissipative spring elements composed of a lower level chain of asymmetric, bilateral, bistable elastic springs to describe the experimentally observed deformation-dependent str...

The string pendulum consists of a mass attached to the end of an inextensible string which is fastened to a support. Applying an external forcing to the pendulum’s support is motivated by understanding the behavior of suspension bridges or of tethered structures during earthquakes. The forced string pendulum can go from taut to slack states and vice versa, and is capable of exhibiting interesti...

All of the low back braces available today are fabricated to provide anteriorly or posteriorly directed forces . None accomplishes satisfactory immobilization, and, in fact, braces with a high thoraco-lumbar purchase area increase lumbosacral motion (1) . Attempts to improve the lumbar immobilization by applying increased abdominal pressure are useful to a limited degree, as in the Williams bra...