In the event of earthquake-induced liquefaction, structures with shallow foundations can suffer excessive settlement and rotation. this paper, rotational response resting on liquefiable layers thickness equal to or smaller than width foundation is examined through a series dynamic centrifuge experiments. Moment–rotation backbone curves are extracted corresponding evolution rocking stiffness inc...

Rao, Nikhil V. M.S.M.E, Purdue University, December 2013. Analysis of an Actuated Two Segment Leg Model of Locomotion. Major Professor: Dr. Justin E. Seipel, School of Mechanical Engineering. Research studies on dynamic models of legged locomotion have generally focused on telescoping-type leg models. Such telescoping spring loaded inverted pendulum (SLIP) models have been able to accurately pr...

ATRIAS is a human-scale 3D-capable bipedal robot designed to mechanically embody the spring-mass model for dynamic walking and running. To help bring the extensive work on this theoretical model further into practice, we present the design and validation of a spring-mass robot that can operate in real-world settings (i.e. off-tether and without planarizing restraints). We outline the mechanisms...

This paper discusses two approaches to modeling helical suspension springs for use in a dynamic finite element compressor model. The first approach represents the spring's stiffness characteristics with a simple spring element matrix. The appropriate spring constants are calculated using a separate finite element model of the spring. The spring modeling procedure is described and supplemented w...

A family of mem-models, including the mem-dashpots, mem-springs, and most recently, mem-inerters, is emerging as a new powerful way capturing complex nonlinear behaviors materials systems under various types dynamic loads involving different frequency, amplitude, loading histories (e.g., hysteresis). Under framework state-space representation hybrid dynamical systems, mem-springs may be formula...

With the assumption of a linear-dashpot interaction force, we compute the coefficient of restitution as a function of the elastic and dissipative material constants, k and γ by integrating Newton’s equation of motion for an isolated pair of colliding particles. It turns out that an expression ε(k,γ) widely used in the literature is even qualitatively incorrect due to an incorrect definition of ...

Landing mats that can undergo a large amount of area deformation are now essential for the safe completion of landings in gymnastics. The objective of this study was to develop an analytical model of a landing mat that reproduces the key characteristics of the mat-ground force during impact with minimal simulation run time. A force plate and two high-speed video cameras were used to record the ...