A consistent mixed finite element method for solving two-dimensional contact problems is presented. Derivations of stiffness equations for contact elements are made from a perturbed Lagrangian variational principle. For a contact element, both the displacement and pressure fields are independently assumed. In order to achieve a consisent formulation, thus avoiding any numerical instability, the...

In this paper, we deal with the stability analysis of an object grasped by fingers with linear stiffness in the case where the gravity effect is considered. The stability of the grasp is defined based on the potential energy of the grasp. The analysis problem is formulated as finding a condition of the stiffness parameters and contact points for the position of the center of gravity (COG) to ex...

Modeling of contact interfaces that inherently include roughness such as joints, clamping devices, and robotic contacts, is very important in many engineering applications. Accurate modeling of such devices requires knowledge of contact parameters such as contact stiffness and contact damping, which are not readily available. In this paper, an experimental method based on contact resonance is d...

We investigate the contact stiffness of an elastic half-space and a rigid indenter with randomly rough surface having a power spectrum C2D(q)proportional q(-2H-2), where q is the wave vector. The range of H[symbol: see text] is studied covering a wide range of roughness types from white noise to smooth single asperities. At low forces, the contact stiffness is in all cases a power law function ...

Contact resonance atomic force microscopy (CR-AFM) methods currently utilize the eigenvalues, or resonant frequencies, of an AFM cantilever in contact with a surface to quantify local mechanical properties. However, the cantilever eigenmodes, or vibrational shapes, also depend strongly on tip-sample contact stiffness. In this paper, we evaluate the potential of eigenmode measurements for improv...

During the analysis of reinforced concrete structures, the infill wall is usually simplified as a diagonal inclined strut to facilitate finite element modeling calculations. However, the actual seismic damage and single frame-filled wall pushover experimental results show that when the earthquake shear force is huge, the top of the infill wall and the beam–column connections are usually, thus t...

self-centering pier (scp) has been viewed as a remarkable accomplishment which is able to sustain major lateral loading with reduced structure damage in seismic engineering. stiffness deterioration observed in experiment is vital for the seismic performance of self-centering concrete pier. in this contribution, the associated stiffness deterioration with respect to the structural damage is mode...