Interface slip

Interface slip factor a (m ). This factor is defined as a phenomenological parameter characterizing the lubrication behavior on the phase interface as a slide occurs. 

As demonstrated, Eq. (7) gives complete information on how the weight fraction influences the blend viscosity by taking into account the critical stress ratio A, the viscosity ratio 8, and a parameter K, which involves the influences of the phenomenological interface slip factor a or ao, the interlayer number m, and the d/Ro ratio. It was also assumed in introducing this function that (1) the TLCP phase is well dispersed, fibrillated, aligned, and just forms one interlayer (2) there is no elastic effect (3) there is no phase inversion of any kind (4) A < 1.0 and (5) a steady-state capillary flow under a constant pressure or a constant wall shear stress. 

T. K. Kim and R. M. McMeeking, Power Law Creep with Interface Slip and Diffusion in a Composite Material, Mechanics of Materials, to be published. 

Fig. 16.11 Storey shear vs. interface slip in pseudo-dynamic test of specimen no. 2 (a) at the interface of the web of the 2nd storey to the beam between the 1st and 2nd stories (b) at the interface between the web and a column in the 2nd storey...

Spacone El-Tawil 2004). The behaviour of composite beams (made of two components connected through shear connectors to form an interacting unit) is significantly influenced by the type of connection between the steel beam and the concrete slab. Flexible shear connectors allow the development of partial composite action. Thus, for accurate analytical response prediction, structural models of composite structures must account for the interlayer slip between the steel and concrete components. A composite beam finite element able to capture the interface slip is therefore an essential tool for model-based response simulation of steel-concrete composite structures. 

Compared to common monolithic beams, composite beams with deformable shear connection present additional difficulties. Even in very simple structural systems (e.g., simply supported beams), complex distributions of the interface slip and force can develop. Different finite elements of composite beams with deformable shear connection have been developed and presented in the literature (Spacone El-Tawil 2004, Dall Asta 8c Zona 2004). These elements include suitable models describing section deformations in order to compute the section force resultants of steel-concrete composite members. This requires the use of realistic material constitutive models for beam steel, reinforcement steel, concrete, and shear-slip behaviour of the studs connecting the two structural components (Zona et al. 2005, 2006, Barbato et al. 2007). 

Structural plate structures stiffened by beams are widely used in buildings, bridges, ships, aircrafts and machines. However, these structures are prone to failure of the bond between the beams and the plate. It is the behavior of this bond that gives composite construction its unique peculiarities, while interface slip can cause significant... 

The influence of the interface slip to the behavior of the stiffened plate and the accuracy of the obtained results compared with those obtained from FEM solutions are verified. 

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