A finite element analysis of the squeeze flow of an elasto-viscoplastic paste material

Adams, M.J.; Aydın, İsmail; Briscoe, B.J.; Sinha, Sujeet K.

doi:10.1016/s0377-0257(96)01546-7

Cited by 118 publications

(96 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Post yield, large plastic strains are present and the polymer deformation will resemble squeeze flow of viscoplastic material between two plates, 13,14 but with constraint at the edges due to the adjoining polymer beyond the squeezed zone. Clearly, as the squeezed film becomes thinner and its aspect ratio becomes greater, the indent load required to generate everywhere the shear ͑yield͒ stress for plastic flow rises rapidly.…”

mentioning

confidence: 99%

Influence of elastic strains on the mask ratio in glassy polymer nanoimprint

Cross

O’Connell

Pethica

2005

Applied Physics Letters

View full text Add to dashboard Cite

During glassy polymer nanoimprint, a supported film is extruded from protruding ͑punch͒ to recessed ͑cavity͒ regions of a patterned stamp. The completeness of this extrusion determines the mask ratio for lithographic applications. We show that, for a given punch contact size, there is a residual layer of unextruded material with a mean thickness that is independent of initial film thickness, stamping time, or applied maximum load. Depth sensing indentation enables us to monitor deformation during the imprinting as well as after, and so understand the deformation process involved. It is found that both the geometry and mean thickness of the residual layer are influenced by the overall elastic properties of the stamping system.

show abstract

mentioning

confidence: 99%

Influence of elastic strains on the mask ratio in glassy polymer nanoimprint

Cross

O’Connell

Pethica

2005

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…Minimizing the energy dissipation functional with respect to a parameter defining the horizontal boundary of the two zones, they obtained lower-bound solutions for Bingham materials. The work of Adams et al [14] provided experimental evidence that the yield surfaces predicted by the lubrication solution for viscoplastic fluids are erroneous. Besides, Meeten [15] carried out both theoretical and experimental investigations of the squeeze flow of Herschel Bulkley fluid.…”

Section: Introductionmentioning

confidence: 99%

“…Sherwood and Durban analyzed squeeze flow of a Bingham [23] and Herschel-Bulkley [24] materials under this slip wall boundary conditions by using an asymptotic expansion of the velocities in h/r, where r is a radial coordinate, and h the instantaneous distance between the plates. Adams et al [14] presented the results of squeeze-flow experiments of a HerschelBulkley material between two rigid plates, investigated both experimentally and computationally. Stick and slip boundary conditions were simulated and, in the case of the later, a Coulombic boundary condition was adopted.…”

Section: Introductionmentioning

confidence: 99%

Squeeze Flow of Viscoplastic Bingham Material

Muravleva¹

2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

View full text Add to dashboard Cite

Abstract. We consider both planar and axisymmetric squeeze flows of a viscoplastic medium. Firstly we deal with no-slip boundary conditions. The asymptotic and the numerical solutions are developed. Previous theoretical analysis of this problem, using the standard lubrication approximation, has led to conflicting results, whereby the material around the plane of symmetry must both behaves as unyielded solid and translates in the main direction with a nonuniform velocity. This variation of the velocity implies that the plug region cannot be truly unyielded. Our solutions show that this region is a pseudo-plug region in which the leading order equation predicts a plug, but really it is weakly yielded at higher order. We follow the asymptotic technique suggested earlier by Balmforth, Craster (1999) and Frigaad, Ryan (2004). The obtained analytical expressions and numerical results are in a very good agreement with the earlier works. For numerical simulations we apply Augmented Lagrangian method (ALM) that yields superior results regarding the location of the yieldsurface. Finite-difference method on staggered grids is used as a discretization technique.Secondly we consider squeeze flow of a Bingham fluid subject to wall slip. If the wall shearstress is smaller than the threshold value (the slip yield stress), the fluid adherence to the boundary is imposed and we have no-slip condition. When the wall shear stress reaches the slip yield stress, the fluid slips along the boundary. We solve numerically this problem also by ALM. The different flow regimes can be observed depending on the relative values of the yield stress and the slip yield stress. More precisely, for the case when the yield stress is smaller than the slip yield stress, there exists a particular value T crit such that when the slip yield stress is greater or equal to T crit ,the material fully sticks at the wall. When the slip yield stress is less than T crit and bigger than the yield stress, the fluid sticks in the central region of the wall and slips close to the outer edges of discsorplates. For the case when the yield stress is bigger than the slip yield stress the material slips on the whole boundary.1215

show abstract

“…In the last two decades, it has been applied in the concrete industry as an economical, efficient, and environmentally friendly manufacturing method for short-fiber-reinforced cement-based construction materials and products [Shao et al 1995;Shao and Shah 1997;Aldea et al 1998;Li and Mu 1998;Li et al 1999;2004;Peled and Shah 2003]. Compared with the traditional concrete casting method, extrusion techniques can significantly improve the mechanical properties of the final products through the high shear and high compression processing environment within an extruder [Shao et al 1995;Peled and Shah 2003].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of ram extrusion in short-fiber-reinforced fresh cementitious composites

Zhou

2010

JOMMS

View full text Add to dashboard Cite

A series of ram extrusion tests was carried out on a short-fiber-reinforced, semisolid, fresh cementitious composite. An elastoviscoplastic constitutive model is proposed for the extrudable fresh cementitious composite. It features the associative flow rule, a nonlinear strain rate-hardening law, and the von Mises yield criterion. The model is then implemented in ANSYS/LS-DYNA explicit finite element code.Various ram extrusion processes of the fresh cementitious composite were simulated. It has been found that the extrusion load versus imposed displacement predictions agree well with the experimental results. The fresh paste flow, through the die entry and the die-land, is then interpreted in light of the evolution of the deformation and distribution of state variables, mainly based on numerical results and the ram extrusion mechanism.The effects of extrusion ratio and extrusion velocity on extrusion load are also investigated, based on the mechanical properties of the fresh cementitious composite. The study indicates that the numerical procedure established, together with the constitutive model proposed, is applicable for describing ram extrusion of short-fiber-reinforced fresh cementitious composites, which might provide a numerical rheometric tool from which ram extrusion of elastoviscoplastic paste-like materials can be examined and quantified.

show abstract

A finite element analysis of the squeeze flow of an elasto-viscoplastic paste material

Cited by 118 publications

References 12 publications

Influence of elastic strains on the mask ratio in glassy polymer nanoimprint

Influence of elastic strains on the mask ratio in glassy polymer nanoimprint

Squeeze Flow of Viscoplastic Bingham Material

Numerical simulation of ram extrusion in short-fiber-reinforced fresh cementitious composites

Contact Info

Product

Resources

About