Deformation modeling of polyvinylidenedifluoride (PVDF) symmetrical microfiltration hollow-fiber (HF) membrane

Abstract

a b s t r a c tThe tensile deformation behavior of polyvinylidenedifluoride (PVDF) symmetrical microfiltration hollowfiber (HF) membranes was studied. The membranes had submicron pores with a three-dimensional open-cell structure. The surface and cross section of the porous membranes were observed by FESEM (field emission scanning electron microscope) to investigate the microstructure of the cell, namely, its size and ligament geometry. During uniaxial tensile tests, the membranes underwent elastic deformation and plastic deformation. Large deformation induced pore growth along the tensile direction, resulting in an increase in water permeability. In order to establish a mechanical model for tensile deformation, the finite element method (FEM) was employed. In this model, the Kelvin polyhedron (truncated octahedron structure) was used to mimic a three-dimensional open-cell structure. A one-unit cell based on this structure was created, and a periodical boundary condition was employed for the FEM computation. The FEM model could reproduce the overall elastoplastic deformation behavior of the porous membrane and provide useful insight into the fabrication of porous membranes and reliable operation of water purification.

Effect of Stretching Parameters on Structure and Properties of Polytetrafluoroethylene Hollow‐Fiber Membranes

“…A similar stress‐stain curve was also reported by Ardakani et al 31. It has been confirmed by a mechanical model that the tensile change is due to elastic deformation and plastic deformation during stretching 30, 32.…”

Microfiltration membrane processes: A review of research trends over the past decade

“…Hence, this shows, that this field is somewhat neglected in other membrane-based processes as well, and needs further consideration in integrating experimental and simulation data. Till date, MF modeling includes studying permeate flux behavior [63], particle deposition in the membrane [64], deformation behavior in membranes [65] and identification of optimum operating conditions for simple feed solutions such as green tea extracts [48], beer [66] and bio-ethanol [67].…”

Computational modeling of viscoplastic polymeric material response during micro-indentation tests

“…Regarding yield criterion, we have adopted von Mises criterion since it has been used in several research works for different applications in polymers [37], and specifically in IITs at micro and nanoscales [21,24,25,41]. However, further studies, which take other criterions into account, will need to be undertaken.…”

“…Concerning the description of plastic deformations, the yield function adopted here is based on the von Mises criterion as commonly used for polymers [21,37,41], viz.…”

“…Concerning constitutive behavior of the material under analyses in the present work, the poly vinylidene fluoride (PVDF), several computational/experimental studies has been conducted for different applications, for instance; considering an elastic viscoplastic phenomenological model of a tensile test [38] and cyclic tensile behavior [39], as well as accounting for a model based on the mechanics of porous media in experimental tensile tests [40], using periodic 3D open-cell structure for the modeling of porous membranes [41], and conducting nano-and micro-instrumented indentation experimental tests to evaluate the viscoelastic behavior of the PVDF [42].…”