Viscoelastic Responses of MDF Kerf Structures

Abstract

Medium-density fiberboard (MDF), comprised of chopped wood fibers and epoxy resin is commonly used in building construction. Given the current trend in freeform architecture, there is a need to generate complex geometric structures out of common construction materials. In this study, kerfing (relief cutting) method is used to create flexible and moldable shapes out of relatively rigid wood panels. The kerf panels can be easily formed into various complex shapes for outdoor facades and/or indoor paneling. The natural wood fibers and epoxy resin in MDF combine to produce a viscoelastic composite material that exhibits time-dependent changes in mechanical behavior, i.e., material stiffness/compliance. The work described herein comes from a study designed to develop a better understanding of the viscoelastic response of kerf unit cells and panels. Experimental creep tests were performed on dog-bone specimens under uniaxial loading conditions1in order to determine the viscoelastic response of the MDF. The experimental results were used to develop a model to be used in simulations. The simulations were carried out on a kerf unit cell, e.g., a square interlocked kerf, and kerf structures of complex geometries in order to investigate the time-dependent changes in the deformations of the kerf structures. From this study, a systematic design of kerf panels with complex shapes will be developed in order to minimize the time-dependent changes of kerf structures.