Date of Award

8-2002

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

Eric Landis

Second Committee Member

William Davids

Third Committee Member

Vincent Caccese

Abstract

The difficulties of describing the material properties of wood come from its complexity, anisotropy and heterogeneity that make fracture, damage and failure hard to model. This research deals with an innovative modeling approach that is similar to one that has been used for concrete.

Instead of using classical continuum-based finite element method, which has already been used extensively in the past and has not led to conclusive results, lattice models are utilized.

The microstructure can be discretized in lattice of beam or bar elements. We choose to model wood fiber bundles as beam elements, and inter-fiber adhesion with a series of transverse and diagonal springs. Material properties (Young modulus and strength) for each of these elements are statistically assigned using a Monte-Carlo simulation.

For the simulation, we choose Displacement control. At each step of the calculation, a displacement increment is applied to the structure, and the resulting forces are calculated. As damage occurs in the material, elements are progressively removed.

The studied specimens are subjected to several load cases: tension parallel-to-grain with and without notch, tension perpendicular-to-grain, shear parallel-to-grain, bending and compression parallel-to-grain. With this method, we manage to model both load-deformation response and damage characteristics of the material.

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