Erik G. Thompson

FEAFLO: A program for the analysis of layered wood systems☆

Abstract A finite element method for the analysis of planar layered wood systems is described. The method includes the effects of slip between layers due to fastener deformations, orthotropic material properties and gaps in layers. The method was used in developing program FEAFLO (Finite Element Analysis of FLOors). Data computed at each node include the deflection, rotations, fastener forces and for each layer the axial displacements, axial forces, moments, shears and extreme fiber stresses. The method was verified by comparing measured and predicted behavior for T-beams and wood joist floors. A listing of program FEAFLO, written in ANSI FORTRAN IV, is given. The input and output data for an example floor are also given.

Finite element models for creeping convection

Abstract Finite-element thermal-mechanical models for creeping convection are developed. Examples using both quasi-Lagrangian and Eulerian formulations are presented and compared. Steady-state and transient problems are treated with attention paid to stress free boundaries.

Inclusion of elastic strain rate in the analysis of viscoplastic flow during rolling

Abstract Elastic strain rates are accounted for in a steady state, isothermal, analysis of viscoplastic flow of metal during rolling. The inclusion of the elastic strain rates allows evaluation of the residual stresses in the product, not possible from analyses based on purely viscoplastic flows.

The compaction of aggregates of non-spherical linear viscous particles

An approximate discrete-element model is used to study the compaction of aggregates of non-spherical, linear viscous particles. The numerical model is developed in which each particle is treated individually, with the appropriate constitutive relations, kinematic conditions, contact constraints, and elimination of overlap satisfied for every particle in the aggregate. Mesh update algorithms are generated based on mixed triangular and quadrilateral element system. The algorithms are used to detect contact, generate mesh, modify concave elements and prevent locking. The method could be used in a variety of problems that can be represented using granular media, such as asphalt, polymers, aluminum, snow, food product and others. A series of numerical simulations are shown to demonstrate the efficiency and accuracy of the model.

A quasi-steady-state analysis for radial forging

Abstract A steady-state approximation for the analysis of radial forging is presented. The approximation is used with the finite element method for 3-D analysis to determine billet temperatures and deformations during forging.

Water Vapor Transport in Snow A 2-D Simulation of Temperature Gradient Metamorphism

In dry snow packs experiencing a temperature gradient, heat and mass transport is responsible for the metamorphism of ice crystals. The work presented herein investigates the influence of geometry, density, and temperature on the coupled, simultaneous heat and mass transport in idealized, two dimensional ice lattice cells. Mass transfer rates, mass flux rates, concentration and temperature distributions, and effective diffusion coefficients and thermal conductivities are presented as functions of temperature, geometry, density, and time. The results of the analysis show clearly that both the mass and heat transport are strongly dependent upon the ice lattice geometry. The effective diffusion coefficient is enhanced relative to the diffusion coefficient for water vapor in air for all of the two dimensional geometries studied. In addition, the preferential growth of branch grains has been verified using both static and dynamic, computer generated images of the ice lattice cells undergoing temperature gradient metamorphism.