Rate-Dependent Plasticity Representation for Energy-Absorbing Materials
A three dimensional rate-dependent plasticity constitutive model is developed for rigid polyurethane foams. In the model, the material is decomposed into skeleton and solid matrix from...
Constitutive Modeling and Simulation of Energy Absorbing Polyurethane Foam Under Impact Loading
The compressive-stress strain response of polyurethane foam under uniaxial compressive impact loading has been studied. The development of a uniaxial constitutive model from strain rate...
Comparative Evaluation of Plasticity Theories Against Tension-Torsion Test at Finite Strain
This paper investigates and evaluates three hardening theories against a variety of nonproportional loading experiments on tubes made of annealed copper. It was concluded that the isotropic...
Size, Temperature and Rate Effects on the Fracture Toughness of Saline Ice
This paper presents the results of an extensive experimental study performed with the aim of investigating the effects of temperature, size and loading rate on the fracture toughness of...
On the Role of Dispersive Waves in Strain-Softening Media
Wave propagation in strain-softening continua is investigated numerically and analytically. It is argued that localisation which typically acts as a precursor of failure, can only be described...
A Proposed Methodology for Ranking Space Resource Utilization Processes
A recent survey paper on lunar manufacturing identified 26 initial steps previously proposed as primary routes for lunar processing. Most of these have not been studied in sufficient detail...
Remediation Site Prioritization by the Risk Ranking and Filtering Method
The risk ranking and filtering (RRF) method, developed for ranking critical components of the NASA Space Shuttle, is a possible framework for the prioritization of hazardous-waste sites...
Environmental Impacts of Agricultural Drainage
Research has shown that improved drainage increases peak runoff rates and pollutant loads compared to natural conditions. However improved drainage on agricultural lands may reduce outflow...
Case Studies of Semi-Closed Pipeline Systems for Flexible Deliveries
The semi-closed pipeline system using the best aspects of the open and the closed pipeline systems, has many applications. It is the best adapted system for use with the variable flow...
Loading of Nutrients to Groundwater From High Source Areas During the Winter Period
Nutrient loading to surface, subsurface and groundwater in agricultural areas is the focus of control programs throughout the United States. In certain cases, high source areas can be...
The Effect of Loading Rate on the Bending Strength of Alluvium Reinforced Ice
Traditional building materials are often less than ideal for construction in remote Arctic locations. Their mechanical properties may be degraded in extreme cold, and costs associated...
On the Constitutive Behavior of Single Ice Crystals Due to Dislocation Mechanisms
A three-dimensional constitutive relation is derived for single ice crystals. The formulation is developed in terms of dislocation processes on the basal, prism, and pyramidal planes....
The Ductile-Brittle Transition in Ice & Size Effect
This paper considers the ductile to brittle transition in ice under compression. Two criteria, one phenomenological and the other more physical, are presented for the transition strain...
Preliminary Results of Direct Tension Tests on First-Year Sea Ice Samples
We present the initial results of our tests to determine the tensile behavior of columnar sea ice over a range of temperatures extending from -20 to -3?C and strain rates of 10-5...
The USACRREL Underwater Frazil Ice Detector
A modified underwater frazil ice detector has been developed at USACRREL. This detector, which operates remotely, can automatically start deicing procedures and alert operators to the...
Effects of Heterogeneity on Actinide Diffusion Rates in Tuffaceous Rock
The pore structure and mineralogy of Topopah Spring Tuff are heterogeneous on scales less than one cm. This heterogeneity creates spatial variation in transport rates for aqueous actinide...
An Alternative Method to Mariotte Reservoir System for Maintaining Constant Hydraulic Pressure
Several problems with the Mariotte reservoir system were discovered when it was used to apply a constant water pressure as a boundary condition for a prolonged period. The constant-pressure...
Siting of a Reclaimed Water Reservoir
The City of Santa Rosa (City), California, retained Woodward-Clyde Consultants to identify, evaluate, screen and rank potential sites for construction of a dam and reservoir to store reclaimed...
MORE-A Multi-Objective Ranking Environment for Risk Assessment
This paper explores the development of a computerized decision support system for ranking risks due to environmental concerns. The paper begins with a brief history a comparative risk...
Unification in Estimation of Confidence Intervals
One area of future development needs in technology pertaining to surface runoff hydrology is the unification of techniques used by govermental agencies in the estimation of surface runoff...
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