Shear Deformation of High Density Aluminum Honeycombs

2003 ◽  
Author(s):  
Wei-Yang Lu ◽  
John Korellis ◽  
Terry Hinnerichs
Keyword(s):  
Shear Deformation ◽  
Shear Test ◽  
High Density ◽  
Model Parameters ◽  
Test Beam ◽  
Model Simulations ◽  
Aluminum Honeycomb ◽  
Axis Compression ◽  
Principal Directions ◽  
Flexure Test

The orthotropic crush model has commonly been used to describe the constitutive behavior of honeycomb [1]. To completely define the model parameters of a honeycomb, experimental data of axial crushes in T, L, and W principal directions as well as shear stress-strain curves in TL, TW, and LW planes are required. The axial crushes of high-density aluminum honeycombs, e.g., 38 pcf (pound per cubic foot), under various loading speeds and temperatures have been investigated and reported [2]. This paper describes experiments and model simulations of the shear deformation of the same high-density aluminum honeycomb. Results of plate shear test, beam flexure test, and off-axis compression are presented and discussed.

scholarly journals Analysis of Cooperative Perception in Ant Traffic and Its Effects on Transportation System by Using a Congestion-Free Ant-Trail Model

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2393
Author(s):  
Prafull Kasture ◽  
Hidekazu Nishimura
Keyword(s):  
Average Velocity ◽  
Transportation System ◽  
Self Organization ◽  
Model Parameters ◽  
Agent Based ◽  
Model Simulations ◽  
Mathematical Representations ◽  
Traffic Conditions ◽  
Traffic Jams ◽  
Ant Trail

We investigated agent-based model simulations that mimic an ant transportation system to analyze the cooperative perception and communication in the system. On a trail, ants use cooperative perception through chemotaxis to maintain a constant average velocity irrespective of their density, thereby avoiding traffic jams. Using model simulations and approximate mathematical representations, we analyzed various aspects of the communication system and their effects on cooperative perception in ant traffic. Based on the analysis, insights about the cooperative perception of ants which facilitate decentralized self-organization is presented. We also present values of communication-parameters in ant traffic, where the system conveys traffic conditions to individual ants, which ants use to self-organize and avoid traffic-jams. The mathematical analysis also verifies our findings and provides a better understanding of various model parameters leading to model improvements.

High-resolution pan-European multi-model simulations of hydrologic states and fluxes

2020 ◽  
Author(s):  
Bibi S Naz ◽  
Wendy Sharples ◽  
Klaus Goergen ◽  
Stefan Kollet
Keyword(s):  
Soil Moisture ◽  
High Resolution ◽  
Groundwater Flow ◽  
Hydrologic Model ◽  
Hydrological Processes ◽  
Model Parameters ◽  
Time Step ◽  
European Continent ◽  
Model Simulations ◽  
Community Land Model

<p> <span>High-resolution large-scale predictions of hydrologic states and fluxes are important for many regional-scale applications and water resource management. However, because of uncertainties related to forcing data, model structural errors arising from simplified representations of hydrological processes or uncertain model parameters, model simulations remain uncertain. To quantify this uncertainty, multi-model simulations were performed at 3km resolution over the European continent using the Community Land Model (CLM3.5) and the ParFlow hydrologic model. While Parflow uses a similar approach as CLM in simulating the snow, vegetation and land-atmosphere exchange processes, it simulates three-dimensional variably saturated groundwater flow solving Richards equation and overland flow with a two-dimensional kinematic wave approximation. </span><span>The </span><span>CLM</span><span>3.5</span><span> uses a simple groundwater model to account for groundwater recharge and discharge processes. Both models were driven with the COSMO-REA6 reanalysis dataset at 6km resolution for the time period from 2000 to 2006 at an hourly time step, and both used the same datasets for the static input variables (such as topography, vegetation and soil properties). The performance of both models was analyzed through comparisons with independent observations including satellite-derived and in-situ soil moisture, evapotranspiration, river discharge, water table depth and total water storage datasets. Overall, both models capture the interannual variability in the hydrologic states and fluxes well, however differences in performance between models showed the uncertainty associated with the representation of hydrological processes, such as groundwater flow and soil moisture and its control on latent and sensible heat fluxes at the surface.</span></p>

Étude en laboratoire de l'adhérence béton de resurfaçage - dalle de chaussée

1992 ◽  
Vol 19 (6) ◽  
pp. 1041-1048
Author(s):  
Minh-Tan Do ◽  
Gilles Chanvillard ◽  
Claude Lupien ◽  
Pierre-Claude Aïtcin
Keyword(s):  
Key Words ◽  
Elastic Foundation ◽  
Laboratory Study ◽  
Shear Test ◽  
Bonding Agent ◽  
Bonding Agents ◽  
Test Setup ◽  
Slab Temperature ◽  
Flexure Test ◽  
Slant Shear

This paper presents a laboratory study on the bonding of a concrete overlay to an old slab. The main variables of the study were the bonding agents and the initial slab temperature when the overlay was placed. A flexure test setup, based on the theory of beams of elastic foundation, was developed. The results obtained were compared with those of the slant–shear test. Key words: bonding agent, debonding, elastic foundation, interface, beam.

A Critical Analysis of Using Step-Strain and Extensional Rheology to Obtain the Multi-mode “Pom-Pom” Model Parameters for Branched High-Density Polyethylenes

2008 ◽  
Author(s):  
Christopher D. McGrady ◽  
Christopher W. Seay ◽  
Donald G. Baird ◽  
Dietmar Auhl ◽  
Tom C. McLeish ◽  
...  
Keyword(s):  
Critical Analysis ◽  
High Density ◽  
Model Parameters ◽  
Extensional Rheology ◽  
Multi Mode ◽  
Step Strain

Characterization of Aluminum Honeycomb Material Failure in Large Deformation Compression, Shear, and Tearing

2002 ◽  
Vol 124 (4) ◽  
pp. 412-420 ◽  
Author(s):  
Qing Zhou ◽  
Robert R. Mayer
Keyword(s):  
Large Deformation ◽  
Material Characterization ◽  
Dynamic Compression ◽  
Crash Test ◽  
Characterization Methods ◽  
Aluminum Honeycomb ◽  
Principal Directions ◽  
Honeycomb Material ◽  
Static Shear

Large deformation failures of aluminum honeycomb materials in dynamic compression, static shear and static tearing are characterized in this comprehensive experimental study. Two low density honeycomb materials that make up the Offset Deformable Barrier (ODB) used in vehicle crash test were tested. Material characterization methods, including one for studying material tearing, have been developed. The honeycomb material data under large deformation, including complete curves of compression and shear stress-strain relations in the three principal directions, are presented and analyzed. Honeycomb material tearing strength, defined as tearing force per unit tearing length, is introduced. Strain-rate dependence of honeycomb materials under dynamic loading is investigated. Local failure mechanisms of honeycombs in compression, shear, and indentation punch tests and their relations with the bulk properties of the materials are studied in detail. The results of this research may be used to improve the material fidelity of finite element simulations of the ODB.

An Experimental Study of the Evolution of Yield Loci for Anisotropic Materials Subjected to Finite Shear Deformation

1991 ◽  
Vol 113 (2) ◽  
pp. 192-198 ◽  
Author(s):  
K. Mallick ◽  
Shyam K. Samanta ◽  
A. Kumar
Keyword(s):  
Shear Deformation ◽  
Anisotropic Materials ◽  
Hydraulic Testing ◽  
Experimental Results ◽  
Grain Structure ◽  
Triaxial Loading ◽  
Finite Shear ◽  
Plane Anisotropy ◽  
Principal Directions ◽  
Yield Loci

This paper presents a set of experimental results concerning the evolution of yield loci for anisotropic materials in the course of finite shear deformation history. Thin walled tubes of SAE 1020 steel are tested under triaxial loading conditions – tension, torsion and internal pressure, at room temperature. The specimens were prepared from cold-drawn tubes which had a prominent fibrous grain structure. They showed considerable amount of in-plane anisotropy and orthotropic yield properties with respect to the longitudinal and circumferential axes. The as-received specimens were further pre-strained by imposing simple shear which causes the change in orientations of these elongated polycrystalline grains. Our previous experimental results [1] have verified that the principal directions of the total stretch of the current grain shape match with the directions of orthotropy, and in this work, the subsequent yield loci for the pre-strained material are determined with respect to the new reference frame fixed along these directions of orthotropic symmetry. By utilizing the unique triaxial loading scheme of our servo-hydraulic testing system it has been possible to create the principal directions of a biaxial state of stress in a specified direction. The changes in the size and shape of the yield loci in the stress space are critically analyzed in this paper.

Experimental Study on Static Characteristics of Sandy Pebble Soil

2011 ◽  
Vol 250-253 ◽  
pp. 95-99
Author(s):  
Bin Jia ◽  
Yong Yao ◽  
Lu Cheng ◽  
Dai Guo Chen
Keyword(s):  
Shear Test ◽  
Poisson Ratio ◽  
Strain Curve ◽  
Peak Stress ◽  
Model Parameters ◽  
Horizontal Line ◽  
Static Characteristics ◽  
Stress Strain Curve ◽  
Triaxial Shear Test ◽  
Chang Model

Through the consolidation drained triaxial shear test of sandy pebble soil, the stress-strain curve of sandy pebble soil is obtained, analysis manifest that in the shearing process, shear dilatancy deformation and shear contraction deformation of sandy pebble soil are intercoupling, making asymptote of the curve after peak stress nearly a horizontal line. Meanwhile, based on the Duncan-Chang model, elastic modulus and Poisson ratio features of sandy pebble soil are analyzed, and Duncan-Chang model parameters are obtained.

scholarly journals Validation of a New Aluminum Honeycomb Constitutive Model for Impact Analyses

2006 ◽  
Author(s):  
Terry Hinnerichs ◽  
Eric Pulling ◽  
Mike Neilsen ◽  
Wei-Yang Lu
Keyword(s):  
Constitutive Model ◽  
Test Data ◽  
Model Parameters ◽  
Finite Element Code ◽  
Rate Model ◽  
Model Predictions ◽  
Aluminum Honeycomb ◽  
Impact Simulations ◽  
Orthotropic Behavior ◽  
Validation Experiments

A new constitutive model for large deformation of aluminum honeycomb has been developed. This model has 6 yield surfaces that are coupled to account for the orthotropic behavior of the cellular honeycomb being crushed on-axis and off-axis. Model parameters have been identified to fit uniaxial and biaxial crush test data for high density (38 lb/ft3) aluminum honeycomb. The honeycomb crush model has been implemented in the transient dynamic Presto finite element code for impact simulations. Simulations of calibration and validation experiments will be shown with model predictions compared with test data. Also, the honeycomb model's predictions will be compared with the older Orthotropic Rate Model predictions.

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